Altven: Indications, Dosage, Precautions, Adverse Effects
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Altven - Product Information

Manufacture: Pfizer Inc.
Country: Australia
Condition: Anxiety, Anxiety Disorder (Generalized Anxiety Disorder), Depression, Obsessive Compulsive Disorder, Panic Disorder, Stress (Anxiety and Stress), Social Anxiety Disorder
Class: Antidepressants, Serotonin-norepinephrine reuptake inhibitors
Form: Capsules
Suitable for: venlafaxine hydrochloride, iron oxide yellow CI 77492, iron oxide red CI 77491, cellulose-microcrystalline, ethyl cellulose, hypromellose, gelatin, talc, purified, titanium dioxide, red ink Opacode S-1-15094/ S-1-15095 (37.5 mg and 75 mg only), white ink TekPrint SB-0007P (150 mg only), iron oxide black CI 77499 (37.5 mg only).

venlafaxine (as hydrochloride)

Name of the Medicine

ALTVEN Venlafaxine (as hydrochloride) 37.5 mg, 75 mg and 150 mg modified release capsules.

ALTVEN contains the active ingredient venlafaxine (as hydrochloride).

The structural formula is shown below:
Chemical name:(R/S)-1-[(2-dimethylamino)-1-(4-methoxyphenyl)ethyl] cyclohexanol hydrochloride
Molecular formula:C17H27NO2.HCl
Molecular weight:313.87
CAS Registry Number:99300-78-4

Description

ALTVEN capsules are an extended-release formulation, which release the active constituent, venlafaxine hydrochloride, from spheroids within the capsule. Drug release is controlled by diffusion through the coating membrane on the spheroids and is not pH dependent. Three strengths of ALTVEN capsules are available containing either 37.5 mg, 75 mg or 150 mg of venlafaxine (as hydrochloride).

Venlafaxine hydrochloride is a white to off-white crystalline solid with a solubility of 572 mg/mL in water (adjusted to ionic strength of 0.2 M with sodium chloride).

Other ingredients are cellulose-microcrystalline, ethylcellulose and hypromellose. The capsule shells contain gelatin, red iron oxide CI 77491, yellow iron oxide CI 77492, titanium dioxide and talc purified. In addition to these, the 37.5 mg capsule shells also contain black iron oxide CI 77499. The 37.5 mg and 75 mg capsule shells are branded with Opacode S-1-15094/S-1-15095 red ink. The 150 mg capsule shells are branded with TekPrint SB-0007P white ink.

Pharmacology

Actions

Venlafaxine is a structurally novel antidepressant for oral administration; it is chemically unrelated to tricyclic, tetracyclic, or other available antidepressant agents.

Pharmacodynamics

The antidepressant action of venlafaxine in humans is believed to be associated with its potentiation of neurotransmitter activity in the central nervous system (CNS). Preclinical studies have shown that venlafaxine and its major metabolite, O-desmethylvenlafaxine (ODV), are potent inhibitors of serotonin and noradrenaline reuptake, and also weakly inhibit dopamine reuptake. Venlafaxine is a racemate. The R-enantiomer is relatively more potent than the S-enantiomer with regard to inhibition of noradrenaline reuptake; the S-enantiomer is more potent regarding inhibition of serotonin reuptake. Both enantiomers are more potent on serotonin compared to noradrenaline reuptake. The enantiomers of ODV also inhibit both noradrenaline and serotonin reuptake, with the R-enantiomer being more potent. Venlafaxine and its major metabolite appear to be equipotent with respect to their overall action on neurotransmitter re-uptake and receptor binding. Studies in animals show that tricyclic antidepressants may reduce β-adrenergic receptor responsiveness following chronic administration. In contrast, venlafaxine and ODV reduce β-adrenergic responsiveness after both acute (single dose) and chronic administration.

Venlafaxine has no significant affinity for rat brain muscarinic, H1-histaminergic or α1-adrenergic receptors in vitro. Pharmacological activity at these receptors is potentially associated with various sedative, cardiovascular, and anticholinergic effects seen with other psychotropic drugs. Venlafaxine does not possess monoamine oxidase (MAO) inhibitory activity.

In vitro studies revealed that venlafaxine has virtually no affinity for opiate, benzodiazepine, phencyclidine (PCP), or N-methyl-D-aspartic acid (NMDA) receptors. Venlafaxine also does not produce noradrenaline release from brain slices. It has no significant CNS stimulant activity in rodents. In primate drug discrimination studies, venlafaxine showed no significant stimulant or depressant abuse liability.

Pharmacokinetics

Steady-state concentrations of venlafaxine and ODV are attained within 3 days of oral multiple-dose therapy. Venlafaxine and ODV exhibited linear kinetics over the dose range of 75 to 450 mg / day. Mean ± SD steady-state plasma clearance of venlafaxine and ODV is 1.3±0.6 and 0.4±0.2 L/h/kg, respectively; apparent elimination half-life is 5±2 and 11±2 hours, respectively; and apparent (steady-state) volume of distribution is 7.5±3.7 and 5.7±1.8 L/kg, respectively.

Absorption

On the basis of mass balance studies, at least 92% of a single oral dose of venlafaxine is absorbed, indicating that absorption of venlafaxine is nearly complete. However, the presystemic metabolism of venlafaxine (which primarily forms the active metabolite, ODV) reduces the absolute bioavailability of venlafaxine to 42%±15%.

After administration of venlafaxine modified-release capsule (150 mg q24 hours), the peak plasma concentrations (Cmax) of venlafaxine (150 ng/mL) and ODV (260 ng/mL) were attained within 6.0±1.5 and 8.8±2.2 hours, respectively. The rate of absorption of venlafaxine from the capsule is slower than its rate of elimination. Therefore, the apparent elimination half-life of venlafaxine following administration of venlafaxine modified-release capsule (15±6 hours) is actually the absorption half-life instead of the true disposition half-life (5±2 hours) observed following administration of an immediate-release tablet.

When equal doses of venlafaxine, administered either as an immediate-release tablet taken in divided doses or as a modified-release capsule, were taken once a day, the exposure (AUC, area under the concentration curve) to both venlafaxine and ODV was similar for the two treatments, and the fluctuation in plasma concentrations was slightly lower following treatment with the venlafaxine modified-release capsule. Therefore, the venlafaxine modified-release capsule provides a slower rate of absorption, but the same extent of absorption (i.e., AUC), as the venlafaxine immediate-release tablet.

No accumulation of venlafaxine or ODV has been observed during chronic administration in healthy subjects.

Distribution

The degree of binding of venlafaxine to human plasma proteins is 27%±2% at concentrations ranging from 2.5 to 2215 ng/mL, and the degree of ODV binding to human plasma proteins is 30%±12% at concentrations ranging from 100 to 500 ng/mL. Protein-binding-induced drug interactions with concomitantly administered venlafaxine are not expected. Following intravenous administration, the steady-state volume of distribution of venlafaxine is 4.4±1.9 L/kg, indicating that venlafaxine distributes well beyond the total body water.

Metabolism

Following absorption, venlafaxine undergoes extensive presystemic metabolism in the liver. The primary metabolite of venlafaxine is ODV, but venlafaxine is also metabolised to N-desmethylvenlafaxine, N,O-didesmethylvenlafaxine, and other minor metabolites. In vitro studies indicate that the formation of ODV is catalysed by CYP2D6 and that the formation of N-desmethylvenlafaxine is catalysed by CYP3A3/4. The results of the in vitro studies have been confirmed in a clinical study with subjects who are CYP2D6-poor and -extensive metabolisers. However, despite the metabolic differences between the CYP2D6-poor and - extensive metabolisers the total exposure to the sum of the two active species (venlafaxine and ODV) was similar in the two metaboliser groups. Therefore, CYP2D6-poor and - extensive metabolisers can be treated with the same regimen of ALTVEN (see Interactions With Other Medicines -CYP2D6 Inhibitors).

Excretion

Approximately 87% of a venlafaxine dose is recovered in the urine within 48 hours after a single radio-labelled dose as either unchanged venlafaxine (5%), unconjugated ODV (29%), conjugated ODV (26%), or other minor inactive metabolites (27%), and 92% of the radioactive dose is recovered within 72 hours. Therefore, renal elimination of venlafaxine and its metabolites is the primary route of excretion.

The ALTVEN formulation of venlafaxine contains spheroids, which release the drug slowly into the digestive tract. The insoluble portion of these spheroids is eliminated and may be seen in stools.

Food-Drug Interactions

Administration of ALTVEN with food has no effect on the absorption of venlafaxine or on the subsequent formation of ODV.

Special Populations

Age and Gender

Subject age and sex do not significantly affect the pharmacokinetics of venlafaxine. A 20% reduction in clearance was noted for ODV in subjects over 60 years old; this was probably caused by the decrease in renal function that typically occurs with aging.

Renal Impairment

In patients with moderate to severe impairment of renal function, the total clearance of both venlafaxine and ODV was reduced, and t½ was prolonged. The reduction in total clearance was most pronounced in subjects with creatinine clearance less than 30 mL/min.

Hepatic Impairment

In some patients with compensated hepatic cirrhosis, the pharmacokinetic disposition of both venlafaxine and ODV was significantly altered. The reduction in both the metabolism of venlafaxine and elimination of ODV resulted in higher plasma concentrations of both venlafaxine and ODV.

Clinical Trials

Major Depression

Three double blind, placebo controlled trials, of up to 12 weeks duration, have examined the clinical efficacy of venlafaxine modified-release capsule in the treatment of major depression. One of these studies also incorporated an active comparator, paroxetine. These studies showed venlafaxine modified-release capsule to have greater efficacy than both placebo and paroxetine in reducing depression.

Generalised Anxiety Disorder

Five placebo-controlled trials were conducted to evaluate the efficacy of venlafaxine modified-release capsule in the treatment of anxiety. Two trials were eight-week studies, utilising venlafaxine modified-release capsule doses of 75 mg, 150 mg and 225 mg/day and of 75 mg and 150 mg/day. In one of these, buspirone was found not to be significantly different to placebo or to venlafaxine modified-release capsule. However, venlafaxine modified-release capsule was found to be superior to placebo. Two other trials were the first eight-weeks of two long term studies, utilising venlafaxine modified-release capsule doses of 75 mg-225 mg/day and of 37.5 mg, 75 mg and 150 mg/day.

Four studies demonstrated superiority of venlafaxine modified-release capsule over placebo on at least five of the following efficacy scales: HAM-A total score, the HAM-A psychic anxiety factor, the Hospital Anxiety and Depression (HAD) anxiety subscale, and the CGI severity of illness scale, as well as the HAM-A anxious mood and tension item. Two of these four studies continued for up to six months. These two studies, which utilised venlafaxine modified-release capsule doses of 75 mg – 225 mg/day and 37.5 mg, 75 mg and 150 mg/day demonstrated superiority of venlafaxine modified-release capsule over placebo on the HAM-A total score, HAM-A psychic anxiety factor, the HAD anxiety factor, and the CGI severity of illness scale, as well as the HAM-A anxious mood item.

The fifth trial was a short-term (8-week) comparison of the efficacy of 2 fixed doses of venlafaxine modified-release capsule (75 mg and 150 mg) with placebo and diazepam followed by a comparison of the long-term (6-month) efficacy of venlafaxine modified-release capsule and placebo in the prevention of relapse. The most important results were the primary efficacy variables at week 8 using an LOCF analysis. These demonstrated no significant differences between either venlafaxine and placebo, or diazepam and placebo for any of the primary efficacy variables. In view of this failure to demonstrate any effectiveness of either venlafaxine or diazepam over placebo, the long-term outcomes of this study are not of clinical or theoretical value. In conclusion, this study showed no anxiolytic effect of either diazepam or placebo in the short-term (8 week phase).

Baseline and Final Mean HAM-A Total and CGI Severity Scores for Placebo-Controlled GAD Studies
Study NumberHAM-A TotalCGI Severity
TreatmentnBaselineFinalnBaselineFinal
210 (8-week study)
Placebo9624.114.7964.43.2
Venlafaxine XR (mg)
758624.713.5864.53
1508124.512.3814.52.9
2258623.611.9864.42.8
214 (8-week study)
Placebo9823.715.4984.33.3
Venlafaxine XR (mg)
758723.713874.23.3
150872313.6874.23
Buspirone9323.814.3934.23.2
218 (6-month study)
Placebo12324.916.21234.43.5
Venlafaxine XR (mg)
75-2251152511.61154.42.7
377 (8-week period)
Placebo9627.715.1894.83.2
Venlafaxine XR (mg)
751812812.81604.92.9
1501692814.21464.93.1
Diazepam8928.413.5794.82.9
378 (6-month study)
Placebo12926.715.61294.63.2
Venlafaxine XR (mg)
37.513826.612.61384.42.6
7513026.310.41294.42.4
15013126.39.51314.62.2

Depression Relapse/Recurrence

A long-term study of depressed outpatients who had responded to venlafaxine modified-release capsule during an initial 8-week open-label treatment phase and were randomly assigned to continuation on venlafaxine modified-release capsule or placebo for 6 months demonstrated a significantly lower relapse rate for patients taking venlafaxine modified-release capsule compared with those on placebo.

In a second long-term study, outpatients with a history of recurrent depression who had responded to venlafaxine immediate-release formulation by 8 weeks and maintained improvement during an initial 6-month open-label treatment phase were randomly assigned to maintenance therapy on venlafaxine immediate-release formulation or placebo for 12 months. Significantly fewer patients taking venlafaxine immediate-release formulation compared with those on placebo had a reappearance of depression.

Social Anxiety Disorder

The efficacy of venlafaxine modified-release capsule as a treatment for social anxiety disorder (also known as social phobia) was established in four double-blind, parallel-group, 12-week, multi-centre, placebo-controlled, flexible-dose studies and one double-blind, parallel-group, 6-month, fixed/flexible-dose study in adult outpatients meeting the Diagnostic and Statistical Manual (DSM)-IV criteria for Social Anxiety Disorder. Patients received doses in a range of 75-225 mg/day. Efficacy was assessed with the Liebowitz Social Anxiety Scale (LSAS). The LSAS measures the relationship of impairment because of social anxiety disorder symptoms by evaluating a patient's fear and avoidance in a broad range of situations (i.e., 13 performance and 11 social interaction situations). Psychometric studies have shown the LSAS to be a valid and reliable measure of social anxiety.1 The LSAS scale has also been shown to be sensitive to differences between active and placebo treatments.2

1 Clark DB, et al. Systematic assessment of social phobia in clinical practice. Depress and Anxiety 1997;6:47-61.
2 Davidson JRT, et al. Treatment of social phobia with clonazepam and placebo. J Clin Psychopharmacol. 1993;13:423-428

The results of these trials are presented in the table below. In these five trials, venlafaxine modified-release capsule was significantly more effective than placebo on change from baseline to endpoint on the LSAS total score.

Summary of Results for Primary Efficacy Variable in ITT Patients at Final On-Therapy Visit: 12 week and 6 month
Variable
Study Number
Treatment Group
No. of PatientsRaw baseline
Score
Adjusted Final
On-therapy
Score
Adjusted Mean
Change from Baseline
p-value vs.
Placebo
Short-term (12 week) Studies
LSAS
Study 1
Placebo13886.769-19.9
Venlafaxine XRa13391.157.8-31<0.001
Study 2b
Placebo13587.466.9-22.1
Venlafaxine XRa12690.856.3-32.80.003
Study 3
Placebo13283.664.5-19.1
Venlafaxine XRa12983.247.6-36<0.001
Paroxetinec12883.948.1-35.4<0.001
Study 4
Placebo14486.164.3-22.2
Venlafaxine XR13386.251.5-35<0.001
Paroxetine13687.247.3-39.2<0.001
Long-term (6 month) Study
LSAS
Study 5
Placebo12689.365.6-23.5
Venlafaxine XR (total)d2388951.2-37.8<0.001
Venlafaxine XR 75mg11991.851-38.1<0.001
Venlafaxine 150-225mg11986.251.5-37.6<0.001

a: Flexible dose range for venlafaxine XR was 75-225mg/day; b: Data shown are for ITT population; c: Flexible dose range for paroxetine was 20-50mg/day; d: Primary treatment group. Abbreviations: ITT = intent to treat; LSAS = Liebowitz Social Anxiety Scale.

Panic Disorder

The efficacy of venlafaxine modified-release capsules as a treatment for panic disorder was established in two double-blind, 12-week, multicentre, placebo-controlled studies in adult outpatients meeting DSM-IV criteria for panic disorder, with or without agoraphobia. Patients received fixed doses of 75 or 150 mg/day in one study (Study 1) and 75 or 225 mg/day in the other study (Study 2).

In one flexible-dose study (Study 3) (75 mg to 225 mg daily doses), the primary outcome, the percentage of patients free of full-symptom panic attacks, approached significance (p=0.056). In this study, venlafaxine modified-release capsule was significantly more effective than placebo for the two key secondary outcomes, (1) mean change from baseline to endpoint on the Panic Disorder Severity Scale (PDSS) total score, and (2) percentage of patients rated as responders (much improved or very much improved) in the Clinical Global Impressions (CGI) Improvement scale.

In another flexible-dose study (Study 4) (dose range 75 mg to 225 mg per day), venlafaxine modified-release capsule was not significantly more effective than placebo for the primary outcome, the percentage of patients free of full-symptom panic attacks, but it was significantly more effective than placebo for the secondary outcome, percentage of patients rated as responders (much improved or very much improved) in the Clinical Impressions (CGI) Improvement scale.

Efficacy was assessed on the basis of outcomes in three variables: (1) percentage of patients free of full-symptom panic attacks on the Panic and Anticipatory Anxiety Scale (PAAS), (2) mean change from baseline to endpoint on the Panic Disorder Severity Scale (PDSS) total score, and (3) percentage of patients rated as responders (much improved or very much improved) in the Clinical Global Impressions (CGI) Improvement scale. In Studies 1 and 2, venlafaxine modified-release capsule was significantly more effective than placebo in all three variables.

Primary Efficacy Variable PAAS: Percent of Patients Free of Full-Symptom Panic Attacks, Final On-Therapy (12 weeks in Studies 1 and 2, 10 weeks in Studies 3 and 4), ITT Population.
StudyTreatmentnNumber (%) Panic
Free
p-value vs. Placeboa
1Placebo15453 (34.4)
Venlafaxine XR 75 mg15785 (54.1)<0.001
Venlafaxine XR 150 mg15897 (61.4)<0.001
Paroxetine16096 (60.0)<0.001
2Placebo15773 (46.5)
Venlafaxine XR 75 mg156100 (64.1)<0.001
Venlafaxine XR 225 mg160112 (70.0)<0.001
Paroxetine15189 (58.9)0.008
3Placebo15563 (40.6)
Venlafaxine XR 75-225 mg15579 (51.0)0.056
4bPlacebo16888 (52.4)
Venlafaxine XR 75-225 mg16088 (55.0)0.622

Abbreviations: PAAS = Panic and Anticipatory Anxiety Scale; ITT= Intent to treat,
a: Chi-square p-values obtained from logistic regression model logit (response) = Treatment + center in studies 1, 3 and 4 and logistic regression model logit (response) = baseline + treatment + center in study 2.
b: excluding site 39127.

Examination of subsets of the population studied did not reveal any differential responsiveness on the basis of gender. There was insufficient information to determine the effect of age or race on outcome in these studies.

In a longer-term study (Study 5), adult outpatients meeting DSM-IV criteria for panic disorder who had responded during a 12-week open phase with venlafaxine modified-release capsule (75 to 225 mg/day) were randomly assigned to continue the same venlafaxine modified-release capsule dose (75, 150, or 225 mg) or switch to placebo for observation for relapse during a 6-month double-blind phase. Response during the open phase was defined as >1 full-symptom panic attack per week during the last 2 weeks of the open phase and a CGI Improvement score of 1 (very much improved) or 2 (much improved). Relapse during the double-blind phase was defined as having 2 or more full-symptom panic attacks per week for 2 consecutive weeks or having discontinued due to loss of effectiveness. Patients receiving continued venlafaxine modified-release capsule treatment experienced significantly lower relapse rates over the subsequent 6 months compared with those receiving placebo.

Survival Analysis for Relapse of Panic Disorder, ITT Patients, Double-Blind Period
Therapy GroupNo. of
Patients
Number of Relapse
(%)
Cumulative Probability of
Relapse
p-valuesa
Placebo8040(50,0)0.523
Venlafaxine8920(22,5)0.239<0.001

a: p-values obtained from log-ranked statistics of Kaplan-Meier survival model.

Indications

ALTVEN is indicated for the treatment of:

  • Major Depression, including prevention of relapse and recurrence where appropriate
  • Generalised Anxiety Disorder
  • Social Anxiety Disorder
  • Panic Disorder, including prevention of relapse.

Contraindications

Hypersensitivity to venlafaxine or any excipients in the formulation.

Monoamine Oxidase Inhibitors (MAOIs)

ALTVEN should not be used in combination with monoamine oxidase inhibitors (MAOIs) or reversible MAOIs (RIMA) (e.g. moclobemide, linezolid and intravenous methylene blue), or within 14 days of discontinuing treatment with a MAOI. Similarly, at least 7 days should be allowed after stopping ALTVEN before starting a MAOI. Cases of serious reactions, such as potentially life-threatening serotonin syndrome (characterised by neuromuscular excitation, altered mental status and autonomic dysfunction) have been reported in patients receiving an SNRI in combination with MAOIs and RIMA, and in patients who have recently discontinued an SNRI and have been started on a MAOI (see also Precautions and Interactions With Other Medicines).

Precautions

Clinical Worsening and Suicide Risk

Patients with major depression, both adult and paediatric, may experience worsening of their depression and/or the emergence of suicidal ideation and behaviour (suicidality) or unusual changes in behaviour, whether or not they are taking antidepressant medications, and this risk may persist until significant remission occurs. Suicide is a known risk of depression and certain other psychiatric disorders, and these disorders themselves are the strongest predictors of suicide. Antidepressants may have a role in inducing worsening of depression and the emergence of suicidality in certain patients during the early phases of treatment. As improvement may not occur during the first few weeks or more of treatment, patients should be monitored appropriately and observed closely for clinical worsening and suicidality, especially at the beginning of a course of treatment or at the time of dose changes, either increases or decreases.

Pooled analyses of short-term placebo-controlled trials of antidepressant medicines (Selective Serotonin Reuptake Inhibitor [SSRIs] and others) showed that these medicines increase the risk of suicidality in children, adolescents, and young adults (ages 18-24 years) with major depression and other psychiatric disorders. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults older than 24 years of age; there was a reduction in the risk of suicidality with antidepressants compared to placebo in adults aged 65 years and older.

The pooled analysis of placebo-controlled trials in children and adolescents with major depression, obsessive compulsive disorder, or other psychiatric disorders included a total of 24 short-term trials of nine antidepressant medicines in over 4400 patients. The pooled analyses of placebo-controlled trials in adults with major depression or other psychiatric disorders included a total of 295 short-term trials (median duration 2 months) of 11 antidepressant medicines in over 77,000 patients. There was considerable variation in risk of suicidality among medicines, but a tendency toward an increase in the younger patients for almost all medicines studied. There were differences in absolute risk of suicidality across the different indications, with the highest incidence with major depression.

No suicides occurred in any of the paediatric trials. There were suicides in the adult trials, but the number was not sufficient to reach any conclusion about the medicine effect on suicide.

It is unknown whether the suicidality risk extends to longer-term use, i.e. beyond several months. However, there is substantial evidence from placebo-controlled maintenance trials in adults with depression that the use of antidepressants can delay the recurrence of depression.

Consideration should be given to changing the therapeutic regimen, including possibly discontinuing the medication, in patients whose depression is persistently worse or whose emergent suicidality is severe, abrupt in onset, or was not part of the patient’s presenting symptoms (see Discontinuation Effects below).

It is particularly important that appropriate monitoring be undertaken during the initial course of antidepressant treatment or at times of dose increase or decrease.

Patients with co-morbid depression associated with other psychiatric or non-psychiatric disorders being treated with antidepressants should be similarly observed for clinical worsening and suicidality.

Symptoms of anxiety, agitation, panic attacks, insomnia, irritability, hostility (aggressiveness), impulsivity, akathisia (psychomotor restlessness), hypomania and mania, have been reported in adults, adolescents and children being treated with antidepressants for major depression as well as for other indications, both psychiatric and non-psychiatric. Although a causal link between the emergence of such symptoms and either worsening of depression and /or emergence of suicidal impulses has not been established, there is concern that such symptoms may be precursors of emerging suicidality.

Prescriptions for ALTVEN should be written for the smallest quantity of capsules consistent with good patient management in order to reduce the possibility of overdosage. This is particularly so at the times of treatment initiation or dosage change. Events reported in overdose include electrocardiogram changes (QRS prolongation, QT prolongation), cardiac arrhythmias (ventricular fibrillation; ventricular tachycardia, including torsade de pointes), convulsions, and death (see Overdosage).

Information for Patients and Caregivers

Patients, their families and their caregivers should be alerted about the need to monitor for the emergence of anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia (psychomotor restlessness), hypomania, mania, other unusual changes in behaviour, worsening of depression, and suicidal ideation, especially when initiating therapy or during any change in dose. Such symptoms should be reported to the patient’s doctor, especially if they are severe, abrupt in onset, or were not part of the patient’s presenting symptoms (see also Precautions - Paediatric Use).

Akathisia/Psychomotor Restlessness

The use of venlafaxine has been associated with the development of akathisia, characterised by a subjectively unpleasant or distressing restlessness and need to move, often accompanied by an inability to sit or stand still. This is most likely to occur within the first few weeks of treatment. In patients who develop these symptoms, increasing the dose may be detrimental.

Serotonin Syndrome or Neuroleptic Malignant Syndrome (NMS)-Like Reactions

As with other serotonergic agents, serotonin syndrome, a potentially life-threatening condition, or NMS-like reactions may occur with venlafaxine treatment, particularly with concomitant use of other serotonergic drugs (including SSRIs, SNRIs, triptans, fentanyl, dextromethorphan, tramadol, tapentadol, pethidine and methadone), and with drugs that impair metabolism of serotonin (e.g. MAOIs, including reversible MAOIs such as moclobemide, linezolid and intravenous methylene blue), or with antipsychotics or other dopamine antagonists (see Contraindications).

Symptoms of serotonin syndrome may include mental status changes (e.g., agitation, confusion, hallucinations, and coma), autonomic instability (e.g., diaphoresis, tachycardia, labile blood pressure, and hyperthermia), neuromuscular aberrations (e.g., hyperreflexia, incoordination, myoclonus, tremor) and/or gastrointestinal symptoms (e.g., nausea, vomiting, and diarrhoea). Serotonin syndrome, in its most severe form, can resemble NMS, which includes hyperthermia, muscle rigidity, autonomic instability with possible rapid fluctuation of vital signs and mental status changes (see Interactions With Other Medicines).

If concomitant treatment with venlafaxine and other agents that may affect the serotonergic and/or dopaminergic neurotransmitter systems is clinically warranted, careful observation of the patient is advised, particularly during treatment initiation and dose increases.

The concomitant use of venlafaxine with serotonin precursors (such as tryptophan supplements) is not recommended.

Treatment with ALTVEN should be discontinued if serotonin syndrome or NMS-Like reactions occur and supportive symptomatic treatment initiated.

Bone Fractures

Epidemiological studies show an increased risk of bone fractures in patients receiving serotonin reuptake inhibitors (SRIs) including venlafaxine. The mechanism leading to this risk is not fully understood.

Diabetes

In patients with diabetes treatment with an SSRI may alter glycaemic control. Insulin and/or hypoglycaemic dosage may need to be adjusted.

Angle Closure Glaucoma

Mydriasis may occur in association with venlafaxine. It is recommended that patients with raised intra-ocular pressure or patients at risk for acute narrow-angle glaucoma (angle closure glaucoma) should be closely monitored.

Sustained Hypertension

Dose-related increases in blood pressure have been reported in some patients treated with venlafaxine.

Among patients treated with 75 to 375 mg per day of venlafaxine modified-release capsule in pre-marketing depression studies, 3% (19/705) experienced sustained hypertension [defined as treatment-emergent supine diastolic blood pressure (SDBP) ≥90 mm Hg and ≥10 mm Hg above baseline for 3 consecutive on-therapy visits]. Among patients treated with 37.5 to 225 mg per day of venlafaxine modified-release capsule in pre-marketing GAD studies, 0.5% (5/1011) experienced sustained hypertension. Experience with the immediate-release venlafaxine showed that sustained hypertension was dose-related, increasing from 3 to 7% at 100 to 300 mg per day to 13% at doses above 300 mg per day. An insufficient number of patients received mean doses of venlafaxine modified-release capsule over 300 mg per day to fully evaluate the incidence of sustained increases in blood pressure at these higher doses.

In placebo-controlled pre-marketing depression studies with venlafaxine modified-release capsule 75 to 225 mg per day, a final on-drug mean increase in supine diastolic blood pressure (SDBP) of 1.2 mm Hg was observed for venlafaxine modified-release capsule treated patients compared with a mean decrease of 0.2 mm Hg for placebo-treated patients. In placebo-controlled pre-marketing GAD studies with venlafaxine modified-release capsule 37.5 to 225 mg per day up to 8 weeks or up to 6 months, a final on-drug mean increase in SDBP of 0.3 mm Hg was observed for venlafaxine modified-release capsule treated patients compared with a mean decrease of 0.9 and 0.8 mm Hg, respectively, for placebo-treated patients. In pre-marketing Social Anxiety Disorder studies up to 12 weeks, the final on-therapy mean change from baseline in SDBP was small - an increase of 0.78 mm Hg, compared to a decrease of 1.41 mm Hg in placebo-treated patients. In a 6-month study, the final on-therapy mean increase from baseline in SDBP with venlafaxine modified-release capsule 150 to 225 mg was 1.49 mm Hg. The increase was significantly different from the 0.6 mm Hg decrease with placebo and the 0.2 mm Hg decrease with venlafaxine modified-release capsule 75 mg.

In pre-marketing depression studies, 0.7% (5/705) of the venlafaxine modified-release capsule treated patients discontinued treatment because of elevated blood pressure. Among these patients, most of the blood pressure increases were in a modest range (12 to 16 mm Hg, SDBP). In pre-marketing GAD studies up to 8 weeks and up to 6 months, 0.7% (10/1381) and 1.3% (7/535) of the venlafaxine modified-release capsule treated patients, respectively, discontinued treatment because of elevated blood pressure. Among these patients, most of the blood pressure increases were in a modest range (12 to 25 mm Hg, SDBP up to 8 weeks; 8 to 28 mm Hg up to 6 months).

Cases of elevated blood pressure requiring immediate treatment have been reported in post-marketing experience.

Sustained increases of SDBP could have adverse consequences. Therefore it is recommended that patients receiving ALTVEN have regular monitoring of blood pressure. For patients who experience a sustained increase in blood pressure while receiving venlafaxine, either dose reduction or discontinuation should be considered. Pre-existing hypertension should be controlled before treatment with venlafaxine. Caution should be exercised in patients whose underlying conditions might be compromised by increases in blood pressure.

Increase in Serum Cholesterol

Clinically relevant increases in serum cholesterol were recorded in 5.3% of venlafaxine immediate release tablet-treated patients and 0.0% of placebo-treated patients for at least 3 months in placebo-controlled clinical trials.

Treatment with venlafaxine modified-release capsule for up to 12 weeks in pre-marketing placebo-controlled depression trials was associated with a mean final on-therapy increase in serum cholesterol concentration of approximately 0.039 mmol/L (1.5 mg/dL). Venlafaxine modified-release capsule treatment for up to 8 weeks and up to 6 months in pre-marketing placebo-controlled GAD trials was associated with mean final on-therapy increases in serum cholesterol concentration of approximately 0.026 mmol/L (1.0 mg/dL) and 0.059 mmol/L (2.3 mg/dL), respectively.

In the 12 week Social Anxiety Disorder studies, small mean increases in fasting levels of total cholesterol (0.20 mmol/L, 4%) were seen in the venlafaxine modified-release capsule-treated group at the final on-therapy evaluation; the increases were significantly different from the changes in the placebo group. In a 6-month study, the final on-therapy mean increase in total cholesterol was higher (0.32 mmol/L, 7%) in the venlafaxine modified-release capsule 150 to 225 mg group; however the total cholesterol value was only slightly increased (0.01mmol/L) for the venlafaxine modified-release capsule 75 mg group.

There were also significant mean increases from baseline in LDL, but not HDL for the venlafaxine modified-release capsule 150 to 225 mg group. The final on-therapy increase of 0.213 mmol/L from baseline in LDL with venlafaxine modified-release capsule 150 to 225 mg was significantly different from the small decrease with placebo (0.079 mmol/L) and the negligible increase with venlafaxine modified-release capsule 75mg (0.006 mmol/L).

Measurement of serum cholesterol levels should be considered during long-term treatment.

Hyponatraemia

Cases of hyponatraemia, and/or the Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH) may occur with venlafaxine, usually in volume-depleted or dehydrated patients. Elderly patients, patients taking diuretics, and patients who are otherwise volume depleted, may be at greater risk for this event.

Caution is advised in administering ALTVEN to patients with diseases or conditions that could affect haemodynamic responses or metabolism.

Use in Patients with Pre-Existing Heart Disease

Patients with a recent history of myocardial infarction or unstable heart disease were excluded from all venlafaxine clinical trials. However, patients with other pre-existing heart disease were not excluded, although they were neither separately analysed nor systematically studied.

Venlafaxine should be used with caution in patients with unstable heart disease (e.g. myocardial infarction; significant left ventricular dysfunction, ventricular arrhythmia). In these patients, assessment of the cardiovascular system (e.g. ECG; serum electrolytes during diuretic treatment) should be considered during treatment with venlafaxine, particularly when the dose is increased beyond 150-200 mg daily.

Evaluation of the electrocardiograms for 769 patients who received immediate release venlafaxine in 4 to 6-week double blind, placebo-controlled trials showed that the incidence of trial-emergent conduction abnormalities did not differ from that with placebo.

The electrocardiograms for patients who received venlafaxine modified-release capsule or placebo in the depression GAD and Social Anxiety Disorder trials were analysed. The mean change from baseline in corrected QT interval (QTc) for venlafaxine modified-release capsule treated patients in depression studies was increased relative to that for placebo-treated patients (increase of 4.7 msec for venlafaxine modified-release capsule and decrease of 1.9 msec for placebo). The mean change from baseline QTc for venlafaxine modified-release capsule treated patients in the GAD studies did not differ significantly from placebo. The final on-therapy mean increase from baseline in QTc (3 msec) was significant for venlafaxine modified-release capsule treated patients in the Social Anxiety Disorder short-term studies. In the 6 month study, the final on-therapy mean increase from baseline in QTc with venlafaxine modified-release capsule 150 to 225 mg (3 msec) was significant, but the increase was not significantly different from the small mean increase (0.5 msec) with placebo. The value for venlafaxine modified-release capsule 75 mg was a 0.05 msec decrease.

Increases in heart rate may occur, particularly with higher doses. Therefore caution is advised in patients whose underlying conditions may be compromised by increases in heart rate.

The mean change from baseline in heart rate for venlafaxine modified-release capsule treated patients in both the GAD and depression studies was significantly higher than for placebo (a mean increase of 3-4 beats per minute for venlafaxine modified-release capsule and 0-1 beat per minute for placebo in the GAD and depression studies respectively). In the pooled short-term Social Anxiety Disorder studies, the final on-therapy mean increase from baseline in heart rate with venlafaxine modified-release capsule was 5 beats per minute. In the 6 month study, the final on-therapy mean increases from baseline in heart rate were significant with venlafaxine modified-release capsule 75 (2 beats per minute) and venlafaxine modified-release capsule 150 to 225 mg (6 beats per minute); however only the increase with the higher dose was significantly different from the small increase with placebo (0.4 beats per minute). The clinical significance of these changes is unknown.

QTc Prolongation/Torsade de Pointes (TdP)

Cases of QTc prolongation, torsade de pointes (TdP), ventricular tachycardia and sudden death have been reported during the post-marketing use of venlafaxine. The majority of reports occurred in association with overdose or in patients with other risk factors for QTc prolongation/TdP. Therefore venlafaxine should be used with caution in patients with risk factors for QTc prolongation.

Discontinuation Effects

Discontinuation effects are well known to occur with antidepressants. Discontinuation symptoms have been assessed both in patients with depression and in those with anxiety. Abrupt discontinuation, dose reduction, or tapering of venlafaxine at various doses has been found to be associated with the appearance of new symptoms, the frequency of which increased with increased dose level and with longer duration of treatment.

Symptoms reported included agitation, anorexia, anxiety, confusion, dry mouth, fatigue, paraesthesias, vertigo, hypomania, nausea, vomiting, dizziness, convulsion, headache, diarrhoea, sleep disturbance, insomnia, somnolence, sweating and nervousness. Where such symptoms occurred, they were usually self-limiting, but in a few patients lasted for several weeks.

Discontinuation effects were systematically studied in a long-term fixed-dose trial for generalised anxiety disorder; 24% and 11% of patients recorded the appearance of at least three withdrawal symptoms on abrupt discontinuation from 150 mg or 75 mg venlafaxine once daily, respectively, compared with 3% for placebo. The most commonly reported withdrawal symptoms on abrupt discontinuation were nausea, vomiting, dizziness, lightheadedness, and tinnitus from 150 mg venlafaxine once daily, and dizziness from 75 mg venlafaxine once daily.

In this study, severe withdrawal reactions were observed in 1.3% of patients discontinuing from 75 mg once daily (no patients requiring further drug treatment).

There is also a report of a withdrawal syndrome, confirmed by two challenges in a 32-year-old woman who had received venlafaxine 300 mg daily for 8 months. It is, therefore, recommended that the dosage of ALTVEN be tapered gradually and the patient monitored.

The period required for discontinuation may depend on the dose, duration of therapy and the individual patient (see Dosage and Administration and Adverse Effects).

Altered Weight

Weight changes, either losses or gains, do not appear to present a clinically important feature of venlafaxine treatment. Clinically significant weight gain or loss was seen in less than 1% of patients treated with venlafaxine during clinical trials. A dose-dependent weight loss (mean loss <1 kg) was noted in some patients treated with venlafaxine during the first few months of venlafaxine treatment. After month 9, the mean weight began to increase slightly but significantly, an effect often seen with tricyclic antidepressant therapy. Significant weight loss (> 7 kg) was seen in 6 (0.3%) of 2,181 patients, compared to no patients treated with placebo and 0.2% of patients treated with a comparative antidepressant.

The safety and efficacy of venlafaxine therapy in combination with weight loss agents, including phentermine, have not been established. Co-administration of ALTVEN and weight loss agents is not recommended. ALTVEN is not indicated for weight loss alone or in combination with other products.

Seizures

Seizures have been reported with venlafaxine therapy and in overdose. ALTVEN, as with all antidepressants, should be introduced with care, in patients with a history of seizure disorders. ALTVEN should be discontinued in any patient who develops seizures (see Overdosage).

Mania/Hypomania and Bipolar Disorder

Mania/hypomania may occur in a small proportion of patients with mood disorders treated with antidepressants, including venlafaxine.

A major depressive episode may be the initial presentation of bipolar disorder. It is generally believed (though not established in controlled trials) that treating such an episode with an antidepressant alone may increase the likelihood of precipitation of a mixed/manic episode in patients at risk for bipolar disorder. Whether any of the symptoms represent such a conversion is unknown. However, prior to initiating treatment with an antidepressant, patients with depressive symptoms should be adequately screened to determine if they are at risk for bipolar disorder; such screening should include a detailed psychiatric history, including a family history of suicide, bipolar disorder, and depression. It should be noted that ALTVEN is not approved for use in treating bipolar depression.

Aggression may occur in a small proportion of patients who have received antidepressants, including venlafaxine treatment, dose reduction or discontinuation.

Venlafaxine should be used cautiously in patients with a history of aggression.

Skin/Allergic Reactions

Patients should be advised to notify their physician if they develop a rash, hives, or related allergic phenomena.

Abnormal Bleeding

Drugs that inhibit serotonin uptake may lead to abnormalities of platelet aggregation. Bleeding abnormalities have been reported with venlafaxine ranging from skin and mucous membrane bleeding and gastrointestinal haemorrhage, to life-threatening haemorrhages. The risk may be increased in patients predisposed to bleeding, including patients on anti-coagulants and platelet inhibitors, and venlafaxine should be used cautiously in these patients.

Physical and Psychological Dependence

Clinical studies have shown no evidence of drug-seeking behaviour, development of tolerance, or dose escalation over time among patients taking venlafaxine. Consequently, physicians should carefully evaluate patients for a history of drug abuse and follow such patients closely observing them for signs of misuse or abuse of venlafaxine (e.g. development of tolerance, increase in dose, drug-seeking behaviour) (see Pharmacology).

Electroconvulsive Therapy

There are no clinical data establishing the benefit of ALTVEN combined with electroconvulsive therapy.

Use in Pregnancy

CATEGORY B2.

The safety of venlafaxine in human pregnancy has not been established. There are no adequate and well-controlled studies in pregnant women. Venlafaxine must be administered to pregnant women only if the expected benefits outweigh the possible risks. Patients should be advised to notify their physician if they become pregnant or intend to become pregnant during therapy. If venlafaxine is used until or shortly before birth, discontinuation effects in the newborn should be considered.

Some neonates exposed to venlafaxine, other SNRIs (Serotonin and Noradrenaline Reuptake Inhibitors), or SSRIs, late in the third trimester have developed complications requiring prolonged hospitalisation, respiratory support, or tube feeding. Such complications can arise immediately upon delivery. Reported clinical findings have included respiratory distress, cyanosis, apnoea, seizures, temperature instability, feeding difficulty, vomiting, hypoglycaemia, hypotonia, hypertonia, hyper-reflexia, tremor, jitteriness, irritability and constant crying. These features are consistent with either a direct toxic effect of SSRIs and SNRIs or, possibly, a drug discontinuation syndrome.

Epidemiological data have suggested that the use of SSRIs in pregnancy, particularly in late pregnancy, may increase the risk of persistent pulmonary hypertension in the new born (PPHN). Although no studies have investigated an association of PPHN to SNRI treatment, this potential risk cannot be ruled out with venlafaxine taking into account the related mechanism of action (inhibition of the re-uptake of serotonin).

Use in Lactation

Venlafaxine and/or its metabolites are secreted in milk of lactating rats at concentrations higher than those found in the plasma of the dam. Venlafaxine and its metabolites have been shown to pass into human milk. The total dose of venlafaxine and ODV ingested by breast fed infants can be as high as 9.2% of maternal intake. Therefore, the use of ALTVEN in nursing women cannot be recommended. Exposed infants should be observed closely.

Paediatric Use

ALTVEN is not indicated for use in children and adolescents younger than 18 years of age as safety and effectiveness has not been demonstrated. Therefore, ALTVEN should not be used in this age group.

In paediatric clinical trials, the adverse reaction, suicidal ideation, was observed. There were also increased reports of hostility and, especially in major depressive disorder, self-harm (see also Clinical Worsening and Suicide Risk above and Adverse Effects).

As with adults, decreased appetite, weight loss, increased blood pressure and increased serum cholesterol have been observed in children and adolescents aged 6 to 17 years (see Adverse Effects).

Use in the Elderly

No overall differences in effectiveness or safety were observed between elderly (aged 65 years and older) and younger patients. ALTVEN does not appear to pose any exceptional safety problems for healthy elderly patients.

Effectiveness in elderly patients with social anxiety disorder has not been established.

Use in Renal Impairment

The total daily dose of venlafaxine should be reduced by 25% to 50% for patients with renal impairment with a glomerular filtration rate (GFR) of 10 to 70 mL/min.

The total daily dose of venlafaxine should be reduced by 50% in haemodialysis patients.

Because of individual variability in clearance in these patients, individualisation of dosage may be desirable.

Use in Hepatic Impairment

The total daily dose of venlafaxine should be reduced by 50% in patients with mild to moderate hepatic impairment. Reductions of more than 50% may be appropriate for some patients.

Because of individual variability in clearance in these patients, individualisation of dosage may be desirable.

Carcinogenesis, Genotoxicity, Effects on Fertility

Carcinogenicity

Venlafaxine was given by oral gavage to mice and rats for 18 months and 24 months respectively, at dosages up to 120 mg/kg/day. There were no clear drug-related oncogenic effects in either species. In these studies, animal exposure to the main human metabolite ODV was less, and exposure to venlafaxine was more than would be expected in humans taking the recommended therapeutic and maximum doses.

Genotoxicity

There was no evidence of gene mutation or chromosomal change in a series of genotoxicity assays using venlafaxine and the main human metabolite ODV.

Effects on Fertility

Reproduction and fertility studies in rats showed no effects on male or female fertility at oral doses of up to 2 times the maximum recommended human dose on a mg/m2 basis.

Reduced fertility was observed in a study in which both male and female rats were exposed to the major metabolite of venlafaxine (ODV). This exposure was approximately 2 to 3 times that of a human venlafaxine dose of 225 mg/day. The human relevance of this finding is unknown.

Signs of pharmacological toxicity were seen in paternal and maternal rats given venlafaxine doses of 30 and 60 mg/kg/day, but no adverse effect was noted in fertility or general reproductive performance. Decreased fetal size and pup weight at birth with 60 mg/kg/day may be correlated with maternal toxicity.

Teratogenicity

In a rat teratology study, venlafaxine was given orally at dosages up to 80 mg/kg/day (approximately 11 times the maximum recommended human dose). Fetotoxicity evidenced by growth retardation was slightly increased at 80 mg/kg/day, an effect that may be related to maternal toxicity at this dose level. Fetal survival and morphologic development were not affected. In another teratology study, rabbits were given venlafaxine dosages up to 90 mg/kg/day. Fetotoxicity evidenced by resorption and fetal loss was slightly increased at 90 mg/kg/day (approximately 12 times the maximum recommended human dose). These effects could be correlated with maternal toxicity. No venlafaxine-associated teratogenic effect was noted in either species at any dosage, though there was an increased incidence of 'W'-shaped apex of the heart in the rabbit study. In these studies, animal exposure to the main human metabolite ODV was less, and estimated exposure to venlafaxine was approximately 6-fold more than would be expected in humans taking the recommended therapeutic and maximum doses. In rats, estimated exposure to venlafaxine was more than the expected human exposure. No teratogenic effect was seen.

In a perinatal toxicity study in rats after oral dosing of dams with 30 mg/kg or more, decreased pup survival following birth was observed. This effect is secondary to treatment-decreased maternal care, and is also seen with other antidepressants.

Effects on Ability to Drive and Use of Machines

Although venlafaxine has been shown not to affect psychomotor, cognitive or complex behaviour performance in healthy volunteers, any psychoactive medication may impair judgement, thinking or motor skills, and patients should be cautioned about operating hazardous machinery, including automobiles, until they are reasonably certain that the treatment does not affect them adversely.

Effects on Laboratory Tests

False-positive urine immunoassay screening tests for phencyclidine (PCP) and amphetamine have been reported in patients taking venlafaxine. This is due to lack of specificity of the screening tests. False positive test results may be expected for several days following discontinuation of venlafaxine therapy. Confirmatory tests, such as gas chromatography/mass spectrometry, will distinguish venlafaxine from PCP and amphetamine.

Interactions With Other Medicines

Venlafaxine and ODV are 27% and 30% bound to plasma proteins respectively; therefore interactions due to protein binding of venlafaxine and the major metabolite are not expected.

Monoamine Oxidase Inhibitors

Concomitant use of ALTVEN in patients taking monoamine oxidase inhibitors (MAOIs) or reversible MAOIs (e.g. moclobemide, linezolid and intravenous methylene blue) is contraindicated (see Contraindications).

Severe adverse reactions have been reported in patients who have recently been discontinued from a MAOI and started on venlafaxine, or have recently had venlafaxine therapy discontinued prior to initiation of a MAOI or when these two agents are co-administered. Reactions have included tremor, myoclonus, diaphoresis, nausea, vomiting, flushing, dizziness, hyperthermia with features resembling neuroleptic malignant syndrome and/or serotonergic syndrome, seizures, and death.

Do not take ALTVEN in combination with a MAOI or reversible MAOIs, or within at least 14 days of discontinuing MAOI treatment. Allow at least 7 days after stopping ALTVEN before starting a MAOI.

The appropriate washout period should take into account the pharmacological properties of venlafaxine, ODV and the MAOI and the clinician’s assessment of the individual patient.

CNS Active Drugs

The risk of using venlafaxine in combination with other CNS-active drugs has not been systematically evaluated. Consequently, caution is advised when venlafaxine is taken in combination with other CNS-active drugs.

Serotonin Syndrome

As with other serotonergic agents, serotonin syndrome, a potentially life threatening condition, may occur with venlafaxine treatment, particularly with concomitant use of other agents that may affect the serotonergic neurotransmitter system (including triptans, SSRIs, other SNRIs, lithium, sibutramine, fentanyl and its analogues, tramadol, dextromethorphan, tapentadol, pethidine, methadone or St John’s wort (Hypericum perforatum), with drugs which impair metabolism of serotonin (such as MAOIs including moclobemide, linezolid [an antibiotic which is a reversible non-selective MAOI] and intravenous methylene blue), or with serotonin precursors (such as tryptophan supplements). Serotonin syndrome symptoms may include mental status changes, autonomic instability, neuromuscular aberrations and/or gastrointestinal symptoms (see Contraindications and Precautions).

Serotonin syndrome has been reported in association with concomitant use with SSRIs. The decision to use venlafaxine in combination with SSRIs should include the advice of a psychiatrist.

If concomitant treatment of venlafaxine with an SSRI, an SNRI or a 5-hydroxytryptamine receptor agonist (triptan) is clinically warranted, careful observation of the patient is advised, particularly during treatment initiation and dose increases. The concomitant use of venlafaxine with serotonin precursors (such as tryptophan supplements) is not recommended (see Precautions).

As with other antidepressants, co-administration of ALTVEN and products containing St. John's wort (Hypericum perforatum) is not recommended due to possible pharmacodynamic interactions.

No information is available on the use of ALTVEN in combination with opiates.

There have been reports of elevated clozapine levels in association with adverse events including seizures, following the administration of venlafaxine.

Drugs that Prolong QT Interval

The risk of QTc prolongation and/or ventricular arrhythmias (e.g. TdP) is increased with concomitant use of other drugs which prolong the QTc interval (e.g. some antipsychotics and antibiotics) (see Precautions - QTc Prolongation/TdP).

Ethanol

Venlafaxine has not been shown to increase the impairment of mental and motor skills caused by ethanol. However, as with all CNS active drugs, patients should be advised to avoid alcohol consumption while taking ALTVEN.

Diazepam

The pharmacokinetic profiles of venlafaxine and ODV were not altered when venlafaxine and diazepam were administered together to healthy volunteers. Venlafaxine had no effect on the pharmacokinetics of diazepam or affect the psychomotor and psychometric effects induced by diazepam.

Lithium

The steady-state pharmacokinetics of venlafaxine and ODV are not affected when lithium is co-administered. Venlafaxine has no effect on the pharmacokinetics of lithium (see also CNS Active Drugs above). However, there have been reports of venlafaxine interaction with lithium resulting in increased lithium levels.

Haloperidol

Venlafaxine administered under steady-state conditions (75 mg twice daily) to 24 healthy subjects decreased total oral clearance (Cl/F) of a single 2 mg dose of haloperidol by 42%, which resulted in a 70% increase in haloperidol AUC. In addition, the haloperidol Cmax increased 88% when co-administered with venlafaxine, but the haloperidol elimination half-life (t½) was unchanged. The mechanism explaining this finding is unknown.

Risperidone

Venlafaxine increased risperidone AUC by 32% but did not significantly alter the pharmacokinetic profile of the total active moiety (risperidone plus 9-hydroxy-risperidone). The clinical significance of this interaction is unknown.

Indinavir

A pharmacokinetic study with indinavir has shown a 28% decrease in AUC and a 36% decrease in Cmax for indinavir. Indinavir did not affect the pharmacokinetics of venlafaxine and ODV. The clinical significance of this interaction is unknown.

Cimetidine

At steady-state cimetidine has been shown to inhibit the first-pass metabolism of venlafaxine but had no apparent effect on the formation or elimination of ODV, which is present in much greater quantity in the systemic circulation. The overall pharmacological activity of venlafaxine plus ODV is expected to increase only slightly in most patients. No dosage adjustment seems necessary when ALTVEN is co-administered with cimetidine. However, for elderly patients or patients with hepatic dysfunction, the interaction could potentially be more pronounced and for such patients clinical monitoring is indicated when ALTVEN is administered with cimetidine.

Metoprolol

Concomitant administration of venlafaxine (50 mg every 8 hours for 5 days) and metoprolol (100 mg every 24 hours for 5 days) to 18 healthy male subjects in a pharmacokinetic interaction study for both drugs resulted in an increase in the plasma concentrations of metoprolol by approximately 30-40% without altering the plasma concentrations of its active metabolite, α-hydroxymetoprolol. Metoprolol did not alter the pharmacokinetic profile of venlafaxine or its active metabolite, ODV.

Venlafaxine appeared to reduce the blood pressure lowering effect of metoprolol in this study. Caution should be exercised with co-administration of venlafaxine and metoprolol.

Venlafaxine treatment has been associated with dose-related increases in blood pressure in some patients. It is recommended that patients receiving ALTVEN have regular monitoring of blood pressure (see PrecautionsSustained Hypertension).

Antihypertensive and Hypoglycaemic Agents

Retrospective analysis of study events occurring in patients taking venlafaxine concurrently with antihypertensive or hypoglycaemic agents in clinical trials provided no evidence suggesting incompatibility between treatment with venlafaxine and treatment with either antihypertensive or hypoglycaemic agents.

Drugs Metabolised by Cytochrome P450 Isoenzymes

In vitro studies indicate that venlafaxine is a relatively weak inhibitor of CYP2D6 and that venlafaxine does not inhibit CYP1A2, CYP2C9 or CYP3A4. Some of these findings have been confirmed with drug interaction studies between venlafaxine and imipramine (metabolised by CYP2D6) and diazepam (metabolised by CYP2C19). Therefore, ALTVEN is not expected to interact with other drugs metabolised by these isoenzymes.

Imipramine

Venlafaxine did not affect the CYP2D6-mediated 2-hydroxylation of imipramine or its active metabolite, desimipramine, which indicates that venlafaxine does not inhibit the CYP2D6 isoenzyme. However, the renal clearance of 2-hydroxydesimipramine was reduced with co-administration of venlafaxine.

Imipramine partially inhibited the CYP2D6-mediated formation of ODV, however, the total concentrations of active compounds (venlafaxine plus ODV) was not affected with imipramine administration. Additionally, in a clinical study involving CYP2D6-poor and - extensive metabolisers, the total sum of the two active species (venlafaxine and ODV) was similar in the two metaboliser groups. Therefore, no dosage adjustment is expected when venlafaxine is co-administered with a CYP2D6 inhibitor. However, desipramine AUC, Cmax, and Cmin increased by about 35% in the presence of venlafaxine. There was an increase of 2-OH-desipramine AUC by 2.5 to 4.5 fold. The clinical significance of this finding is unknown.

Potential for Other Drugs to Affect Venlafaxine

The metabolic pathways for venlafaxine include CYP2D6 and CYP3A4.

In vitro and in vivo studies indicate that venlafaxine is metabolised predominantly to its active metabolite ODV by the cytochrome P450 enzyme CYP2D6, the isoenzyme that is responsible for the genetic polymorphism seen in the metabolism of many antidepressants. Therefore the potential exists for a drug interaction between drugs that inhibit CYP2D6-mediated metabolism (such as amiodarone and quinidine) and venlafaxine. CYP3A4 is a minor pathway relative to CYP2D6 in the metabolism of venlafaxine.

CYP2D6 Inhibitors

Concomitant use of CYP2D6 inhibitors and venlafaxine may reduce the metabolism of venlafaxine to ODV, resulting in increased plasma concentrations of venlafaxine and decreased concentrations of ODV. As venlafaxine and ODV are both pharmacologically active, no dosage adjustment is required when venlafaxine is co-administered with a CYP2D6 inhibitor.

CYP3A4 Inhibitors

Concomitant use of CYP3A4 inhibitors (such as erythromycin, fluconazole, ketoconazole and grapefruit juice) and venlafaxine may increase levels of venlafaxine and ODV. Therefore caution is advised when combining venlafaxine with a CYP3A4 inhibitor.

In vitro studies indicate that venlafaxine is likely metabolised to a minor, less active metabolite, N-desmethylvenlafaxine, by CYP3A4. A pharmacokinetic study with ketoconazole (a CYP3A4 inhibitor) in extensive metabolisers (EM) and poor metabolisers (PM) of CYP2D6 resulted in higher plasma concentrations of both venlafaxine and ODV in subjects following administration of ketoconazole. Venlafaxine Cmax increased by 26% in EM subjects and 48% in PM subjects. Cmax values for ODV increased by 14% and 29% in EM and PM subjects, respectively. Venlafaxine AUC increased by 21% in EM subjects and 70% in PM subjects. AUC values for ODV increased by 23% and 33% in EM and PM subjects, respectively.

CYP2D6 and CYP3A4 Inhibitors

The concomitant use of venlafaxine with drug treatment(s) that potentially inhibits both CYP2D6 and CYP3A4, the primary metabolising enzymes for venlafaxine, has not been studied. However, this concomitant use would be expected to increase venlafaxine plasma concentrations. Therefore caution is advised if a patient’s therapy includes venlafaxine and any agent(s) that produces simultaneous inhibition of these two enzyme systems. In patients with unstable heart disease receiving these combinations, assessment of the cardiovascular system (e.g. ECG; serum electrolytes during diuretic treatment) should be considered during treatment with venlafaxine (see Precautions - Use in Patients with Pre-Existing Heart Disease).

Adverse Effects

Clinical Trials

The information included in the adverse events clinical trials subsection are those that were observed in short-term, placebo-controlled studies with venlafaxine modified-release capsule and has been based on data from a pool of three 8- and 12-week controlled clinical trials in Major Depressive Disorder (dose range of 75 – 225 mg/day), on data up to 8 weeks from a pool of five controlled clinical trials in Generalised Anxiety Disorder with- venlafaxine modified-release capsule (dose range 37.5 – 225 mg/day), on data up to 12 weeks from a pool of five controlled clinical trials in Social Anxiety Disorder (dose range of 75 – 225 mg/day), and on data up to 12 weeks from a pool of four controlled clinical trials in Panic Disorder (dose range of 75 – 225 mg/day). (The adverse events occurring at an incidence ≥ 2% among venlafaxine modified-release capsule treated patients or at an incidence greater than the placebo treated patients are provided in the table below). The table shows the percentage of patients in each group who had at least one episode of an event at some time during the treatment. The prescriber should be aware that these figures cannot be used to predict the incidence of side effects in the course of usual medical practice where patient characteristics and other factors differ from those which prevailed in the clinical trials.

Adverse Event Incidence in Clinical Trials
Body SystemMajor Depressive Disorder1,5Generalised Anxiety Disorder2Social Anxiety Disorder3Panic Disorder4
Preferred termVenlafaxine-XR
n=357
Placebo
n=285
Venlafaxine-XR
n=1381
Placebo
n=555
Venlafaxine-XR
n=819
Placebo
n=695
Venlafaxine-XR
n=1001
Placebo
n=662
Body as a whole
Headache----38%34%--
Asthenia8%7%12%8%19%9%10%8%
Abdominal Pain----6%4%--
Accidental Injury----4%3%--
Cardiovascular
Hypertension4%1%--5%3%4%3%
Vasodilatation64%2%4%2%3%2%3%2%
Palpitation----3%1%--
Digestive
Nausea31%12%35%12%31%9%21%15%
Constipation8%5%10%4%9%3%9%3%
Anorexia78%4%8%2%17%2%8%3%
Vomiting4%2%5%3%3%3%--
Diarrhoea----8%6%--
Dyspepsia----7%6%--
Flatulance4%3%------
Metabolic/Nutritional
Weight loss3%0%--2%<1%--
Nervous
Dizziness20%9%16%11%16%8%11%10%
Somnolence17%8%14%8%20%8%12%6%
Insomnia17%11%15%10%24%8%17%9%
Dry Mouth12%6%16%6%17%4%12%6%
Nervousness10%5%6%4%10%5%--
Abnormal Dreams87%2%3%2%3%<1%--
Tremor5%2%4%<1%5%2%5%2%
Depression3%<1%------
Paraesthesia3%1%2%1%----
Libido decreased3%<1%4%2%8%2%4%2%
Agitation3%1%--3%1%--
Hypertonia--3%2%----
Anxiety----5%4%--
Twitching----3%<1%--
Respiratory
Pharyngitis7%6%------
Yawning3%p%3%<1%5%<1%--
Skin
Sweating14%3%10%3%13%4%10%2%
Special Senses
Abnormal Vision94%<1%5%<1%4%2%--
Urogential
Abnormal Ejaculation1016%<1%11%<1%19%<1%8%<1%
Impotence114%<1%5%<1%6%<1%4%<1%
Orgasmic Dysfunction123%<1%2%0%5%<1%2%<1%

1. Incidence, rounded to the nearest %, for events reported by at least 2% of patients treated with venlafaxine-XR, except the following events which had an incidence equal to or less than placebo: abdominal pain, accidental injury, anxiety, back pain, bronchitis, diarrhoea, dysmenorrhoea, dyspepsia, flu syndrome, headache, infection, pain, palpitation, rhinitis, and sinusitis.
2. Adverse events for which the venlafaxine-XR reporting rate was less than or equal to the placebo rate are not included. These events are: abdominal pain, accidental injury, anxiety, back pain, diarrhoea, dysmenorrhoea, dyspepsia, flu syndrome, headache, infection, myalgia, pain, palpitation, pharyngitis, rhinitis, tinnitus, and urinary frequency.
3. Adverse events for which the venlafaxine-XR reporting rate was less than or equal to the placebo rate are not included. These events are: arthralgia, back pain, dysmenorrhoea, flu syndrome, infection, pain, pharyngitis, rhinitis, and upper respiratory infection.
4. Adverse events for which the venlafaxine-XR reporting rate was less than or equal to the placebo rate are not included. These events are: abdominal pain, abnormal vision, accidental injury, anxiety, back pain, diarrhoea, dysmenorrhoea, dyspepsia, flu syndrome, headache, infection, nervousness, pain, paraesthesia, pharyngitis, rash, rhinitis, and vomiting.
5. <1% indicates an incidence greater than zero but less than 1%.
6. Mostly “hot flashes”.
7. Mostly “decreased appetite” and “loss of appetite”.
8. Mostly “vivid dreams”, “nightmare” and “increased dreaming”.
9. Mostly “blurred vision” and “difficulty focusing eyes”.
10. Males only – Mostly “delayed ejaculation”.
11. Incidence is based on number of male patients.
12. Females only – Mostly “delayed orgasm”, “abnormal orgasm” or “anorgasmia”.

The following table lists adverse reactions from combined analyses of the clinical studies for Major Depression, Generalised Anxiety Disorder, Social Anxiety Disorder, and Panic Disorder. The adverse reactions have been presented using the Council for International Organizations of Medical Sciences (CIOMS) frequency categories: Common: >1%; Uncommon: >0.1% and <1%; Rare: >0.01% and <0.1%; Very rare: <0.01%.

System Organ ClassAdverse Drug Reactions
General Disorders and Administration Site Conditions
Common:Asthenia, fatigue
Uncommon:Mucosal haemorrhage
Immune System Disorders
Rare:Anaphylactic reaction
Cardiac Disorders
Common:Tachycardia
Vascular Disorders
Common:Hypertension, hot flush
Uncommon:Hypotension, orthostatic hypotension
Gastrointestinal Disorders
Very common:Constipation, nausea, dry mouth
Common:Vomiting
Hepatobiliary Disorders
Uncommon:Liver function test abnormal
Blood and Lymphatic System Disorders
Rare:Thrombocytopenia
Endocrine Disorders
Rare:Inappropriate antidiuretic hormone secretion
Metabolism and Nutrition Disorders
Common:Decreased appetite
Uncommon:Hyponatraemia
Investigations
Common:Blood cholesterol increased, weight decreased, weight increased
Rare:Bleeding time prolonged
Musculoskeletal and Connective Tissue Disorders
Common:Hypertonia
Psychiatric Disorders
Very common:Insomnia
Common:Abnormal dreams, libido decreased, anorgasmia, nervousness
Uncommon:Mania, hypomania, hallucination, abnormal orgasm, bruxism, apathy
Nervous System Disorders
Very common:Dizziness, sedation
Common:Paraesthesia, tremor, dysgeusia
Uncommon:Syncope, myoclonus
Rare:Convulsion, neuroleptic malignant syndrome, serotonin syndrome
Respiratory, Thoracic and Mediastinal Disorders
Common:Yawning
Skin and Subcutaneous Tissue Disorders
Very common:Hyperhidrosis
Common:Rash
UncommonEcchymosis, photosensitivity reaction
Eye Disorders
Common:Accommodation disorder, mydriasis, visual impairment
Renal and Urinary Disorders
Common:Urinary hesitation, urinary retention
Reproductive System and Breast Disorders
Common:Ejaculation disorder, erectile dysfunction
Uncommon:Menorrhagia

Post-Marketing Reports

The following table lists adverse reactions derived from post-marketing spontaneous reports in patients with major depression, generalised anxiety disorder, social anxiety disorder and panic disorder. Adverse reactions are shown in CIOMS frequency categories: Common: >1%; Uncommon: >0.1% and <1%; Rare: >0.01% and <0.1%; Very rare: <0.01%; Unknown: cannot be estimated from the available data

System Organ ClassAdverse Drug Reactions
General Disorders and Administration Site Conditions
Common:Chills
Cardiac Disorder
Common:Palpitations
Rare:Electrocardiogram QT prolonged, ventricular fibrillation, ventricular tachycardia, torsade de pointes
Unknown:Stress cardiomyopathy
Gastrointestinal Disorders
Common:Diarrhoea
Uncommon:Gastrointestinal haemorrhage
Rare:Pancreatitis
Hepatobiliary Disorders
Rare:Hepatitis
Blood and Lymphatic System Disorders
Rare:Agranulocytosis, aplastic anemia, neutropenia, pancytopenia
Endocrine Disorders
Very rare:Blood prolactin increased
Musculoskeletal and Connective Tissue Disorders
Rare:Rhabdomyolysis
Psychiatric Disorders
Common:Agitation, confusional state, depersonalisation
Rare:Delirium
Nervous System Disorders
Very common:Headache
Common:Akathisia
Uncommon:Balance disorder, coordination abnormal, dyskinesia
Rare:Dystonia
Very rare:Tardive dyskinesia
Not known:Psychotic disorder, paranoia, aggression
Respiratory, Thoracic and Mediastinal Disorders
Common:Dyspnoea
Rare:Interstitial lung disease, pulmonary eosinophilia
Skin and Subcutaneous Tissue Disorders
Common:Pruritus, night sweats
Uncommon:Angioedema, urticaria, alopecia
Rare:Erythema multiforme, toxic epidermal necrolysis, Stevens-Johnson syndrome
Eye Disorders
Rare:Angle closure glaucoma
Ear and Labyrinth Disorders
Common:Tinnitus
Renal and Urinary Disorders
Common:Pollakiuria
Uncommon:Proteinuria, urinary incontinence
Reproductive System and Breast Disorders
Common:Metrorrhagia
Injury, poisoning and procedural complications
Uncommon:Bone fracture

Discontinuation Symptoms

Discontinuation effects are well known to occur with antidepressants, and it is therefore recommended that the dosage is tapered gradually and the patient monitored (see Dosageand Administration). The following symptoms have been reported in association with abrupt discontinuation or dose-reduction, or tapering of treatment: hypomania, anxiety, agitation, nervousness, confusion, insomnia or other sleep disturbances, fatigue, somnolence, paraesthaesia, dizziness, convulsion, vertigo, headache, flu-like symptoms, tinnitus, impaired coordination and balance, tremor, sweating, dry mouth, anorexia, diarrhoea, nausea, and vomiting. In pre-marketing studies, the majority of discontinuation reactions were mild and resolved without treatment.

In the Social Anxiety Disorder pooled short-term studies, the most common taper/post-study-emergent adverse events were dizziness (13%), nausea (7%), insomnia (3%), nervousness (3%) and asthenia (2%). In the 6-month study, the most common taper/post-study treatment emergent adverse events were dizziness (21% and 16%) and nausea (7% and 10%) for venlafaxine modified-release capsule 75 mg and 150-225 mg, respectively.

Paediatric Patients (see Precautions – Clinical Worsening and Suicide Risk and Paediatric Use)

In general, the adverse reaction profile of venlafaxine in placebo-controlled clinical trials in children and adolescents (aged 6 to 17) was similar to that seen in adults. As with adults, decreased appetite, weight loss, increased blood pressure and increased serum cholesterol were observed. Additionally, the following adverse reactions were observed: abdominal pain, agitation, dyspepsia, ecchymosis, epistaxis and myalgia. In paediatric clinical trials, there were increased reports of hostility and, especially in major depression, suicide-related adverse events such as suicidal ideation and self-harm.

Dosage and Administration

Major Depression, Generalised Anxiety Disorder and Social Anxiety Disorder

The usual recommended dose for the treatment of major depression, generalised anxiety disorder or social anxiety disorder is 75 mg per day given once daily. After two weeks, the dose may be increased to 150 mg per day given once daily if further clinical improvement is required. If needed, this can be increased up to 225 mg given once daily. Dose increments should be made at intervals of approximately 2 weeks or more, but not less than 4 days.

The recommended dose is based on results of clinical trials in which venlafaxine modified-release capsule was mostly given once daily in doses from 75 to 225 mg. Antidepressant activity with the 75 mg dose was observed after 2 weeks of treatment and anxiolytic activity was observed after one week.

It is recommended that ALTVEN be taken with food, at approximately the same time each day. Each capsule must be swallowed whole with fluid. Do not divide, crush, chew, or dissolve. ALTVEN should be administered once daily.

Panic Disorder

The recommended dose is 75 mg of ALTVEN once daily. Treatment should be started with a dose of 37.5 mg per day of ALTVEN for the first 4 to 7 days, after which the dose should be increased to 75 mg once daily.

Patients not responding to the 75 mg/day dose may benefit from dose increases to a maximum of 225 mg/day, although there is no direct clinical trial evidence of any significant increase in efficacy with increase in dose. Dosage increases can be made in increments of 75 mg per day at intervals of approximately 2 weeks or more, but not less than 4 days.

Dosage Adjustment in Renal or Hepatic Impairment

Patients with renal and/or hepatic impairment should receive lower doses of ALTVEN. The total daily dose of venlafaxine should be reduced by 25% to 50% in patients with renal impairment with a glomerular filtration rate (GFR) of 10 to 70 mL/min. Haemodialysis clearances of both venlafaxine and ODV in humans are low. The total daily dose of venlafaxine should be reduced by 50% in haemodialysis patients.

Patients with mild to moderate hepatic impairment should also have their dosage reduced by 50%. Further reductions in dosage should be considered for patients with more severe degrees of hepatic impairment.

Because of individual variability in clearance in these patients, individualisation of dosage may be desirable.

Dosage Adjustment in the Elderly

No adjustment in the usual dose is recommended for elderly patients solely because of their age. As with any antidepressant, however, caution should be exercised in treating the elderly. When individualising the dosage, extra care should be taken when increasing the dose.

Maintenance/Continuation/Extended Treatment

The physician should periodically re-evaluate the usefulness of long-term ALTVEN treatment for the individual patient. It is generally agreed that acute episodes of major depression require several months or longer of sustained pharmacological therapy. Whether the dose of antidepressant needed to induce remission is identical to the dose needed to maintain and/or sustain euthymia is unknown.

Usually, the dosage for prevention of relapse or for prevention of recurrence of a new episode is similar to that used during initial treatment. Patients should be regularly re-assessed in order to evaluate the benefit of long-term therapy.

In Social Anxiety Disorder, continuing therapeutic benefit has been established for periods of up to 6 months. The need for continuing medication in patients with Social Anxiety Disorder who improve with ALTVEN treatment should be periodically assessed.

It is generally agreed that acute episodes of panic disorder require several months or longer of sustained pharmacological therapy beyond response to the acute episode. Longer-term efficacy was demonstrated in one study (Study 5) in which patients responding during 12 weeks of acute treatment with venlafaxine modified-release capsule were assigned randomly to placebo or to the same dose of venlafaxine modified-release capsule (75, 150, or 225 mg/day) during 6 months of maintenance treatment as they had received during the acute stabilization phase (see Clinical Trials – Panic Disorder).

Discontinuing Altven

When ALTVEN at a dose of 75 mg/day or greater has been administered for more than 1 week is stopped, it is recommended whenever possible that the dose be tapered gradually to minimise the risk of discontinuation symptoms. In clinical trials with venlafaxine modified-release capsule, tapering was achieved by reducing the daily dose by 75 mg at 1 week intervals. To facilitate tapering below 75 mg of ALTVEN, physicians may consider prescribing the 37.5 mg capsules once daily (see also Major Depression, GeneralisedAnxiety Disorder and Social Anxiety Disorder above). The period required for tapering may depend on the dose, duration of therapy, and the individual patient. Patients should be advised to consult their physician before abruptly discontinuing ALTVEN.

Overdosage

In managing overdosage, consider the possibility of multiple medication involvement (see Interactions With Other Medicines).

The physician should consider contacting the Poison Information Centre on 13 11 26 for advice on the treatment of any overdose.

Signs and Symptoms

During pre-marketing trials, most patients who have overdosed with venlafaxine were asymptomatic. Of the remainder, somnolence was the most commonly reported symptom. Mild sinus tachycardia and mydriasis have also been reported. There were no reports of seizures, respiratory distress, significant cardiac disturbances, or significant laboratory test result abnormalities among any of the cases reported to date. However, seizures and respiratory distress occurred in one patient in an on-going study who ingested an estimated 2.75g of venlafaxine with naproxen and thyroxine. Generalised convulsions and coma resulted and emergency resuscitation was required. Recovery was good without sequelae.

In post-marketing experience, overdose with venlafaxine was reported predominantly in combination with alcohol and/or other drugs. The most commonly reported events in overdose include tachycardia, changes in level of consciousness (ranging from somnolence to coma), mydriasis, vomiting and seizures. Other events reported included electrocardiogram changes (e.g. prolongation of QT interval, bundle branch block, QRS prolongation), ventricular fibrillation, ventricular tachycardia (including torsade de pointes), bradycardia, hypotension, vertigo, and death. Serotonin toxicity has been reported in association with venlafaxine overdose.

Fatal Overdoses

Published retrospective analyses from the United Kingdom (UK) report the rate of antidepressant overdose deaths per million prescriptions. In these analyses, the rate for venlafaxine is higher than that for SSRIs, but lower than that for tricyclic antidepressants. These analyses did not adjust for suicide risk factors. Epidemiological studies have shown that venlafaxine is prescribed to patients with a higher pre-existing burden of suicide risk factors than patients prescribed SSRIs. The extent to which the finding of an increased risk of fatal outcomes can be attributed to the toxicity of venlafaxine in overdosage as opposed to some characteristics of venlafaxine-treated patients is not clear. Prescriptions of venlafaxine should be written for the smallest quantity of drug consistent with good patient management, in order to reduce the risk of overdose (see Precautions - Clinical Worsening andSuicide Risk).

Management of Overdosage

General supportive and symptomatic measures are recommended. Ensure an adequate airway, oxygenation and ventilation. Cardiac rhythm and vital signs must be monitored. Administration of activated charcoal may also limit drug absorption. Where there is a risk of aspiration, induction of emesis is not recommended. No specific antidotes for venlafaxine are known. Forced diuresis, dialysis, haemoperfusion and exchange transfusion are unlikely to be of benefit. Venlafaxine and ODV are not considered dialyzable because haemodialysis clearance of both compounds is low.

Presentation and Storage Conditions

ALTVEN modified release capsules are available for oral use as:

37.5 mg, grey cap/peach body with ‘W’ on the cap and “37.5” on the body.

75 mg, peach cap and body with ‘W’ on the cap and “75” on the body.

150 mg, dark orange cap and body with ‘W’ on the cap and “150” on the body.

ALTVEN 37.5 mg, 75 mg and 150 mg are packed in blister packs in pack sizes# of 7, 14 and 28.

# Not all presentations are available.

Storage

Store below 30°C.

Name and Address of the Sponsor

Pfizer Australia Pty Ltd
ABN 50 008 422 348
38-42 Wharf Road
WEST RYDE NSW 2114

Poison Schedule of the Medicine

S4, PRESCRIPTION ONLY MEDICINE