Actonel: Indications, Dosage, Precautions, Adverse Effects
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Actonel – Product Information

Manufacture: Actavis
Country: Canada
Condition: Osteoporosis, Paget's Disease, Prevention of Osteoporosis
Class: Bisphosphonates
Form: Tablets
Ingredients: Risedronate Sodium, Crospovidone, Ferric Oxide (5, 35 & 75 Mg), Hydroxypropyl Cellulose, Hypromellose, Indigo Carmine (150 Mg), Lactose Monohydrate (5, 30 & 35 Mg), Magnesium Stearate, Microcrystalline Cellulose, Polyethylene Glycol, Silicon Dioxide And Titanium Dioxide, Edetate Disodium, Ferric Oxide Yellow, Magnesium Stearate, Methacrylic Acid Copolymer Dispersion, Polysorbate 80, Silicified Microcrystalline Cellulose, Simethicone, Sodium Starch Glycolate, Stearic Acid, Talc And Triethyl Citrate

ACTONEL

Risedronate Sodium (as the hemi-pentahydrate) Tablets, USP

5 mg, 30 mg, 35 mg, 75 mg, and 150 mg

ACTONEL DR

Risedronate Sodium (as the hemi-pentahydrate) Delayed-Release Tablets

35 mg

Summary Product Information

Route of
Administration
Dosage Form/
Strength
Clinically Relevant
Nonmedicinal Ingredients
oral ACTONEL film-coated tablet 5 mg, 30 mg, 35 mg, 75 mg and 150 mg lactose monohydrate (5 mg, 30 mg and 35 mg)
oral ACTONEL DR enteric-coated, delayed-release tablet 35 mg Edetate disodium (EDTA)
For a complete listing see DOSAGE FORMS, COMPOSITION AND PACKAGING section.

Indications and Clinical Use

ACTONEL (risedronate sodium hemi-pentahydrate) is indicated for:

  • the treatment and prevention of osteoporosis in postmenopausal women
  • the treatment of osteoporosis in men, to improve bone mineral density
  • the treatment and prevention of glucocorticoid-induced osteoporosis in men and women
  • Paget's disease of bone

ACTONEL DR (risedronate sodium hemi-pentahydrate) is indicated for:

  • the treatment of osteoporosis in postmenopausal women

Postmenopausal Osteoporosis

In the treatment of osteoporosis in postmenopausal women at risk of fracture, ACTONEL and ACTONEL DR prevent vertebral and nonvertebral osteoporosis-related (fragility) fractures and increase bone mineral density (BMD) at all measured skeletal sites of clinical importance for osteoporotic fractures, including spine, hip, and wrist.

Osteoporosis may be confirmed by the presence or history of osteoporotic fracture, or by the finding of low bone mass (e.g., at least 2 standard deviation [SD] below the premenopausal mean).

For the prevention of osteoporosis in postmenopausal women who are at risk of developing osteoporosis, ACTONEL preserves or increases BMD at sites of clinical importance.

ACTONEL may be considered in postmenopausal women who are at risk of developing osteoporosis and for whom the desired clinical outcome is to maintain bone mass and to reduce the risk of fracture.

Factors such as family history of osteoporosis (particularly maternal history), age, previous fracture, smoking, moderately low BMD, high bone turnover, thin body frame, Caucasian or Asian race, and early menopause are associated with an increased risk of developing osteoporosis and fractures.

Important Limitations of Use

The optimal duration of use has not been determined. Patients should have the need for continued therapy re-evaluated on a periodic basis (see DOSAGE AND ADMINISTRATION).

Paget’s Disease of Bone

ACTONEL is indicated for patients with Paget's disease of bone (osteitis deformans) having alkaline phosphatase levels at least two times the upper limit of normal, or who are symptomatic, or who are at risk for future complications from their disease, to induce remission (normalization of serum alkaline phosphatase).

Geriatrics

In ACTONEL and ACTONEL DR osteoporosis studies, 26-46% of patients were between 65 and 75 years of age and 10-23% were over 75 years of age. No overall differences in efficacy or safety were observed between these patients and younger patients (< 65 years) in the above osteoporosis studies. (See CLINICAL TRIALS section).

Pediatrics

Safety and efficacy in children and growing adolescents have not been established.

Contraindications

  • Patients who are hypersensitive to this drug or to any ingredient in the formulation. For a complete listing, see DOSAGE FORMS, COMPOSITION AND PACKAGING.
  • Hypocalcemia (see WARNINGS AND PRECAUTIONS, General).

Warnings and Precautions

General

Hypocalcemia and other disturbances of bone and mineral metabolism should be effectively treated before starting ACTONEL (risedronate sodium) therapy.

Adequate intake of calcium and vitamin D is important in all patients, especially in patients with Paget's disease in whom bone turnover is significantly elevated (see DRUG INTERACTIONS). ACTONEL DR delayed release tablets are formulated to release in the small intestine to provide effective absorption of risedronate when taken as directed with breakfast. Other ACTONEL formulations should be taken on an empty stomach at least 30 minutes before first food of the day. For this reason, ACTONEL 35 mg should not be substituted for ACTONEL DR 35 mg. Detailed dosing instructions (see DOSAGE AND ADMINISTRATION) are provided to ensure correct dosing of each ACTONEL therapy.

Osteonecrosis of the Jaw

In post-marketing reporting, osteonecrosis of the jaw has been reported in patients treated with bisphosphonates. The majority of reports occurred following dental procedures such as tooth extractions and have involved cancer patients treated with intravenous bisphosphonates, but some occurred in patients receiving oral treatment for postmenopausal osteoporosis and other diagnoses. Many had signs of local infection, including osteomyelitis. Osteonecrosis has other well documented multiple risk factors. It is not possible to determine if these events are related to bisphosphonates, to concomitant drugs or other therapies, to the patient’s underlying disease or to other co-morbid risk factors (e.g., anemia, infection, pre-existing oral disease). A dental examination with appropriate preventative dentistry should be considered prior to treatment with bisphosphonates in patients with concomitant risk factors (e.g., cancer, immune suppression, head and neck radiotherapy or poor oral hygiene). While on treatment, these patients should avoid invasive dental procedures if possible. For patients requiring dental procedures, there are no data available to suggest whether discontinuation of bisphosphonate treatment prior to the procedure reduces the risk of osteonecrosis of the jaw. Clinical judgment, based on individual risk assessment, should guide the management of patients undergoing dental procedures.

Atypical Subtrochanteric and Diaphyseal Femoral Fractures

Atypical, low-energy, or low trauma fractures of the femoral shaft have been reported in bisphosphonate-treated patients. These fractures can occur anywhere in the femoral shaft from just below the lesser trochanter to above the supracondylar flare and are transverse or short oblique in orientation without evidence of comminution.

Atypical femur fractures most commonly occur with minimal or no impact trauma to the affected area. They may be bilateral and many patients report prodromal pain in the affected area, usually presenting as dull, aching thigh pain, weeks to months before a complete fracture occurs. Poor healing of these fractures was also reported.

Any patient with a history of bisphosphonate exposure who presents with thigh or groin pain should be suspected of having an atypical fracture and should be evaluated to rule out an incomplete femur fracture. Patients presenting with an atypical fracture should also be assessed for symptoms and signs of fracture in the contra-lateral limb. Interruption of bisphosphonate therapy should be considered, pending a risk/benefit assessment. Although causality has not been established, the role of bisphosphonates cannot be ruled out.

Musculoskeletal

In postmarketing experience, severe and occasionally incapacitating bone, joint, and/or muscle pain has been reported in patients taking bisphosphonates (see ADVERSE REACTIONS). The time to onset of symptoms varied from one day to several months after starting the drug. Most patients had relief of symptoms after stopping the medication. A subset of patients had recurrence of symptoms when rechallenged with the same drug or another bisphosphonate. Consider discontinuing use if severe symptoms develop.

Gastrointestinal

Bisphosphonates may cause upper gastrointestinal (GI) disorders such as dysphagia, esophagitis, esophageal ulcer, and gastric ulcer (see ADVERSE REACTIONS). Since some bisphosphonates have been associated with esophagitis and esophageal ulcerations, to facilitate delivery to the stomach and minimize the risk of these events, patients should take ACTONEL and ACTONEL DR while in an upright position (i.e., sitting or standing) and with sufficient plain water (≥ 120 mL). Patients should not lie down for at least 30 minutes after taking the drug. Health professionals should be particularly careful to emphasize the importance of the dosing instructions to patients with a history of esophageal disorders (e.g., inflammation, stricture, ulcer, or disorders of motility).

Ophthalmologic

Ocular disturbances including conjunctivitis, uveitis, episcleritis, iritis, and scleritis have been reported with Actonel therapy. Patients with ocular events other than uncomplicated conjunctivitis should be referred to an ophthalmologist for evaluation. If ocular inflammatory symptoms are observed, treatment may have to be discontinued.

Renal

Risedronate sodium is not recommended for use in patients with severe renal impairment (creatinine clearance < 30 mL/min).

Special Populations

Pediatrics

The safety and efficacy of risedronate sodium in children and growing adolescents have not been established.

Pregnant Women

Risedronate sodium is not intended for use during pregnancy. There are no studies of risedronate sodium in pregnant women.

Nursing Women

Risedronate sodium is not intended for use with nursing mothers. It is not known whether risedronate is excreted in human milk. Risedronate was detected in feeding pups exposed to lactating rats for a 24-hour period post-dosing, indicating a small degree of lacteal transfer. Since many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from bisphosphonates, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Adverse Reactions

Adverse Drug Reaction Overview

Bisphosphonates may cause upper gastrointestinal disorders such as dysphagia, esophagitis, esophageal ulcer and gastric ulcer. It is therefore important to follow the recommended dosing instructions (see DOSAGE AND ADMINISTRATION).

Musculoskeletal pain, rarely severe, has been reported as a common adverse event in patients who received ACTONEL and ACTONEL DR for all indications and dosage forms.

In ACTONEL and ACTONEL DR osteoporosis studies, the most commonly reported adverse reactions were abdominal pain, dyspepsia and nausea. In addition, diarrhea was the most commonly reported adverse reaction for the highest ACTONEL monthly dose.

In Paget’s disease studies with ACTONEL, the most commonly reported adverse reactions were diarrhea, nausea, abdominal pain and headache.

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 approximate rates of occurrence.

Treatment and Prevention of Postmenopausal Osteoporosis

ACTONEL 5 mg daily has been studied for up to 3 years in over 5000 women enrolled in Phase III clinical trials for treatment or prevention of postmenopausal osteoporosis. Most adverse events reported in these trials were either mild or moderate in severity, and did not lead to discontinuation from the study. The distribution of severe adverse events was similar across treatment groups. In addition, the overall incidence of adverse events (AEs) was found to be comparable amongst ACTONEL and placebo-treated patients.

Table 1 lists adverse events considered possibly or probably drug-related, reported in ≥ 1% of ACTONEL 5 mg daily-treated patients, in Phase III postmenopausal osteoporosis trials. Discontinuation of therapy due to serious clinical adverse events occurred in 5.5% of ACTONEL 5 mg daily-treated patients and 6.0% of patients treated with placebo.

Table 1 Drug-Related* Adverse Events Reported in ≥ 1% of ACTONEL 5 mg Daily-Treated Patients in Combined Phase III Postmenopausal Osteoporosis Trials
Adverse Event ACTONEL 5 mg
N = 1742
(%)
Placebo Control
N = 1744
(%)
Body as a Whole
Abdominal Pain 4.1 3.3
Headache 2.5 2.3
Asthenia 1.0 0.7
Digestive System
Dyspepsia 5.2 4.8
Nausea 4.8 5.0
Constipation 3.7 3.6
Diarrhea 2.9 2.5
Flatulence 2.1 1.8
Gastritis 1.1 0.9
Skin and Appendages
Rash 1.4 0.9
Pruritus 1.0 0.5
* Considered to be possibly or probably causally related by clinical study Investigators.

Weekly Dosing

In the 1-year, double-blind, multicentre study comparing ACTONEL 35 mg Once-a-Week to ACTONEL 5 mg daily for the treatment of osteoporosis in postmenopausal women, the overall safety and tolerability profiles of the 2 oral dosing regimens were similar.

The proportion of patients who experienced an upper gastrointestinal adverse event and the pattern of those events were found to be similar between the ACTONEL 35 mg Once-a-Week and ACTONEL 5 mg daily-treated groups. In addition to the previously described adverse reactions reported in ACTONEL osteoporosis clinical trials, arthralgia (ACTONEL 35 mg, 2.1%; ACTONEL 5 mg, 1.3%) was reported in ≥ 1% of patients and in more ACTONEL 35 mg weekly treated patients than in ACTONEL 5 mg daily treated patients.

In the 1-year, double-blind, multicentre study comparing ACTONEL 35 mg Once-a-Week to placebo for the prevention of osteoporosis in postmenopausal women, the overall safety and tolerability profiles of the two groups were comparable with the exception of arthralgia. Specifically, 1.5% of patients taking ACTONEL 35 mg Once-a-Week experienced arthralgia compared to 0.7% of placebo patients. The overall safety profile observed in this study showed no substantive difference from that observed in the ACTONEL 5 mg daily versus ACTONEL 35 mg Once-a-Week treatment study.

ACTONEL DR - In a 2-year, double-blind, multicentre study comparing ACTONEL DR 35 mg weekly taken following breakfast to ACTONEL 5 mg daily for the treatment of osteoporosis in postmenopausal women, gastrointestinal adverse events were reported in 38.8% of patients taking ACTONEL DR 35 mg, compared to 34.9% of patients taking ACTONEL 5 mg. Abdominal pain, vomiting, and upper abdominal pain were reported more frequently by patients taking ACTONEL DR (6.2%, 4.9%, 3.6%) compared to patients taking ACTONEL 5 mg (3.3%, 3.3%, 2.6%). Other events reported more frequently by patients taking ACTONEL DR included diarrhea, constipation, nasopharyngitis, upper respiratory tract infection, and pharyngitis.

Monthly Dosing

Two Consecutive Days per Month – In a 1-year, double-blind, multicentre study for the treatment of osteoporosis in postmenopausal women comparing ACTONEL 75 mg on two consecutive days per month to ACTONEL 5 mg daily, the overall safety profiles of the dosing regimens were similar. The proportion of patients who experienced an upper gastrointestinal adverse event and the pattern of those events were found to be similar between the ACTONEL 75 mg two consecutive days per month and the ACTONEL 5 mg daily treated groups. In addition to the previously described adverse reactions, arthralgia (ACTONEL 75 mg, 1.5%; ACTONEL 5 mg, 1.0%), vomiting (ACTONEL 75 mg, 1.1%; ACTONEL 5 mg, 1.0%) and gastritis erosive (ACTONEL 75 mg, 1.0%; ACTONEL 5 mg, 0.3%) was reported in ≥ 1% of patients and in more ACTONEL 75 mg treated patients than in ACTONEL 5 mg daily treated patients.

Symptoms consistent with acute phase reactions have been reported. Based on reporting of any 33 acute phase reaction-like symptoms (without regard to causality) within the first 5 days of first dose, the overall incidence of acute phase reaction was 7.6% of patients on ACTONEL 75 mg two consecutive days per month and 3.6% of patients on ACTONEL 5 mg daily. Fever or influenza-like illness (without regard to causality) occurring within the first 5 days of first dose were reported by 0.6% of patients in the ACTONEL 75 mg two consecutive days per month and 0.0% in the ACTONEL 5 mg daily groups.

Once-a-Month – In a 1-year, double-blind, multicentre study for the treatment of osteoporosis in postmenopausal women comparing ACTONEL 150 mg Once-a-Month to ACTONEL 5 mg daily, the overall safety profiles of the dosing regimens were similar. The proportion of patients who experienced an upper gastrointestinal adverse event and the pattern of those events were found to be similar between the ACTONEL 150 mg Once-a-Month and the ACTONEL 5 mg daily treated groups. In addition to the previously described adverse reactions diarrhea (ACTONEL 150 mg, 3.1%; ACTONEL 5 mg, 0.5%), vomiting (ACTONEL 150 mg, 1.5%; ACTONEL 5 mg, 0.6%), arthralgia (ACTONEL 150 mg, 1.5%; ACTONEL 5 mg, 0.9%) and myalgia (ACTONEL 150 mg, 1.1%; ACTONEL 5 mg, 0.3%) were reported in ≥1% of patients and in more ACTONEL 150 mg treated patients than in ACTONEL 5 mg daily treated patients.

Symptoms consistent with acute phase reactions have been reported. Based on reporting of any 33 acute phase reaction-like symptoms (without regard to causality) within the first 3 days of first dose and lasting less than 7 days, the overall incidence of acute phase reaction was 5.2 % of patients in the ACTONEL 150 mg once-a-month group and 1.1% in the ACTONEL 5 mg daily group. Fever or influenza-like illness (without regard to causality) occurring within the first 3 days of first dose and lasting less than 7 days was reported by 1.4% of patients in the ACTONEL 150 mg Once-a-Month group and 0.2% of patients in the ACTONEL 5 mg daily group.

Treatment of Osteoporosis in Men, to Improve Bone Mineral Density

In a 2-year, double-blind, multicentre study using ACTONEL 35 mg Once-a-Week (n=191) and placebo (n=93) in men with osteoporosis, the overall safety and tolerability profiles of the two treatment groups were similar.

The proportion of patients who experienced an upper gastrointestinal adverse event and the pattern of those events were higher in placebo (18%) than in ACTONEL 35 mg Once-a-Week treated patients (8%).

In addition to the previously described adverse events, the following adverse events were reported in ≥ 2% of patients and in more ACTONEL-treated patients than placebo-treated patients in the male osteoporosis study (events are included without attribution of causality): hypoaesthesia (ACTONEL 35 mg, 2%; placebo, 1%), nephrolithiasis (ACTONEL 35 mg, 3%; placebo, 0%), benign prostatic hyperplasia (ACTONEL 35 mg, 5%; placebo, 3%) and arrhythmia (ACTONEL 35 mg, 2%; placebo, 0%).

Glucocorticoid-Induced Osteoporosis

ACTONEL 5 mg daily has been studied in two Phase III glucocorticoid-induced osteoporosis trials enrolling more than 500 patients. The adverse event profile of this population was similar to that seen in postmenopausal osteoporosis trials.

The overall incidence of adverse events was found to be comparable between the ACTONEL 5 mg daily and placebo treatment groups, with the exception of back and joint pain. Back pain was reported in 8.8% of placebo-treated patients and 17.8% of ACTONEL-treated patients; joint pain occurred in 14.7% of placebo patients and 24.7% of ACTONEL patients. Most adverse experiences reported were either mild or moderate in severity, and did not lead to discontinuation from the study. Discontinuation of therapy due to serious clinical adverse events occurred in 2.9% of ACTONEL 5 mg daily-treated patients and 5.3% of patients treated with placebo. The occurrence of adverse events does not appear to be related to patient age, gender or race.

Table 2 lists adverse events considered possibly or probably drug-related, reported in ≥ 1% of ACTONEL 5 mg daily-treated patients, in Phase III glucocorticoid-induced osteoporosis studies.

Table 2 Drug-Related* Adverse Events Reported in ≥ 1% of ACTONEL 5 mg Daily-Treated Patients in the Phase III Glucocorticoid-Induced Osteoporosis Trials
Adverse Event ACTONEL 5 mg
N = 174
(%)
Placebo Control
N = 170
(%)
Body as a Whole
Abdominal Pain 4.0 4.7
Headache 1.1 1.2
Digestive System
Dyspepsia 5.7 2.9
Nausea 5.7 5.3
Constipation 2.9 3.5
Diarrhea 2.9 3.5
Dry Mouth 1.1 0.6
Duodenitis 1.1 0.0
Esophagitis 1.1 0.0
Flatulence 1.1 1.8
Gastrointestinal Disorder 1.1 0.0
Nervous System
Dizziness 1.1 1.2
Skin and Appendages
Rash 1.1 2.4
Skin Disorder 1.1 0.0
* Considered to be possibly or probably causally related by clinical study Investigators.

Endoscopic Findings

ACTONEL 5 mg daily clinical studies enrolled over 5700 patients for the treatment and prevention of postmenopausal and glucocorticoid-induced osteoporosis, many with pre-existing gastrointestinal disease and concomitant use of NSAIDs or ASA. Investigators were encouraged to perform endoscopies in any patients with moderate-to-severe gastrointestinal complaints while maintaining the blind. These endoscopies were ultimately performed on equal numbers of patients between the treated and placebo groups (75 ACTONEL; 75 placebo).

Across treatment groups, the percentage of patients with normal esophageal, gastric and duodenal mucosa on endoscopy was similar (21% ACTONEL; 20% placebo). Positive findings on endoscopy were also generally comparable across treatment groups. There were a higher number of reports of mild duodenitis in the ACTONEL group; however, there were more duodenal ulcers in the placebo group. Clinically important findings (perforations, ulcers or bleeding) among this symptomatic population were similar between groups (39% ACTONEL; 51% placebo).

At the 1-year time point in studies, comparing ACTONEL 35 mg Once-a-Week to ACTONEL 5 mg daily and ACTONEL DR 35 mg weekly to ACTONEL 5 mg daily in the treatment of postmenopausal osteoporosis, endoscopies performed during the studies revealed no dose dependent pattern in the number of patients with positive endoscopic findings or in the anatomical location of abnormalities detected. Endoscopies were conducted only on consenting patients experiencing moderate to severe gastrointestinal complaints.

In two, 1-year studies for the treatment of osteoporosis in postmenopausal women comparing ACTONEL 75 mg on two consecutive days per month and ACTONEL 150 mg Once-a-Month respectively to ACTONEL 5 mg daily, a similar percentage of patients for each of the intermittent regimens had at least one abnormal endoscopic finding when compared to the daily regimen (ACTONEL 75 mg, 3.2%; ACTONEL 5 mg, 3.1% and ACTONEL 150 mg, 3.4%; ACTONEL 5 mg, 4.2%).

Paget’s Disease of Bone

ACTONEL has been studied in over 390 patients with Paget's disease of bone. The adverse experiences reported have usually been mild or moderate and generally have not required discontinuation of treatment. The occurrence of adverse experiences does not appear to be related to patient age, gender or race.

In a Phase III clinical study, ACTONEL and Didronel (etidronate disodium tablets) showed similar adverse event profiles: 6.6% (4/61) of the patients treated with ACTONEL 30 mg daily for 2 months discontinued treatment due to adverse experiences, compared with 8.2% (5/61) of the patients treated with Didronel 400 mg daily for 6 months.

Table 3 lists adverse events considered possibly or probably drug-related, reported in ≥ 1% of ACTONEL 30 mg daily-treated patients, in the Phase III Paget’s trial.

Table 3 Drug-Related* Adverse Events Reported in ≥ 1% of ACTONEL 30 mg Daily-Treated Patients in the Phase III Paget’s Trial
Adverse Event ACTONEL
30 mg/day x 2 months
N = 61
(%)
Didronel
400 mg/day x 6 months
N = 61
(%)
Body as a Whole
Abdominal Pain 6.6 3.3
Headache 4.9 6.6
Infection 3.3 6.6
Flu Syndrome 1.6 0.0
Neck Rigidity 1.6 1.6
Neoplasm 1.6 0.0
Pain 1.6 8.2
Chest Pain 1.6 0.0
Digestive System
Diarrhea 13.1 9.8
Nausea 8.2 4.9
Constipation 3.3 1.6
Flatulence 3.3 4.9
Colitis 1.6 0.0
Metabolic and Nutritional
Peripheral Edema 1.6 0.0
Hypocalcemia 1.6 0.0
Weight Decreased 1.6 0.0
Musculoskeletal System
Arthralgia 9.8 8.2
Leg Cramps 1.6 0.0
Myasthenia 1.6 0.0
Bone Pain 1.6 0.0
Nervous System
Dizziness 1.6 0.0
Respiratory System
Apnea 1.6 0.0
Bronchitis 1.6 0.0
Sinusitis 1.6 0.0
Skin
Rash 1.6 0.0
Special Senses
Amblyopia 1.6 0.0
Corneal Lesion 1.6 0.0
Dry Eyes 1.6 0.0
Ear Pain 1.6 1.6
Tinnitus 1.6 0.0
Urogenital System
Nocturia 1.6 0.0
* Considered to be possibly or probably causally related by clinical study Investigators.

In the Phase III comparative study versus Didronel, patients with a history of upper GI disease or abnormalities were not excluded. Patients were also not excluded based on NSAID or ASA use. The proportion of ACTONEL 30 mg daily-treated patients with mild or moderate upper GI experiences was similar to that in the Didronel-treated group, with no severe upper GI experiences observed in either treatment group.

Less Common Clinical Trial Adverse Drug Reactions

The following adverse drug reactions were reported in ≤ 1% of patients who received ACTONEL for all indications:

  • Uncommon (0.1-1.0%): duodenitis, iritis
  • Rare (< 0.1%): abnormal liver function tests, glossitis

Abnormal Hematologic and Clinical Chemistry Findings

Asymptomatic mild decreases in serum calcium and phosphorus levels have been observed in some patients. Asymptomatic elevations in PTH levels were observed in some patients receiving Actonel DR (see ACTION AND CLINICAL PHARMACOLOGY, Pharmacodynamics).

Rare cases of leukemia have been reported following therapy with bisphosphonates. Any causal relationship to either the treatment or to the patients' underlying disease has not been established.

Post-Market Adverse Drug Reactions

Hypersensitivity and Skin Reactions

Reported rarely, angioedema, generalized rash and bullous skin reactions, some severe.

Musculoskeletal and Connective tissue

Reported very rarely, low-energy femoral shaft fractures (see WARNINGS AND PRECAUTIONS).

Osteonecrosis of the Jaw

Osteonecrosis of the jaw has been reported rarely (see WARNINGS AND PRECAUTIONS).

Ophthalmologic

Reported rarely, conjunctivitis, episcleritis, iritis, scleritis and uveitis (see WARNINGS AND PRECAUTIONS).

Drug Interactions

Overview

No specific drug-drug interaction studies were performed with risedronate sodium film-coated tablets. Animal studies have demonstrated that risedronate is highly concentrated in bone and is retained only minimally in soft tissue. No metabolites have been detected systemically or in bone. The binding of risedronate to plasma proteins in humans is low (24%), resulting in minimal potential for interference with the binding of other drugs. In an additional animal study, there was also no evidence of hepatic microsomal enzyme induction. In summary, risedronate sodium is not systemically metabolized, does not induce cytochrome P450 enzymes and has low protein binding.

Risedronate sodium is therefore not expected to interact with other drugs based on the effects of protein binding displacement, enzyme induction or metabolism of other drugs.

In vitro studies suggest that the amount of EDTA contained in the ACTONEL DR formulation (approximately 1.5 mM ) will not significantly affect aqueous solubility of antivirals (nelfinavir, lamivudine, emtricitabin) and drugs with a narrow therapeutic index (digoxin, lithium carbonate, potassium chloride). Thus, co-administration with ACTONEL DR is not likely to alter their absorption.

Drug-Drug Interactions

Patients in the clinical trials were exposed to a wide variety of commonly used concomitant medications (including NSAIDs, H2-blockers, proton pump inhibitors, antacids, calcium channel blockers, beta-blockers, thiazides, glucocorticoids, anticoagulants, anticonvulsants, cardiac glycosides). While there was no apparent evidence of clinically relevant interactions in the clinical trials, such interactions cannot be ruled out on the basis on these data.

The drugs listed in Table 4 are based on either drug interaction case reports or predicted interactions due to the expected magnitude and seriousness of the interaction (i.e., those identified as contraindicated).

Table 4 Established or Predicted Drug-Drug Interactions with ACTONEL/ACTONEL DR
Reference Effect Clinical Comment
Antacids and calcium supplements which contain polyvalent cations (e.g., calcium, magnesium, aluminum and iron) CT/T Interference with the absorption of ACTONEL and ACTONEL DR. Co-administration of ACTONEL DR with calcium supplement after breakfast reduced bioavailability of ACTONEL DR by approximately 38%. Such medications should be administered at a different time of the day from ACTONEL or ACTONEL DR (see DOSAGE AND ADMINISTRATION).
Hormone replacement therapy (HRT) CT No clinically significant effect for ACTONEL If considered appropriate, ACTONEL may be used concomitantly with HRT (see CLINICAL TRIALS, Study 11). No data are available on the concomitant use of ACTONEL DR and HRT
H2-blockers and proton pump inhibitors (PPIs) CT Among H2-blockers and PPIs users, the incidence of upper gastrointestinal adverse events was similar between the ACTONEL-treated patients and placebo-treated patients. Of over 5700 patients enrolled in the ACTONEL 5 mg daily Phase III osteoporosis studies, 21% used H2-blockers and/or PPIs.
Among H2-blockers and PPIs users, the incidence of upper gastrointestinal adverse experiences was found to be similar between the weekly- and daily-treated groups. In the 1-year study comparing ACTONEL Once-a-Week and daily dosing regimens in postmenopausal women with osteoporosis, at least 9% of patients in the ACTONEL 35 mg Once-a-Week and 5 mg daily groups used H2-blockers and/or PPIs.
Concomitant administration of PPIs and Actonel DR has been shown to affect the bioavailability of ACTONEL DR (see ACTION AND CLINICAL PHARMACOLOGY, Absorption).
The effects of concomitant administration of H2-blockers on bioavailability of ACTONEL DR have not been evaluated.
In the 2-year study comparing ACTONEL DR and daily dosing regimens in postmenopausal women with osteoporosis, at least 8% and 14% of patients in the ACTONEL DR and 5 mg daily groups used H2-blockers and/or PPIs respectively.
Concomitant administration of ACTONEL DR and H2 blockers or PPIs is not recommended.
CT: Clinical Trial; T: Theoretical

Of over 5700 patients enrolled in the ACTONEL 5 mg daily Phase III osteoporosis studies, ASA use was reported by 31% of patients and NSAID use by 48%. Among these ASA or NSAID users, the incidence of upper gastrointestinal adverse events was similar between the ACTONEL-treated patients and placebo-treated patients.

In the 1-year study comparing ACTONEL 35 mg Once-a-Week to ACTONEL 5 mg daily, ASA use was reported by 56% and NSAID use by 41%. The incidence of upper gastrointestinal adverse events was similar between the ACTONEL weekly- and daily-treated groups.

In the Phase 3 study comparing ACTONEL DR 35 mg weekly immediately following breakfast and ACTONEL 5 mg daily, 22% of NSAID/ASA users in both groups developed upper gastrointestinal adverse reactions. Among non-users, 16% of patients taking ACTONEL DR 35 mg weekly immediately following breakfast developed upper gastrointestinal adverse reactions, compared to 13% taking ACTONEL 5 mg daily.

In two, 1-year studies comparing ACTONEL 75 mg two consecutive days per month or ACTONEL 150 mg once-a-month to ACTONEL 5 mg daily in postmenopausal women, 55% (75 mg) and 46% (150 mg) of patients reported the use of ASA and/or NSAIDs. Among these ASA or NSAID users, the incidence of upper gastrointestinal adverse events was similar in the ACTONEL monthly-treated groups when compared to the daily-treated groups respectively.

Drug-Food Interactions

Clinical benefits may be compromised by failure to take ACTONEL on an empty stomach.

ACTONEL DR should be taken with food. When compared with ACTONEL 5 mg, treatment with ACTONEL DR resulted in a higher incidence of upper abdominal pain when administered before breakfast under fasting conditions. For dosing information see DOSAGE AND ADMINISTRATION.

Drug-Herb Interactions

Interactions with herbs have not been studied.

Drug-Laboratory Interactions

Bisphosphonates are known to interfere with the use of bone-imaging agents. Specific studies with ACTONEL and ACTONEL DR have not been performed.

Dosage and Administration

Dosing Considerations

Patients should receive supplemental calcium and vitamin D if dietary intake is inadequate (see WARNINGS AND PRECAUTIONS, General).

ACTONEL (risedronate sodium) film-coated tablets

  • ACTONEL should be taken on an empty stomach at least 30 minutes before consuming the first food, drink (other than plain water) and/or any other medication of the day. Food, medication or drink other than plain water can interfere with the absorption of ACTONEL. (See Recommended Dose and Dosage Adjustment and Drug Interactions)
  • Each ACTONEL tablet should be swallowed whole while the patient is in an upright position and with sufficient plain water (≥ 120 mL) to facilitate delivery to the stomach.
  • Patients taking ACTONEL should not lie down for at least 30 minutes after taking the medication (see WARNINGS AND PRECAUTIONS, General).
  • ACTONEL tablets should not be chewed, cut, or crushed (see WARNINGS AND PRECAUTIONS, General).
  • Medications containing polyvalent cations (e.g. calcium, magnesium, aluminum, and iron) can interfere with the absorption of ACTONEL. These medications should be administered at a different time of the day than ACTONEL.
  • The optimal duration of bisphosphonate treatment for osteoporosis has not been established. The need for continued treatment should be re-evaluated periodically based on the benefits and potential risks of ACTONEL on an individual patient basis.

ACTONEL DR (risedronate sodium) delayed-release tablets

  • ACTONEL DR should be taken in the morning, with breakfast, (this may include high fat foods, coffee, tea, milk, orange juice, etc. (See Recommended Dose and Dosage Adjustment section). A higher incidence of upper abdominal pain was seen when ACTONEL DR was taken in a fasted state before breakfast (see WARNINGS AND PRECAUTIONS – Drug-food interactions).
  • Each ACTONEL DR tablet should be swallowed whole while the patient is in an upright position and with sufficient plain water (≥ 120 mL) to facilitate delivery to the stomach.
  • Patients taking ACTONEL DR should not lie down for at least 30 minutes after taking the medication (see WARNINGS AND PRECAUTIONS, General).
  • ACTONEL DR tablets should not be chewed, cut, or crushed. Care should be taken not to break the outer coating which is designed to remain intact until the tablet reaches the small intestine where the tablet coating dissolves and releases the active ingredient (see WARNINGS AND PRECAUTIONS, General).
  • Calcium supplements and antacids can interfere with the absorption of ACTONEL DR. These medications should be administered at a different time of the day than ACTONEL DR.
  • The optimal duration of bisphosphonate treatment for osteoporosis has not been established. The need for continued treatment should be re-evaluated periodically based on the benefits and potential risks of ACTONEL DR on an individual patient basis.

Recommended Dose and Dosage Adjustment

For all indications and doses

The patient should be informed to pay particular attention to the dosing instructions as clinical benefits may be compromised by failure to take the drug according to instructions.

Treatment of Postmenopausal Osteoporosis

The recommended regimens are daily (5 mg), weekly (35 mg Once-a-Week film-coated and delayed-release tablets), monthly duet (75 mg on two consecutive days per month, on the same calendar days each month) or monthly (1 tablet of 150 mg once-a-month on the same calendar day each month), taken orally.

Prevention of Postmenopausal Osteoporosis

The recommended regimens are daily (5 mg) or weekly (35 mg Once-a-Week film-coated tablets), taken orally.

Treatment of Osteoporosis in Men, to Improve Bone Mineral Density

The recommended regimen is 35 mg Once-a-Week film-coated tablets, taken orally.

Treatment and Prevention of Glucocorticoid-Induced Osteoporosis

The recommended regimen is 5 mg daily, taken orally.

Treatment of Paget’s Disease of Bone

The recommended regimen is 30 mg daily for 2 months, taken orally. Re-treatment may be considered (following post-treatment observation of at least 2 months) if relapse has occurred, or if treatment fails to normalize serum alkaline phosphatase. For re-treatment, the dose and duration of therapy are the same as for initial treatment. There are no data available on more than one course of re-treatment.

Renal Impairment

No dosage adjustment is necessary in patients with a creatinine clearance ≥ 30 mL/min or in the elderly. Not recommended for use in patients with severe renal impairment (creatinine clearance < 30 mL/min).

Geriatrics

No dosage adjustment is necessary in elderly patients (see INDICATIONS AND CLINICAL USE, Geriatrics).

Missed Dose

Daily

Patients should be instructed that if they miss a dose of ACTONEL 5 mg or 30 mg, they should take 1 tablet of ACTONEL as they normally would for their next dose. Patients should not double their next dose or take 2 tablets on the same day.

Weekly

Patients should be instructed that if they miss a dose of ACTONEL or ACTONEL DR 35 mg Once-a-Week on their regularly scheduled day, they should take 1 tablet on the day they first remember missing their dose. Patients should then return to taking 1 tablet once a week as originally scheduled on their chosen day. Patients should not take 2 tablets on the same day.

Monthly Duet

If one or both tablets of ACTONEL 75 mg monthly duet are missed, and the next month’s scheduled doses are more than 7 days away, the patient should be instructed as follows:

  • If both tablets are missed, take 1 ACTONEL 75 mg tablet in the morning after the day it is remembered and then the other tablet on the next consecutive morning.
  • If only 1 ACTONEL 75 mg tablet is missed, take the missed tablet in the morning after the day it is remembered.

Patients should then return to taking their ACTONEL 75 mg monthly duet on two consecutive days each month as originally scheduled. Patients should not take more than two 75 mg tablets within 7 days. If one or both tablets of ACTONEL 75 mg are missed, and the next month's scheduled doses are within 7 days, patients should wait until their next month’s scheduled doses and then continue taking ACTONEL 75 mg monthly duet on two consecutive days each month as originally scheduled.

Once-a-Month

Patients should be instructed that if they miss a 150 mg dose of ACTONEL (1 tablet of 150 mg), and the next month’s scheduled dose is more than 7 days away, they should take the missed tablet in the morning after the day it is remembered. Patients should then return to taking their ACTONEL 150 mg as originally scheduled.

If a dose of ACTONEL 150 mg is missed, and the next month’s scheduled dose is within 7 days, patients should be instructed to wait until their next month’s scheduled dose and then continue taking ACTONEL 150 mg. Patients should not take more than 150 mg of ACTONEL within 7 days.

Overdosage

Decreases in serum calcium following substantial overdose may be expected in some patients. Signs and symptoms of hypocalcemia may also occur in some of these patients.

Milk or antacids containing calcium, magnesium, and aluminum may be given to bind ACTONEL (film-coated tablets) and reduce absorption of the drug; the impact of this intervention for ACTONEL DR (delayed-release tablets) has not been evaluated. The ACTONEL DR formulation is less sensitive to the binding effects of divalent cations. In cases of substantial overdose, gastric lavage may be considered to remove unabsorbed drug if performed within 30 minutes of ingestion. Standard procedures that are effective for treating hypocalcemia, including the administration of calcium intravenously, would be expected to restore physiologic amounts of ionized calcium and to relieve signs and symptoms of hypocalcemia.

For management of a suspected drug overdose, contact your regional Poison Control Centre.

Action and Clinical Pharmacology

Mechanism of Action

Risedronate sodium, a pyridinyl-bisphosphonate in the form of hemi-pentahydrate with small amounts of monohydrate, inhibits osteoclast bone resorption and modulates bone metabolism. Risedronate has a high affinity for hydroxyapatite crystals in bone and is a potent antiresorptive agent. At the cellular level, risedronate inhibits osteoclasts. The osteoclasts adhere normally to the bone surface, but show evidence of reduced active resorption (e.g., lack of ruffled border). Histomorphometry in rats, dogs, minipigs and humans showed that risedronate treatment reduces bone turnover (i.e., activation frequency, the rate at which bone remodelling sites are activated) and bone resorption at remodelling sites.

Pharmacodynamics

Treatment and Prevention of Osteoporosis in Postmenopausal Women

Osteoporosis is a degenerative and debilitating bone disease characterized by decreased bone mass and increased fracture risk at the spine, hip, and wrist. The diagnosis can be confirmed by the finding of low bone mass, evidence of fracture on x-ray, a history of osteoporotic fracture, or height loss or kyphosis indicative of vertebral fracture. Osteoporosis occurs in both men and women but is more common among women following menopause.

In healthy humans, bone formation and resorption are closely linked; old bone is resorbed and replaced by newly-formed bone. In postmenopausal osteoporosis, bone resorption exceeds bone formation, leading to bone loss and increased risk of bone fracture. After menopause, the risk of fractures of the spine and hip increases dramatically; approximately 40% of 50-year-old women will experience an osteoporosis-related fracture of the spine, hip, or wrist during their remaining lifetimes. After experiencing one osteoporosis-related fracture, the risk of future fracture increases 5-fold compared to the risk among a non-fractured population. One in five men older than 50 years will have an osteoporotic fracture, most commonly at the spine, hip and wrist.

Risedronate sodium treatment decreases the elevated rate of bone turnover and corrects the imbalance of bone resorption relative to bone formation that is typically seen in postmenopausal osteoporosis. In clinical trials, administration of ACTONEL to postmenopausal women resulted in dose-dependent decreases in biochemical markers of bone turnover, including urinary markers of bone resorption and serum markers of bone formation, at doses as low as 2.5 mg daily. At the 5 mg daily dose, decreases in resorption markers were evident within 14 days of treatment. Changes in bone formation markers were observed later than changes in resorption markers, as expected, due to the coupled nature of bone formation and bone resorption; decreases in bone formation of about 20% were evident within 3 months of treatment. Bone turnover markers (BTMs) reached a nadir of about 40% below baseline values by the sixth month of treatment and remained stable with continued treatment for up to 3 years.

These data demonstrate that ACTONEL 5 mg administered daily to postmenopausal women produces a rapid reduction in bone resorption without over-suppression of bone formation. Bone turnover is decreased as early as 2 weeks and maximally within about 6 months of treatment, with achievement of a new steady-state which more nearly approximates the rate of bone turnover seen in premenopausal women.

In weekly and monthly ACTONEL postmenopausal osteoporosis dosing studies, consistent decreases in bone resorption (50-60%) and bone formation (30-40%) markers were observed at Month 12. Similarly, in a 2-year study for the treatment of osteoporosis in postmenopausal women comparing ACTONEL DR 35 mg weekly to baseline, consistent decreases in bone resorption (47-50%, 49-54%) and bone formation (33-34%, 35-37%) markers were observed at Month 12 and Month 24, respectively.

As a result of the inhibition of bone resorption, asymptomatic and usually transient decreases from baseline in serum calcium (about 2%) and serum phosphate levels (about 5%) and compensatory increases in serum parathyroid hormone (PTH) levels were observed within 6 months in ACTONEL 5 mg daily-treated patients in postmenopausal osteoporosis trials. No further decreases in serum calcium or phosphate, or increases in PTH were observed in postmenopausal women treated for up to 3 years.

In two 1-year studies for the treatment of osteoporosis in postmenopausal women comparing ACTONEL 35 mg Once-a-Week and ACTONEL 150 mg Once-a-Month respectively to ACTONEL 5 mg daily, similar mean changes from baseline in serum calcium, phosphate and PTH were found for each of the intermittent regimens when compared to the daily dosage regimen. In the 1-year study comparing ACTONEL 75 mg on two consecutive days per month to ACTONEL 5 mg daily, the mean percent changes from baseline were for serum calcium (0.8% and 0.2%), phosphate (-1.1% and -1.9%) and PTH (-11.7% and -3.0%), respectively.

In a 2-year study for the treatment of osteoporosis in postmenopausal women comparing ACTONEL DR 35 mg weekly to ACTONEL 5 mg daily, similar mean percent changes from baseline to 2 years were found between the 2 oral dosing regimens in serum calcium and phosphate. The effect of Actonel DR 35 mg weekly and Actonel 5 mg daily on PTH was evaluated in postmenopausal women with osteoporosis. At 2 years, in subjects with normal levels at baseline, PTH levels greater than 65 ng/L (upper limit of normal) were noted in 12% of subjects receiving Actonel DR 35 mg weekly immediately following breakfast and 6% of subjects receiving Actonel 5mg daily. In subjects with normal levels at baseline, PTH levels greater than 97 ng/L (1.5 times the upper limit of normal) at 2 years were seen in 3% of subjects receiving Actonel DR 35 mg weekly immediately following breakfast and 0 subjects receiving Actonel 5 mg daily. There were no clinically significant differences between treatment groups for levels of calcium, phosphorus and magnesium.”

Consistent with the effects of ACTONEL on biochemical markers of bone turnover, daily oral doses as low as 2.5 mg produced dose dependent, significant increases in lumbar spine bone mineral density (BMD) (ACTONEL 2.5 mg, 3% to 3.7%; ACTONEL 5 mg, 4% to 4.5%) after 12 months of treatment in large-scale postmenopausal osteoporosis trials. A dose-dependent response to treatment was also observed in the BMD of the femoral neck over the same time (ACTONEL 2.5 mg, 0.7% to 0.9%; ACTONEL 5 mg, 1.5% to 2%). In three 1-year weekly and monthly dosing studies for the treatment of osteoporosis in postmenopausal women, comparing ACTONEL 35 mg Once-a-Week, ACTONEL 75 mg on two consecutive days per month and ACTONEL 150 mg Once-a-Month respectively to ACTONEL 5 mg daily, similar mean changes from baseline in BMD of the lumbar spine, total proximal femur, femoral neck and femoral trochanter were found for each of the intermittent regimens when compared to the daily regimen. In the two year study of ACTONEL DR 35 mg weekly, it was shown that at 1 year and 2 years, ACTONEL DR 35 mg weekly was non-inferior to the ACTONEL 5 mg daily regimen for the primary efficacy variable of percent change from baseline of lumbar spine BMD. The two treatment groups were also similar with regard to percent change from baseline BMD at the total proximal femur, greater trochanter and femoral neck. Non-inferiority was observed with ACTONEL DR relative to ACTONEL 5 mg. At 2 years, the mean percent change from baseline in lumbar spine BMD was 4.1% for ACTONEL 5mg and 5.2% for the ACTONEL DR 35 mg (upper limit CI = -0.355%). see CLINICAL TRIALS, Treatment of Osteoporosis in Postmenopausal Women).

The ACTONEL DR tablet has an enteric coating, which delays the release of risedronate until the small intestine. The other formulations of ACTONEL are film coated.

Treatment of Osteoporosis in Men, to Improve Bone Mineral Density

In a 2-year clinical trial in the treatment of osteoporosis in men, ACTONEL 35 mg Once-a-Week decreased urinary collagen cross-linked N-telopeptide (NTX) (a marker of bone resorption), and serum bone specific alkaline phosphatase (BAP) (a marker of bone formation) by approximately 40% and 30%, below baseline values, respectively, within 12 months. The BTMs all had statistically significant decreases in bone turnover from baseline compared to placebo at all time points. The decreases in bone turnover were observed within 3 months after initiation of therapy and maintained throughout the 2-year study.

Glucocorticoid-Induced Osteoporosis

Chronic exposure to glucocorticoids (≥ 7.5 mg/day prednisone or its equivalent) induces rapid bone loss by decreasing bone formation and increasing bone resorption. The bone loss occurs most rapidly during the first 6 months of therapy with persistent but slowing bone loss for as long as glucocorticoid therapy continues.

Glucocorticoid-induced osteoporosis is characterized by low bone mass that leads to an increased risk of fracture (especially vertebral, hip and rib). It occurs in both men and women, and approximately 50% of patients on chronic glucocorticoid treatment will experience fractures. The relative risk of a hip fracture in patients on > 7.5 mg/day prednisone is more than doubled (RR = 2.27); the relative risk of vertebral fracture is increased five-fold (RR = 5.18).

ACTONEL treatment decreases bone resorption without directly inhibiting bone formation. In 1-year clinical trials in the treatment and prevention of glucocorticoid-induced osteoporosis, ACTONEL 5 mg daily produced rapid and statistically significant reductions in biochemical markers of bone turnover, similar to those seen in postmenopausal osteoporosis. Urinary collagen cross-linked N-telopeptide (a marker of bone resorption) and serum bone specific alkaline phosphatase (a marker of bone formation) were decreased by 50% to 55% and 25% to 30%, respectively, within 3 to 6 months after initiation of therapy. The reduction was evident within 14 days and BTMs remained decreased throughout the duration of ACTONEL treatment.

Consistent with the changes in biochemical markers of bone turnover, ACTONEL 5 mg daily provides a beneficial effect on bone mineral density and reduces the risk of vertebral fractures by approximately 70% when compared to placebo (see CLINICAL TRIALS, Glucocorticoid- Induced Osteoporosis).

Paget's Disease of Bone

Paget’s disease of bone is a chronic focal skeletal disorder characterized by greatly increased and disordered bone remodelling. Excessive osteoclastic bone resorption is followed by osteoblastic new bone formation, leading to the replacement of the normal bone architecture by disorganized, enlarged and weakened bone structure.

Clinical manifestations of Paget’s disease range from no symptoms to severe morbidity due to bone pain, bone deformity, pathological fractures, and neurological and other complications. Serum alkaline phosphatase, the most frequently used biochemical marker of disease activity, provides an objective measure of disease severity and response to therapy.

ACTONEL is a bisphosphonate that acts primarily to inhibit bone resorption. This effect is related to its inhibitory effect on osteoclasts. In the Phase III clinical trial, ACTONEL 30 mg daily for 2 months produced significant (p < 0.001) reductions of 81% to 88% in serum alkaline phosphatase excess, as well as significant reductions in bone-specific serum alkaline phosphatase (Ostase, 67% to 70%) and urinary deoxypyridinoline/creatinine (47% to 51%). Reductions were evident as early as 1 month after the start of treatment, and progressively increased in magnitude (following completion of the 2 month treatment) when measured at monthly intervals over a 6 month period. Clinically meaningful reductions in serum alkaline phosphatase were observed starting at 1 month with levels maintained through 12 months.

Asymptomatic and mild decreases in serum calcium and phosphorus levels have been observed in some patients. These decreases in calcium are associated with increases in serum intact PTH and 1,25-dihydroxy vitamin D, resulting in an increase in tubular reabsorption of calcium. Markers of bone resorption (such as urinary deoxypyridinoline/creatinine or hydroxyproline/creatinine) usually decrease before markers of bone formation (such as serum alkaline phosphatase). This difference is indicative of the primary antiresorptive effect of ACTONEL.

Bone turnover marker levels continue to decrease when ACTONEL treatment is stopped. Therefore, to assess the full effect of response, patients should be followed for at least 2 months following the 2 month treatment period.

Pharmacokinetics

Table 5 Summary of Pharmacokinetic Parameters of Risedronate
Cmax
(ng/mL)
tmax
(h)
t1/2,z
(h)
AUC0 - ∞
(ng.h/mL)
Clearance
(L/h/kg)
Vz
(L/kg)
5 mg tablet; single dose 85 0.93a 206.1 3.45 19.94 5542
30 mg tablet; single dose 4.2 0.87a 226.1 17.1 23.60 7542
35 mg tablet; multiple doseb, steady state 10.6 0.49 nd 53.3 12.9 nd
35 mg DR tablet; single dose 14.1 3.0d nd 34.2e nd nd
75 mg tablet, multiple dosec, steady state 19.3d 0.66a 299.7d 180.7d 14.8a nd
150 mg tablet, single dose 74.8d 0.66d 349.6d 332.4d 6.94d 3118d
a: arithmetic mean; b: administered weekly; c: administered on two consecutive days per month (150 mg total monthly dose); d: geometric mean; t1/2 , z: is the half-life of the terminal exponential phase; VZ: is the terminal volume of distribution uncorrected for bioavailability; nd: not determined; e AUCtlast.

Absorption

Absorption after an oral dose is relatively rapid (tmax ~ 1 hour) for the film-coated tablet and occurs throughout the upper gastrointestinal tract. Absorption is independent of dose up to 75 mg two consecutive days per month; systemic exposure increases disproportionally at 150 mg (about 2 fold greater than expected based on dose). Steady-state conditions in the serum are observed within 57 days of daily dosing. The mean oral bioavailability of the 30 mg film-coated tablet is 0.63% and is bioequivalent to a solution. Extent of absorption when administered 30 minutes before breakfast is reduced by 55% compared to dosing in the fasting state (i.e., no food or drink for 10 hours prior to or 4 hours after dosing). Dosing 1 hour prior to breakfast reduces extent of absorption by 30% compared to dosing in the fasting state. Dosing either 30 minutes prior to breakfast or 2 hours after a meal results in a similar extent of absorption.

ACTONEL DR (risedronate sodium) 35 mg delayed-release tablet achieved a peak serum concentration at approximately 3 hours. Urinary excretion data showed that the fraction of the dose absorbed from ACTONEL DR is independent of the dose over the range studied (single dose, from 20 mg to 100 mg).

In a crossover pharmacokinetic study that evaluated food effect, the bioavailability of ACTONEL DR 35 mg delayed-release tablets decreased by ~30% when administered immediately after a high-fat breakfast compared to administration 4 hours before a meal. The bioavailability of the 35 mg Actonel DR tablet administered after a high fat breakfast was ~2 to 4-fold greater than the 35 mg risedronate film-coated tablet administered 30 minutes prior to a high-fat breakfast. Across different studies, the bioavailability of ACTONEL DR was not affected by breakfast meals with varying amount of fat and calories.

In a separate study, ACTONEL DR administered after dinner exhibited approximately 87% increase in exposure compared to administration following a breakfast. The safety and efficacy of dosing ACTONEL DR after dinner has not been evaluated (see DOSAGE AND ADMINISTRATION).

A post-approval cross-over pharmacokinetic study evaluated the impact of co-administered esomeprazole on the bioavailability of ACTONEL DR. Esomeprazole was administered 1 hour prior to breakfast for 6 days prior to one dose of ACTONEL DR administered after breakfast on day 6. The resulting median tmax values were shorter (3.5 vs 5.0 hours), and the Cmax and AUC values of ACTONEL DR increased 60% and 22%, respectively. A 47% increase in the amount of risedronate excreted was also observed.

Distribution

The mean steady-state volume of distribution is 6.3 L/kg in humans. Human plasma protein binding of drug is about 24%. Preclinical studies in rats and dogs dosed intravenously with single doses of [14C] risedronate indicate that approximately 60% of the dose is distributed to bone. The remainder of the dose is excreted in the urine. After multiple oral dosing in rats, the uptake of risedronate in soft tissues was found to be minimal (in the range of 0.001% to 0.01%), with drug levels quickly decreasing after the final dose.

Metabolism

There is no evidence that risedronate is systemically metabolized.

Excretion

Approximately half of the absorbed dose is excreted in urine within 24 hours, and 85% of an intravenous dose is recovered in the urine over 28 days. The mean renal clearance is 105 mL/min (CV = 34%) and mean total clearance is 122 mL/min (CV = 19%), with the difference primarily reflecting non-renal clearance or clearance due to adsorption to bone. The renal clearance is not concentration dependent, and there is a linear relationship between renal clearance and creatinine clearance. Unabsorbed drug is eliminated unchanged in feces. Once risedronate is absorbed, the serum concentration-time profile is multi-phasic with an initial half-life of about 1.5 hours and a terminal exponential half-life of 480 hours. Although the elimination rate of bisphosphonates from human bone is unknown, the 480 hour half-life is hypothesized to represent the dissociation of risedronate from the surface of bone.

Special Populations and Conditions

Pediatrics

Risedronate pharmacokinetics have not been studied in patients < 18 years of age.

Geriatrics

Bioavailability and disposition are similar in elderly (> 65 years of age) and younger subjects. No dosage adjustment is necessary.

Gender

Bioavailability and disposition following oral administration are similar in men and women.

Race

Pharmacokinetic differences due to race have not been studied.

Hepatic Insufficiency

No studies have been performed to assess risedronate's safety or efficacy in patients with hepatic impairment. Risedronate is not metabolized in rat, dog, and human liver preparations. Insignificant amounts (< 0.1% of intravenous dose) of drug are excreted in the bile in rats. Therefore, dosage adjustment is unlikely to be needed in patients with hepatic impairment.

Renal Insufficiency

Risedronate is excreted intact primarily via the kidney. Patients with mild-to-moderate renal impairment (creatinine clearance > 30 mL/min) do not require a dosage adjustment. Exposure to risedronate was estimated to increase by 44% in patients with creatinine clearance of 20 mL/min. ACTONEL and ACTONEL DR are not recommended for use in patients with severe renal impairment (creatinine clearance < 30 mL/min) because of a lack of clinical experience.

Genetic Polymorphism

No data are available.

Storage and Stability

Store at controlled room temperature 20°C - 25°C.

Dosage Forms, Composition and Packaging

ACTONEL

Medicinal Ingredients

Each risedronate sodium tablet for oral administration contains the equivalent of 5, 30, 35, 75 or 150 mg of anhydrous risedronate sodium in the form of the hemi-pentahydrate with small amounts of monohydrate.

Nonmedicinal Ingredients (Film-coated Tablets)

Crospovidone, ferric oxide red (35 and 75 mg), ferric oxide yellow (5 and 35 mg), hydroxypropyl cellulose, hypromellose, indigo carmine (150 mg), lactose monohydrate (5, 30 and 35 mg), magnesium stearate, microcrystalline cellulose, polyethylene glycol, silicon dioxide and titanium dioxide.

Dosage Strength Description Packaging
5 mg film-coated, oval-shaped, yellow tablets with “RSN” engraved on one face and “5 mg” engraved on the other carton of 28 blister packaged tablets
30 mg film-coated, oval-shaped, yellow tablets with “RSN” engraved on one face and “30 mg” engraved on the other bottle of 30 tablets
35 mg film-coated, oval-shaped, yellow tablets with “RSN” engraved on one face and “35 mg” engraved on the other carton of 4 blister packaged tablets
75 mg film-coated, oval-shaped, yellow tablets with “RSN” engraved on one face and “75 mg” engraved on the other carton of 2 blister packaged tablets
150 mg film-coated, oval-shaped, yellow tablets with “RSN” engraved on one face and “150 mg” engraved on the other carton of 1 blister packaged tablet

ACTONEL DR

Medicinal Ingredients

Each risedronate sodium tablet for oral administration contains the equivalent 35 mg of anhydrous risedronate sodium in the form of the hemi-pentahydrate with small amounts of monohydrate.

Nonmedicinal Ingredients (Delayed-release tablets)

Edetate disodium, ferric oxide yellow, magnesium stearate, methacrylic acid copolymer dispersion, silicified microcrystalline cellulose, polysorbate 80, simethicone, sodium starch glycolate, stearic acid, talc, and triethyl citrate.

Dosage Strength Description Packaging
35 mg delayed-release, oval-shaped, yellow tablets with “EC 35” engraved on one face carton of 4 blister packaged tablets

The ACTONEL DR tablet has an enteric coating, which delays the release of risedronate until the small intestine. The other formulations of ACTONEL are film coated, and must be taken before the first food of the day.