Acamprosate Calcium

1 INDICATIONS AND USAGE Acamprosate calcium delayed-release tablets are indicated for the maintenance of abstinence from alcohol in patients with alcohol dependence who are abstinent at treatment initiation. Treatment with acamprosate calcium delayed-release tablets should be part of a comprehensive management program that includes psychosocial support. The efficacy of acamprosate calcium delayed-release tablets in promoting abstinence has not been demonstrated in subjects who have not undergone detoxification and not achieved alcohol abstinence prior to beginning acamprosate calcium delayed-release tablets treatment. The efficacy of acamprosate calcium delayed-release tablets in promoting abstinence from alcohol in polysubstance abusers has not been adequately assessed. • Acamprosate calcium delayed-release tablets are indicated for the maintenance of abstinence from alcohol in patients with alcohol dependence who are abstinent at treatment initiation ( 1 , 14 ). • Treatment with acamprosate calcium delayed-release tablets should be part of a comprehensive management program that includes psychosocial support ( 1 ).

2 DOSAGE AND ADMINISTRATION The recommended dose of acamprosate calcium delayed-release tablets is two 333 mg tablets (each dose should total 666 mg) taken three times daily. A lower dose may be effective in some patients. Although dosing may be done without regard to meals, dosing with meals was employed during clinical trials and is suggested in those patients who regularly eat three meals daily. Treatment with acamprosate calcium delayed-release tablets should be initiated as soon as possible after the period of alcohol withdrawal, when the patient has achieved abstinence, and should be maintained if the patient relapses. Acamprosate calcium delayed-release tablets should be used as part of a comprehensive psychosocial treatment program. Recommended dose: 666 mg (two 333 mg tablets) taken three times daily ( 2 ). Dose reduction to one 333 mg tablet taken three times daily for patients with moderate renal impairment (creatinine clearance 30 mL/min to 50 mL/min) ( 2.1 ). Acamprosate calcium delayed-release tablets are contraindicated in patients with severe renal impairment (creatinine clearance of ≤30 mL/min) ( 2.1 , 4.2 , 5.1 , 8.6 , 12.3 ). 2.1 Dosage in Renal Impairment For patients with moderate renal impairment (creatinine clearance of 30 mL/min to 50 mL/min), a starting dose of one 333 mg tablet taken three times daily is recommended. Acamprosate calcium delayed-release tablets are contraindicated in patients with severe renal impairment (creatinine clearance of ≤ 30 mL/min) [see Contraindications (4.2) , Warnings and Precautions (5.1) , Use in Specific Populations (8.6) , and Clinical Pharmacology (12.3) ] .

3 DOSAGE FORMS AND STRENGTHS Acamprosate Calcium Delayed-Release Tablets are available containing 333 mg of acamprosate calcium, USP (equivalent to 300 mg of acamprosate). • The 333 mg tablets are white, enteric-coated, round, unscored tablets imprinted with M over AC in black ink on one side of the tablet and plain on the other side. Enteric-coated tablets, 333 mg ( 3 ).

4 CONTRAINDICATIONS • Acamprosate calcium delayed-release tablets are contraindicated in patients who previously have exhibited hypersensitivity to acamprosate calcium or any of its components ( 4.1 ). • Acamprosate calcium delayed-release tablets are contraindicated in patients with severe renal impairment ( 4.2 ). 4.1 Hypersensitivity to Acamprosate Calcium Acamprosate calcium delayed-release tablets are contraindicated in patients who previously have exhibited hypersensitivity to acamprosate calcium or any of its components. 4.2 Severe Renal Impairment Acamprosate calcium delayed-release tablets are contraindicated in patients with severe renal impairment (creatinine clearance of ≤ 30 mL/min) [ see Dosage and Administration (2.1) , Warnings and Precautions (5.1) , Use in Specific Populations (8.6) , and Clinical Pharmacology (12.3) ].

6 ADVERSE REACTIONS Common adverse events that occurred in any acamprosate calcium treatment group at a rate of 3% or greater and greater than the placebo group in controlled clinical trials with spontaneously reported adverse events are: accidental injury, asthenia, pain, anorexia, diarrhea, flatulence, nausea, anxiety, depression, dizziness, dry mouth, insomnia, paresthesia, pruritus and sweating ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Glenmark Pharmaceuticals Inc., USA at 1 (888) 721-7115 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. Clinically significant serious adverse reactions associated with acamprosate calcium described elsewhere in labeling include suicidality and depression and acute kidney failure [s ee Warnings and Precautions (5.2) , and Adverse Reactions (6.2) ]. The adverse event data described below reflect the safety experience in over 7000 patients exposed to acamprosate calcium for up to one year, including over 2000 acamprosate calcium-exposed patients who participated in placebo-controlled trials. Adverse Events Leading to Discontinuation In placebo-controlled trials of 6 months or less, 8% of acamprosate calcium-treated patients discontinued treatment due to an adverse event, as compared to 6% of patients treated with placebo. In studies longer than 6 months, the discontinuation rate due to adverse events was 7% in both the placebo-treated and the acamprosate calcium-treated patients. Only diarrhea was associated with the discontinuation of more than 1% of patients (2% of acamprosate calcium-treated vs. 0.7% of placebo-treated patients). Other events, including nausea, depression, and anxiety, while accounting for discontinuation in less than 1% of patients, were nevertheless more commonly cited in association with discontinuation in acamprosate calcium-treated patients than in placebo-treated patients. Common Adverse Events Reported in Controlled Trials Common adverse events were collected spontaneously in some controlled studies and using a checklist in other studies. The overall profile of adverse events was similar using either method. Table 1 shows those events that occurred in any acamprosate calcium treatment group at a rate of 3% or greater and greater than the placebo group in controlled clinical trials with spontaneously reported adverse events. The reported frequencies of adverse events represent the proportion of individuals who experienced, at least once, a treatment-emergent adverse event of the type listed, without regard to the causal relationship of the events to the drug. Table 1. Events Occurring at a Rate of at Least 3% and Greater than Placebo in any Acamprosate Calcium Treatment Group in Controlled Clinical Trials with Spontaneously Reported Adverse Events. Body System/Preferred Term Number of Patients (%) with Events Acamprosate Calcium 1332 mg/day Acamprosate Calcium 1998 mg/day 1 Acamprosate Calcium Pooled 2 Placebo Number of patients in Treatment Group 397 1539 2019 1706 Number (%) of patients with an AE 248 (62%) 910 (59%) 1231 (61%) 955 (56%) Body as a Whole 121 (30%) 513 (33%) 685 (34%) 517 (30%) Accidental Injury*† 17 (4%) 44 (3%) 70 (3%) 52 (3%) Asthenia 29 (7%) 79 (5%) 114 (6%) 93 (5%) Pain 6 (2%) 56 ( 4%) 65 (3%) 55 (3%) Digestive System 85 (21%) 440 (29%) 574 (28%) 344 (20%) Anorexia 20 (5%) 35 (2%) 57 (3%) 44 (3%) Diarrhea 39 (10%) 257 (17%) 329 (16%) 166 (10%) Flatulence 4 (1%) 55 (4%) 63 (3%) 28 (2%) Nausea 11 (3%) 69 (4%) 87 (4%) 58 (3%) Nervous System 150 (38%) 417 (27%) 598 (30%) 500 (29%) Anxiety††** 32 (8%) 80 (5%) 118 (6%) 98 (6%) Depression 33 (8%) 63 (4%) 102 (5%) 87 (5%) Dizziness 15 (4%) 49 (3%) 67 (3%) 44 (3%) Dry mouth 13 (3%) 23 (1%) 3 …

7 DRUG INTERACTIONS Acamprosate does not affect the pharmacokinetics of alcohol. The pharmacokinetics of acamprosate are not affected by alcohol, diazepam, or disulfiram, and clinically important interactions between naltrexone and acamprosate were not observed [ see Clinical Pharmacology ( 12.3 ) ].

8 USE IN SPECIFIC POPULATIONS • Pregnancy: Acamprosate calcium delayed-release tablets should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus ( 8.1 ). • Nursing Mothers: Caution should be exercised when acamprosate calcium delayed-release tablets are administered to a nursing woman ( 8.3 ). • Renal Impairment: Dose reduction required for moderate renal impairment; contraindicated in severe renal impairment ( 2.1 , 4.2 , 5.1 , 8.6 , 12.3 ) 8.1 Pregnancy Pregnancy Category C Teratogenic Effects Acamprosate calcium has been shown to be teratogenic in rats when given in doses that are approximately equal to the human dose (on a mg/m 2 basis) and in rabbits when given in doses that are approximately 3 times the human dose (on a mg/m 2 basis). Acamprosate calcium produced a dose-related increase in the number of fetuses with malformations in rats at oral doses of 300 mg/kg/day or greater (approximately equal to the maximum recommended human daily (MRHD) oral dose on a mg/m 2 basis). The malformations included hydronephrosis, malformed iris, retinal dysplasia, and retroesophageal subclavian artery. No findings were observed at an oral dose of 50 mg/kg/day (approximately one-fifth the MRHD oral dose on a mg/m 2 basis). An increased incidence of hydronephrosis was also noted in Burgundy Tawny rabbits at oral doses of 400 mg/kg/day or greater (approximately 3 times the MRHD oral dose on a mg/m 2 basis). No developmental effects were observed in New Zealand white rabbits at oral doses up to 1000 mg/kg/day (approximately 8 times the MRHD oral dose on a mg/m 2 basis). The findings in animals should be considered in relation to known adverse developmental effects of ethyl alcohol, which include the characteristics of fetal alcohol syndrome (craniofacial dysmorphism, intrauterine and postnatal growth retardation, retarded psychomotor and intellectual development) and milder forms of neurological and behavioral disorders in humans. There are no adequate and well controlled studies in pregnant women. Acamprosate calcium delayed-release tablets should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Nonteratogenic Effects A study conducted in pregnant mice that were administered acamprosate calcium by the oral route starting on Day 15 of gestation through the end of lactation on postnatal day 28 demonstrated an increased incidence of still-born fetuses at doses of 960 mg/kg/day or greater (approximately 2 times the MRHD oral dose on a mg/m 2 basis). No effects were observed at a dose of 320 mg/kg/day (approximately one-half the MRHD dose on a mg/m 2 basis). 8.2 Labor and Delivery The potential for acamprosate calcium delayed-release tablets to affect the duration of labor and delivery is unknown. 8.3 Nursing Mothers In animal studies, acamprosate was excreted in the milk of lactating rats dosed orally with acamprosate calcium. The concentration of acamprosate in milk compared to blood was 1.3:1. It is not known whether acamprosate is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when acamprosate calcium delayed-release tablets are administered to a nursing woman. 8.4 Pediatric Use The safety and efficacy of acamprosate calcium delayed-release tablets have not been established in the pediatric population. 8.5 Geriatric Use Forty-one of the 4234 patients in double-blind, placebo-controlled, clinical trials of acamprosate calcium delayed-release tablets were 65 years of age or older, while none were 75 years of age or over. There were too few patients in the ≥ 65 age group to evaluate any differences in safety or effectiveness for geriatric patients compared to younger patients. This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased …

12.1 Mechanism of Action The mechanism of action of acamprosate in maintenance of alcohol abstinence is not completely understood. Chronic alcohol exposure is hypothesized to alter the normal balance between neuronal excitation and inhibition. In vitro and in vivo studies in animals have provided evidence to suggest acamprosate may interact with glutamate and GABA neurotransmitter systems centrally, and has led to the hypothesis that acamprosate restores this balance.

11 DESCRIPTION Acamprosate calcium delayed-release tablets are supplied as an enteric-coated tablet for oral administration. Acamprosate calcium is a synthetic compound with a chemical structure similar to that of the endogenous amino acid homotaurine, which is a structural analogue of the amino acid neurotransmitter γ-aminobutyric acid and the amino acid neuromodulator taurine. Its chemical name is calcium acetylaminopropane sulfonate. Its chemical formula is C 10 H 20 N 2 O 8 S 2 Ca and molecular weight is 400.48 g/mol. Its structural formula is: Acamprosate calcium, USP is white or almost white powder. It is freely soluble in water, practically insoluble in alcohol and in methylene chloride. Each acamprosate calcium delayed-release tablet contains acamprosate calcium, USP 333 mg, equivalent to 300 mg of acamprosate. Inactive ingredients in acamprosate calcium delayed-release tablets include: colloidal silicon dioxide, crospovidone, magnesium silicate, magnesium stearate, methacrylic acid and ethyl acrylate copolymer dispersion, microcrystalline cellulose, povidone, propylene glycol, sodium starch glycolate, and talc. In addition, the black imprinting ink for the tablets contains ammonium hydroxide, black iron oxide, propylene glycol and shellac glaze. Sulfites were used in the synthesis of the drug substance and traces of residual sulfites may be present in the drug product. Structure.jpg

10 OVERDOSAGE In all reported cases of acute overdosage with acamprosate calcium delayed-release tablets (total reported doses of up to 56 grams of acamprosate calcium), the only symptom that could be reasonably associated with acamprosate calcium delayed-release tablets was diarrhea. Hypercalcemia has not been reported in cases of acute overdose. A risk of hypercalcemia should be considered in chronic overdosage only. Treatment of overdose should be symptomatic and supportive.

16 HOW SUPPLIED/STORAGE AND HANDLING Acamprosate Calcium Delayed-release Tablets, 333 mg are white to off-white, round, biconvex, beveled edge, enteric coated tablets, debossed with '569' on one side and plain on the other side and are supplied as follows: NDC 68382-569-06 in bottles of 30 tablets with child-resistant closure NDC 68382-569-16 in bottles of 90 tablets with child-resistant closure NDC 68382-569-01 in bottles of 100 tablets with child-resistant closure NDC 68382-569-28 in bottles of 180 tablets with child-resistant closure NDC 68382-569-05 in bottles of 500 tablets NDC 68382-569-10 in bottles of 1000 tablets Storage and Handling Store at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature]. Dispense in a tight container (USP).