Acamprosate adverse effects

Acamprosate is administered as 1-2 enteric-coated 333-mg tablets three times per day. It is poorly absorbed, and food reduces its absorption even further. Acamprosate is widely distributed and is eliminated renally. It does not appear to participate in drug-drug interactions. The most common adverse effects are gastrointestinal (nausea, vomiting, diarrhea) and rash. It should not be used in patients with severe renal impairment. 

In an open, single-blind, randomized study, naltrexone (50 mg/day) and acamprosate (1665-1998 mg/day) were used for 1 year by 157 recently detoxified alcohol-dependent men with moderate dependence (4). The time to first relapse was 63 days (naltrexone) and 42 days (acamprosate) after 1 year, 41% of those given naltrexone and 17% of those given acamprosate had not relapsed. Adverse effects were more common with naltrexone and were worse during the first 2 weeks of treatment. They included nausea (25 versus 4%), abdominal pain (23 versus 4%), drowsiness (35 versus 2%), headache (13 versus 6%), and nasal congestion (23 versus 7%). 

Naltrexone modestly increases the rate and extent of acamprosate absorption. There is no pharmacokinetic interaction between acamprosate and alcohol or diazepam. Disulflram does not alter the pharmacokinetics of acamprosate, and acamprosate does not alter the pharmacokinetics of imipramine. The combination of acamprosate and barbiturates, meprobamate, or oxazepam does not appear to increase the risk of adverse effects. 

A 15-day study in 591 patients, to assess the effects of the concurrent use of acamprosate with other drugs eommonly used in the management of alcohol withdrawal, found no evidence of additional adverse effeets with meprobamate, oxazepam, or the barbiturate complex tetrabamate (that includes phenobarbital). Other studies found that acamprosate eaused no clinically relevant ehanges in imipramine pharmacokinetics, and the pharmacokinetics of both diazepam and acamprosate were unchanged by concurrent use. ... 

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