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

Manufacture: Sunovion Pharmaceuticals Inc.
Country: Canada
Condition: High Cholesterol, Hyperlipoproteinemia Type V, Elevated Chylomicrons VLDL, Hyperlipoproteinemia Type IV, Elevated VLDL, Hyperlipoproteinemia
Class: Miscellaneous antihyperlipidemic agents, Vitamins
Form: Tablets
Ingredients: extended-release niacin, methylcellulose, povidone, stearic acid

Summary product information

Route of
Administration
Dosage Form / StrengthClinically Relevant Nonmedicinal
Ingredients
oral500 mg and 1000 mg
extended-release tablets
methylcellulose, povidone, stearic acid

Indications and clinical use

NIASPAN (extended-release niacin) is indicated as an adjunct to diet for reduction of elevated total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), apolipoprotein B (Apo B) and triglyceride (TG) levels, and to increase high-density lipoprotein cholesterol (HDL-C) in patients with primary hypercholesterolaemia (heterozygous familial and nonfamilial) and mixed dyslipidaemia (Frederickson Types IIa and IIb), when the response to an appropriate diet and other non-pharmacological measures have been inadequate.

Therapy with NIASPAN should be only one component of multiple risk factor intervention in individuals at significantly increased risk for atherosclerotic vascular disease due to hypercholesterolemia. Prior to initiating therapy with NIASPAN, secondary causes for hypercholesterolemia (e.g., poorly controlled diabetes mellitus, hypothyroidism, nephrotic syndrome, dysproteinemias, obstructive liver disease, other drug therapy, alcoholism) should be excluded, and a lipid profile obtained to measure TC, HDL-C, and TG.

Pediatrics:

No studies in patients under 21 years of age have been conducted with NIASPAN.

Contraindications

  • NIASPAN (extended-release niacin) is contraindicated in patients with a known hypersensitivity to niacin or any component of this medication (see DOSAGE FORMS - COMPOSITION AND PACKAGING).
  • Active liver disease or unexplained persistent elevations of serum transaminases, active peptic ulcer, or active bleeding.

Warnings and precautions

Serious Warnings and Precautions
  • NIASPAN (extended-release niacin) preparations should not be substituted for equivalent doses of immediate-release (crystalline) niacin or nicotinic acid. For patients switching from immediate-release niacin or nicotinic acid to NIASPAN, therapy with NIASPAN should be initiated with low doses (i.e., 500 mg qhs) and the NIASPAN dose should then be titrated to the desired therapeutic response.
  • Cases of severe hepatic toxicity, including fulminant hepatic necrosis, have occurred in patients who have substituted sustained-release (modified-release, timed-release) niacin products for immediate-release (crystalline) niacin at equivalent doses.

Clinically significant warnings and precautions are listed below in alphabetical order.

General

Before instituting therapy with NIASPAN, an attempt should be made to control hyperlipidaemia with appropriate diet, exercise, and weight reduction in obese patients, and to treat other underlying medical problems (see INDICATIONS AND CLINICAL USE).

While pretreatment with acetylsalicylic acid (ASA) or other non-steroidal anti-inflammatory drugs (NSAIDs) may reduce flushing of the skin, some patients should not take these medications (e.g., patients who have peptic ulcer or active inflammatory disease of the gastrointestinal system or ASA hypersensitivity; refer to the Product Monograph for the NSAID product).

Concomitant Use with HMG-CoA Reductase Inhibitors (statins)

NIASPAN has not been shown to reduce cardiovascular morbidity or mortality among patients already treated with a statin.

Addition of NIASPAN FCT did not reduce cardiovascular morbidity or mortality among patients treated with simvastatin in a large, randomized controlled trial (AIM-HIGH) and a significant excess of bleeding, serious infections, blood glucose increase and new onset of diabetes mellitus were reported (see WARNINGS AND PRECAUTIONS, Endocrine and Metabolism, Increase in Blood Glucose and ADVERSE REACTIONS).

Cardiovascular

Data on the safety and efficacy of NIASPAN in patients with unstable angina or in the acute phase of myocardial infarction are not available. Therefore, caution should be used when NIASPAN is used, particularly when such patients are also receiving vasodilator agents.

Endocrine and Metabolism

Increase in Blood Glucose

Niacin treatment can increase fasting blood glucose. Frequent monitoring of blood glucose should be performed to ascertain that the drug is producing no adverse effects. Diabetic patients may experience a dose-related increase in glucose intolerance. Diabetic or potentially diabetic patients with hypercholesterolaemia should be observed closely during treatment with NIASPAN, particularly during the first few months of use or dose adjustment; adjustment of diet and/or hypoglycemic therapy may be necessary (see ADVERSE DRUG REACTIONS).

Uric Acid

Elevated uric acid levels have occurred with niacin therapy, therefore use with caution in patients predisposed to gout.

Phosphorus

In placebo-controlled trials, NIASPAN has been associated with small but statistically significant, dose-related reductions in phosphorus levels (mean of -13% with 2000 mg). Although these reductions were transient, phosphorus levels should be monitored periodically in patients at risk for hypophosphatemia.

Gastrointestinal

Patients with a past history of jaundice or peptic ulcer should be observed closely during NIASPAN therapy.

Hematologic

NIASPAN has been associated with small, but statistically significant dose-related reductions in platelet count (mean of -11% with 2000 mg). In addition, NIASPAN has been associated with small but statistically significant increases in prothrombin time (mean of approximately +4% with 2000 mg); accordingly, patients undergoing surgery should be carefully evaluated. Caution should be observed when NIASPAN is administered concomitantly with anticoagulants; prothrombin time and platelet counts should be monitored closely in such patients.

Hepatic/Biliary/Pancreatic

No clinical studies have been carried out in patients with impaired liver function.

Patients with a past history of jaundice, hepatobiliary disease, or peptic ulcer should be observed closely during NIASPAN therapy. Frequent monitoring of liver function tests should be performed.

NIASPAN should be used with caution in patients who consume substantial quantities of alcohol and/or have a past history of liver disease

Niacin preparations have been associated with abnormal liver tests. In three placebo-controlled clinical trials involving titration to final daily NIASPAN doses ranging from 500 to 3000 mg, 245 patients received NIASPAN for a mean duration of 17 weeks and no patient with normal serum transaminase levels (AST, ALT) at baseline experienced elevations to more than 3 times the upper limit of normal (ULN). In these studies, fewer than 1% (2/245) of NIASPAN patients discontinued due to transaminase elevations greater than 2 times the ULN.

In three safety and efficacy studies with a combination tablet of NIASPAN and lovastatin involving titration to final daily doses (expressed as mg of extended-release niacin/mg of lovastatin) 500mg/10mg to 2500mg/40mg, ten of 1028 patients (1.0%) experienced reversible elevations in AST/ALT to more than 3 times the upper limit of normal (ULN). Three of ten elevations occurred at doses outside the recommended dosing limit of 2000mg/40mg; no patient receiving 1000mg/20mg had 3-fold elevations in AST/ALT.

In the placebo-controlled clinical trials and the long-term extension study, elevations in transaminases did not appear to be related to treatment duration. However, elevations in AST levels did appear to be dose related. Transaminase elevations were reversible upon discontinuation of NIASPAN.

Renal

No clinical studies have been carried out in patients with impaired renal function. Niacin and its metabolites are excreted through the kidneys. NIASPAN should be used with caution in patients with renal dysfunction.

Skeletal Muscle

Rare cases of rhabdomyolysis have been associated with concomitant administration of lipid- altering doses (≥ 1 g/day) of niacin and HMG-CoA reductase inhibitors. In clinical studies with a combination tablet of NIASPAN and lovastatin, no cases of rhabdomyolysis and one suspected case of myopathy have been reported in 1079 patients who were treated with doses up to 2000mg of NIASPAN and 40mg of lovastatin daily for periods up to 2 years. Physicians contemplating combined therapy with HMG-CoA reductase inhibitors and NIASPAN should carefully weigh the potential benefits and risks and should carefully monitor patients for any signs and symptoms of muscle pain, tenderness, or weakness, particularly during the initial months of therapy and during any periods of upward dosage titration of either drug (see DRUG INTERACTIONS). Periodic serum creatine phosphokinase (CPK) and potassium determinations should be carried out, but there is no assurance that such monitoring will prevent the occurrence of severe myopathy.

Special Populations

Pregnant Women

No information is available on the safety of NIASPAN in pregnant women. Animal reproduction studies have not been conducted with niacin or with NIASPAN. It is not known whether niacin at doses used for lipid disorders can cause fetal harm when administered to pregnant women or whether it can affect reproductive capacity. If a woman receiving treatment with NIASPAN becomes pregnant, the drug should be discontinued.

Nursing Women

No information is available on the safety of NIASPAN in nursing women. Niacin has been reported to be excreted in human milk. Because of the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug.

Pediatrics

Safety and effectiveness of niacin therapy in pediatric patients have not been established. No studies in patients under 21 years of age have been conducted with NIASPAN.

Geriatrics

No formal studies have been carried out in elderly patients. Patients up to 75 years of age participated in controlled clinical trials of NIASPAN.

Monitoring and Laboratory Tests

Liver tests should be performed on all patients during therapy with NIASPAN. Serum transaminase levels, including AST and ALT (SGOT and SGPT), should be monitored before treatment begins, every 6 to 12 weeks for the first year, and periodically thereafter (e.g., at 6 month intervals). Special attention should be paid to patients who develop elevated serum transaminase levels. In these patients, measurements should be repeated promptly and then performed more frequently. If the transaminase levels show evidence of progression, particularly if they rise to 3 times ULN and are persistent, or if they are associated with symptoms of nausea, fever, and/or malaise, the drug should be discontinued.

Adverse reactions

Adverse Drug Reaction Overview

The most frequently-reported events with NIASPAN (extended-release niacin) are flushing episodes, which generally become less common as treatment progresses and which may be reduced by concomitant acetylsalicylic acid (ASA) therapy and by following the recommended dose titration schedule (see WARNINGS AND PRECAUTIONS, General).

In the placebo-controlled clinical trials, flushing episodes (i.e., warmth, redness, itching and/or tingling) were the most common treatment-emergent adverse events for NIASPAN, reported in up to 88% of patients. Spontaneous reports suggest that flushing may also be accompanied by symptoms of dizziness, tachycardia, palpitations, shortness of breath, sweating, chills, and/or edema, which in rare cases may lead to syncope. In pivotal studies, fewer than 6% (14/245) of NIASPAN patients discontinued due to flushing. Following 4 weeks of maintenance therapy with NIASPAN at daily doses of 1500 mg, the incidence of flushing over the 4-week period averaged 8.56 events per patient for IR niacin versus 1.88 events per NIASPAN patient.

Other commonly reported non-serious events include gastrointestinal symptoms and rash. The majority of adverse events reported were mild and transient.

In general, the incidence of adverse events was higher in women compared to men.

Niacin therapy has been associated with abnormalities of liver function. In patients receiving NIASPAN, liver function should be periodically monitored.

Clinical Trial Adverse Drug Reactions

Because clinical trials are conducted under very specific conditions the adverse reaction rates observed in the clinical trials may not reflect the rates observed in practice and should not be compared to the rates in the clinical trials of another drug. Adverse drug reaction information from clinical trials is useful for identifying drug-related adverse events and for approximating rates.

Based on the experience in a total of 723 patients, of whom 477 were treated with NIASPAN for one year (48 weeks) and 379 for 2 years (96 weeks), the majority of adverse events were mild and transient.

Adverse events occurring at an incidence of ≥ 2% in patients treated with NIASPAN during premarketing controlled studies are shown in Table 1 by body system.

Table 1 - Treatment-Emergent Adverse Events by Dose Level in  2% of Patients and at an Incidence Greater than
PLACEBO-CONTROLLED STUDIES
Placebo NIASPAN
(All Doses)
Total # of Patients157245
Body As a Whole
Asthenia3%4%
Chills1%3%
Fever3%7%
Flu Syndrome5%7%
Pain, Abdominal6%8%
Pain, Back7%9%
Pain, Chest2%6%
Surgical Procedure1%2%
Cardiovascular System
Migraine1%2%
Palpitation1%3%
Tachycardia02%
Digestive System
Diarrhea13%20%
Dyspepsia12%13%
Eructation1%2%
Nausea7%13%
Vomiting4%7%
Metabolism and Nutritional Disorders
Edema1%2%
Edema, Peripheral02%
Musculoskeletal System.
Arthralgia03%
Arthritis2%3%
Nervous System
Dry Mouth02%
Somnolence1%2%
Respiratory System
Cough, Increase6%7%
Rhinitis31%34%
Skin and Appendages
Pruritus2%6%
Rash1%7%
Skin Discoloration1%3%
Sweating1%2%
Urticaria1%2%
Special Senses
Tinnitus1%2%

Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglycerides: Impact on Global Health Outcomes (AIM-HIGH)

In AIM-HIGH involving 3414 patients (mean age of 64 years, 15% women, 92% Caucasians, 34% with diabetes mellitus) with stable, previously diagnosed cardiovascular disease, all patients received simvastatin, 40 to 80 mg/day, plus ezetimibe 10 mg/day if needed, to maintain an LDL- C level of approximately 1-2 mmol/L and were randomized to receive NIASPAN FCT 1500- 2000 mg/day (n=1718) or matching placebo (immediate release niacin, 100-150 mg, n=1696).

Serious adverse events were reported in 34.2% of patients receiving simvastatin plus NIASPAN FCT and 32.5% of patients receiving simvastatin plus placebo. Serious adverse events reported significantly more frequently in patients receiving simvastatin plus NIASPAN FCT included vomiting (1.2% vs. 0.5%), appendicitis (0.5% vs. 0.1%), cellulitis (1.5% vs. 0.8%), and abdominal pain (1.3% vs. 0.6%).

In an ITT analysis, there were 42 cases of first occurrence of ischemic stroke reported, 27 (1.6%) in the simvastatin plus NIASPAN FCT group and 15 (0.9%) in the simvastatin plus placebo group, a non-statistically significant result (HR 1.79, [95%CI = 0.95-3.36], p=0.071). The on- treatment ischemic stroke events were 19 for the simvastatin plus NIASPAN FCT group and 15 for the simvastatin plus placebo group.

A significant increase in the frequency of other adverse reactions consistent with the known effects of niacin and other lipid modifiers were observed in the simvastatin plus NIASPAN FCT group compared to the simvastatin plus placebo group, including blood glucose increased (6.6% vs. 4.7%), diabetes mellitus (4.0% vs. 2.5%), hyperglycemia (1.6% vs. 0.6%), liver function test abnormal (0.4% vs. 0%), thrombocytopenia (0.9% vs. 0.2%) and gastrointestinal events, including diarrhea (8.4% vs. 4.0%) and vomiting (3.7% vs. 2.1%).

There were 5 cases of rhabdomyolysis reported, 4 (0.2%) in the simvastatin plus NIASPAN FCT group and one (<0.1%) in the simvastatin plus placebo group.

Overall adverse events related to System Organ Classes of “hemorrhagic events” (10.1% vs. 8.1%) and “infections and infestations” (39.2% vs. 35.0%) were observed more frequently among patients assigned to the simvastatin plus NIASPAN FCT group than among those assigned to the simvastatin plus placebo group. Within these System Organ Classes, rectal hemorrhage (1.1% vs. 0.5%), epistaxis (1.9% vs. 0.9%) and herpes zoster (3.1% vs. 1.8%) were more frequent among patients receiving simvastatin plus NIASPAN FCT.

Less Common Adverse Drug Reactions (<2%)

The following adverse events have been reported with NIASPAN or other niacin products, either during clinical trials or in routine patient management, irrespective of causality.

Body as a Whole: enlarged abdomen, cyst, hernia, mucous membrane disorder, face edema

Cardiovascular: angina pectoris, cardiovascular disorder, hemorrhage, atrial fibrillation and other cardiac arrhythmias, hypotension, orthostasis, syncope

Digestive: cholelith, dysphagia, esophagitis, GI hemorrhage, fecal incontinence, stomatitis, tongue disorder, flatulence, activation of peptic ulcers and peptic ulceration, jaundice

Hemic and Lymphatic: leucopenia

Hypersensitivity Reactions: An apparent hypersensitivity reaction has been reported rarely that has included one or more of the following features: anaphylaxis, angioedema, urticaria, flushing, dyspnea, tongue edema, larynx edema, face edema, peripheral edema, laryngismus, and vesiculobullous rash, hypotension and circulatory collapse.

Metabolism and Nutritional Disorders: bilirubinemia, xanthoma, decreased glucose tolerance, anorexia, gout

Musculoskeletal: bone disorder, bursitis, myasthenia, rhabdomyolysis, myalgia, myopathy

Nervous: hypertonia, hypesthesia, hypokinesia, increased libido, twitch, vertigo, leg cramps; nervousness; paresthesia, dizziness, headache, insomnia

Respiratory: bronchitis, hemoptysis, hyperventilation, laryngitis, lung disorder, dyspnea

Skin and Appendages: acne, alopecia, application site reaction, contact dermatitis, fungal dermatitis, eczema, herpes zoster, skin neoplasm, vesiculobullous rash, dry skin, skin ulcer, general exanthema, hyperpigmentation, acanthosis nigricans, maculopapular rash

Special Senses: eye disorder, glaucoma, vision abnormal, toxic amblyopia, cystoid macular edema

Urogenital: impotence, breast pain, polyuria, prostatic disorder, UG disorder, urinary retention, vaginitis.

Abnormal Hematologic and Clinical Chemistry Findings

Chemistry: Elevations in serum transaminases (see WARNINGS AND PRECAUTIONS, Hepatic/Biliary/Pancreatic), LDH, fasting glucose, uric acid, total bilirubin, and amylase; reductions in phosphorus.

Hematology: Slight reductions in platelet counts and prolongation in prothrombin time (see WARNINGS AND PRECAUTIONS, Hematologic).

Post-Market Adverse Drug Reactions

In post-market safety surveillance, flushing, headache, tachycardia, asthenia, insomnia, and maculopapular rash were the most frequently reported non-serious adverse events.

Drug interactions

Overview

HMG-CoA Reductase Inhibitors

Rhabdomyolysis has been rarely reported in patients receiving niacin concomitantly with an HMG-CoA reductase inhibitor (statin) (see WARNINGS AND PRECAUTIONS and ADVERSE REACTIONS).

In a clinical trial of extended-release niacin and laropiprant (median follow-up 3.9 years) involving patients at high risk of cardiovascular disease and with well-controlled LDL-C levels on simvastatin 40 mg/day with or without ezetimibe 10 mg, the incidence of myopathy was approximately 0.24% for Chinese patients on simvastatin 40 mg or ezetimibe/simvastatin1 10/40 mg compared with 1.24% for Chinese patients on simvastatin 40 mg or ezetimibe/simvastatin1 10/40 mg coadministered with extended-release niacin/laropiprant1 2 g/40 mg. While the only Asian population assessed in this clinical trial was Chinese, and the incidence of myopathy is higher in Chinese than in non-Chinese patients, coadministration of simvastatin with lipid-modifying doses (1 g/day) of niacin is not recommended in Asian patients.

Alcohol or hot drinks taken at the time of NIASPAN (extended-release niacin) administration may worsen the flushing response and pruritus.

Antihypertensive Therapy

Niacin may potentiate the effects of ganglionic blocking agents and vasoactive drugs resulting in postural hypotension.

Acetylsalicylic acid (ASA): Concomitant administration of ASA may decrease the metabolic clearance of niacin (see WARNINGS AND PRECAUTIONS, General).

Bile-Acid Sequestrants

An interval of 4 to 6 hours, or as great an interval as possible, should elapse between the ingestion of bile acid-binding resins and the administration of NIASPAN. An in vitro study showed that about 98% of available niacin was bound to colestipol, and 10 to 30% was bound to cholestyramine.

Other

Vitamins or other nutritional supplements containing large doses of niacin or related compounds such as nicotinamide may potentiate the adverse effects of NIASPAN.

Drug-Food Interactions

Concomitant alcohol or hot drinks may increase the side effects of flushing and pruritus and should be avoided around the time of NIASPAN ingestion.

Drug-Herb Interactions

Interactions with herbal products have not been studied.

Drug-Laboratory Interactions

Niacin may produce false elevations in some fluorometric determinations of plasma or urinary catecholamines. Niacin may also give false-positive reactions with cupric sulfate solution (Benedict’s reagent) in urine glucose tests.

Dosage and administration

Patients should be placed on a standard cholesterol-lowering diet at least equivalent to the NCEP Adult Treatment Panel III TLC diet before receiving NIASPAN (extended-release niacin) and should continue on this diet during treatment with NIASPAN. If appropriate, a program of weight control and physical exercise should be implemented.

Dosing Considerations

  • Equivalent doses of NIASPAN should not be substituted for immediate-release (crystalline) niacin.
  • NIASPAN tablet strengths are not interchangeable.
  • Women may respond at lower NIASPAN doses than men.
  • Flushing of the skin may be reduced in frequency or severity by pretreatment with acetylsalicylic acid and avoiding administration on an empty stomach (see WARNINGS AND PRECAUTIONS, General).
  • NIASPAN is contraindicated in patients with significant or unexplained hepatic dysfunction.
  • No information is available on the safety of NIASPAN in patients with renal insufficiency.

Recommended Dose and Dosage Adjustment

NIASPAN should be taken at bedtime, after a low-fat snack, and doses should be individualized according to patient response. Therapy with NIASPAN must be initiated at 500 mg at bedtime, in order to reduce the incidence and severity of side effects which may occur during early therapy. The recommended dose escalation is shown in Table 2 below.

Table 2 - Recommended Dosing
Week(s) Daily dose
INITIAL TITRATION
SCHEDULE
1 to 4
5 to 8
500 mg
1000 mg
FURTHER
TITRATION
SCHEDULE *
After Week 8 1500 mg
2000 mg

* After Week 8, titrate to patient response and tolerance. If response to 1000 mg daily is inadequate, increase dose to 1500 mg daily; may subsequently increase dose to 2000 mg daily. Daily dose should not be increased more than 500 mg in a 4-week period, and doses above 2000 mg daily are not recommended.

Maintenance Dose:

The daily dosage of NIASPAN should not be increased by more than 500 mg in any 4-week period. The initial recommended maintenance dose is 1000 mg once daily at bedtime with further titration to 2000 mg depending on patient response. Doses greater than 2000 mg daily are not recommended.

The tablet strengths of NIASPAN are not interchangeable. Do not alternate between different strengths to provide the same daily dosage. The physician should specify the tablet strengths that the patient should use during titration and continue to use for maintenance therapy.

Women may respond at lower NIASPAN doses than men (see ACTION AND CLINICAL PHARMACOLOGY, Special Populations and Conditions, Sex).

If lipid response to NIASPAN alone is insufficient or if higher doses of NIASPAN are not well tolerated, some patients may benefit from combination therapy with a bile acid binding resin or an HMG CoA reductase inhibitor (see WARNINGS AND PRECAUTIONS, Drug Interactions).

Flushing of the skin (see Adverse Reactions) may be reduced in frequency or severity by pretreatment with ASA (taken 30 minutes prior to NIASPAN dose) or non-steroidal anti- inflammatory drugs. Tolerance to this flushing develops rapidly over the course of several weeks. Flushing, pruritus, and gastrointestinal distress are also greatly reduced by slowly increasing the dose of NIASPAN and avoiding administration on an empty stomach (see WARNING AND PRECAUTIONS, General).

Equivalent doses of NIASPAN should not be substituted for sustained-release (modified- release, timed-release) niacin preparations or immediate-release (crystalline) niacin and visa versa (see WARNINGS AND PRECAUTIONS). This should be explained to patients.Patients previously receiving other niacin products should be started with the recommended NIASPAN titration schedule (see Table 2).

If NIASPAN therapy is discontinued for an extended period, reinstitution of therapy should include a titration phase (see Table 2).

Dosage in Patients with Renal Insufficiency:

Use of NIASPAN in patients with renal insufficiency has not been studied. No information is available regarding the safety of NIASPAN use in patients with renal insufficiency.

Dosage in Patients with Hepatic Insufficiency:

Use of NIASPAN in patients with hepatic insufficiency has not been studied. NIASPAN is contraindicated in patients with significant or unexplained hepatic dysfunction (see CONTRAINDICATIONS).

Missed Dose

If a dose of this medication is missed, it is not necessary to make up the missed dose. Skip the missed dose and continue with the next scheduled dose. Do not double doses.

Administration

NIASPAN tablets should be taken whole and should not be broken, crushed or chewed before swallowing.

Overdosage

Supportive measures should be undertaken in the event of an overdose.

Action and clinical pharmacology

Mechanism of Action

The mechanism by which niacin alters lipid profiles has not been well defined. It may involve several actions including partial inhibition of release of free fatty acids from adipose tissue, and increased lipoprotein lipase activity, which may increase the rate of chylomicron triglyceride removal from plasma. Niacin decreases the rate of hepatic synthesis of VLDL and LDL, and does not appear to affect fecal excretion of fats, sterols, or bile acids.

Pharmacodynamics

Niacin functions in the body after conversion to nicotinamide adenine dinucleotide (NAD) in the NAD coenzyme system. Niacin (but not nicotinamide) in gram doses reduces TC, LDL-C and TG, and increases HDL-C. The magnitude of individual lipid and lipoprotein responses may be influenced by the severity and type of underlying lipid abnormality. The increase in HDL-C is associated with an increase in apolipoprotein A-I (Apo A-I) and a shift in the distribution of HDL subfractions. These shifts include an increase in the HDL2:HDL3 ratio, and an elevation in lipoprotein A-I (Lp A-I, an HDL particle containing only Apo A-I). Niacin treatment also decreases serum levels of Apo B, the major protein component of the VLDL and LDL fractions, and of lipoprotein a (Lp(a)), a variant form of LDL independently associated with coronary risk. In addition, niacin has been shown to cause favourable transformations in LDL particle size subclass distribution, converting the pattern B phenotype (characterised by a predominance of triglyceride-rich, small dense LDL) to pattern A (characterised by a predominance of large buoyant LDL) or the intermediate AB phenotype. Pattern B LDL phenotype is one manifestation of what has been termed the Atherogenic Lipoprotein Profile (ALP), a Mendelian dominant inherited condition which also includes low levels of HDL-C, raised triglyceride, and insulin resistance.

Epidemiologic, clinical and experimental studies have established that high LDL cholesterol (LDL-C), low High Density Lipoprotein cholesterol (HDL-C) and high plasma triglycerides (TG) promote human atherosclerosis and are risk factors for developing cardiovascular disease. Some studies have also shown that the total cholesterol (TC):HDL-C ratio (TC:HDL-C) is the best predictor of coronary artery disease. In addition, increased levels of HDL-C are associated with decreased cardiovascular risk. Drug therapies that reduce levels of LDL-C or decrease TG while simultaneously increasing HDL-C have demonstrated reductions in rates of cardiovascular mortality and morbidity.

Pharmacokinetics

Absorption

Niacin is rapidly and extensively absorbed (at least 60 to 76% of dose) when administered orally. To maximize bioavailability, administration of NIASPAN (extended-release niacin) with a low-fat meal or snack is recommended.

Single-dose bioavailability studies have demonstrated that NIASPAN tablet strengths are not interchangeable.

Distribution

Studies using radiolabeled niacin in mice showed that niacin and its metabolites concentrate in the liver, kidney and adipose tissue.

Metabolism

The pharmacokinetic profile of niacin is complicated due to rapid and extensive first-pass metabolism, which is species and dose-rate specific. In humans, one pathway is through a simple conjugation step with glycine to form nicotinuric acid which is then excreted in the urine, although there may be a small amount of reversible metabolism back to niacin. The other pathway results in the formation of nicotine adenine dinucleotide (NAD). It is unclear whether nicotinamide is formed as a precursor to, or following the synthesis of NAD. Nicotinamide is further metabolized to at least N-methylnicotinamide (MNA) and nicotinamide- N-oxide. MNA is further metabolized to two other compounds, N-methyl-2-pyridone-5- carboxamide (2PY) and N-methyl-4-pyridone-5-carboxamide (4PY). The formation of 2PY appears to predominate over 4PY in humans. At the doses used to treat hyperlipidaemia, these metabolic pathways are saturable, which explains the nonlinear relationship between niacin dose and plasma concentrations following multiple-dose NIASPAN administration (Table 3).

Table 3 - Mean Steady-State Pharmacokinetic Parameters for Plasma Niacin
NIASPANNiacin
dose/daygiven asPeak Concentration
(μg /mL)
Time to Peak (hr)AUC (μg·hr/mL)
1000 mg2x500 mg0.650.6
1500 mg2x750 mg09-04-15401-09-15
2000 mg2x1000 mg05-15-15546.2

Nicotinamide does not have hypolipidaemic activity; the activity of the other metabolites is unknown.

Excretion

Niacin and its metabolites are rapidly eliminated in the urine. Following single and multiple doses, approximately 60 to 75% of the niacin dose administered as NIASPAN was recovered in urine as niacin and metabolites; up to 12% was recovered as unchanged niacin after multiple dosing. The ratio of metabolites recovered in the urine was dependent on the dose administered.

Special Populations and Conditions

Pediatrics

No studies in patients under 21 years of age have been conducted with NIASPAN.

Geriatrics

No data is available.

Sex

Steady-state plasma concentrations of niacin and metabolites after administration of NIASPAN are generally higher in women than in men. Recovery of niacin and metabolites in urine, however, is generally similar for men and women, indicating that absorption is similar for both sexes. Data from the clinical trials suggest that women have a greater hypolipidaemic response than men at equivalent doses of NIASPAN.

Hepatic Insufficiency

No studies have been performed. NIASPAN should be used with caution in patients with a past history of liver disease, who consume substantial quantities of alcohol. NIASPAN is contraindicated in patients with active liver disease or unexplained transaminase elevations (see CONTRAINDICATIONS, and WARNINGS AND PRECAUTIONS, Hepatic/Biliary/Pancreatic).

Renal Insufficiency

There are no data available on the use of NIASPAN in patients with impaired renal function (see WARNINGS AND PRECAUTIONS).

Storage and stability

Temperature:

Store at room temperature, (15 to 30EC).

Others:

Keep in a safe place out of the reach of children.

Dosage forms, composition and packaging

NIASPAN (extended-release niacin) is supplied as unscored, off-white capsule-shaped tablets for oral administration that contain no colour additives and is available in two tablet strengths containing 500 mg and 1000 mg of niacin in an extended-release formulation.

NIASPAN tablets also contain the inactive ingredients methylcellulose, povidone, and stearic acid. Tablets are debossed with the tablet strength (500 or 1000) on one side. Tablets are supplied in bottles of 30 as shown below.

500 mg tablets:bottles of 30
1000 mg tablets:bottles of 30