Comparison of acamprosate and placebo in long-term treatment of alcohol dependence

Abstract

Background: About 50% of alcoholic patients relapse within 3 months of treatment. Previous studies have suggested that acamprosate may help to prevent such relapse. The aim of our study was to assess the efficacy and safety of long-term acamprosate treatment in alcohol dependence.

Methods: In this multicentre, double-blind, placebo-controlled study, we recruited 455 patients, aged 18-65 years, with chronic or episodic alcohol dependence. Patients were randomly allocated treatment with acamprosate (1998 mg daily for bodyweight > 60 kg; 1332 mg daily for < or = kg) or placebo for 360 days. Patients were assessed on the day treatment started and on days 30, 90, 180, 270, and 360 by interview, self-report, questionnaire, and laboratory screening. Patients were classified as abstinent, relapsing, or non-attending. Time to first treatment failure (relapse or non-attendance) was the primary outcome measure.

Findings: Seven patients were excluded from the intention-to-treat analysis because they did not attend on the first treatment day and therefore received no medication. The acamprosate (n = 224) and placebo (n = 224) groups were well matched in terms of baseline demographic and alcohol-related variables. 94 acamprosate-treated and 85 placebo-treated patients completed the treatment phase: of those withdrawn, 104 (52 in each group) relapsed, 69 (33 vs 36, respectively) were lost to follow-up, 63 (31 vs 32) refused to continue treatment, 16 (15 vs 11) had concurrent illness, three (two vs one) died, ten (six vs four) had adverse side-effects, one (acamprosate treated) received the wrong medication, and three (placebo treated) were non-compliant. The proportion without treatment failure was higher in the acamprosate than in the placebo group throughout the treatment period (p < 0.001, Mantel-Cox). At the end of treatment, 41 (18.3%) acamprosate-treated and 16 (7.1%) placebo-treated patients had been continuously abstinent (p = 0.007). Mean cumulative abstinence duration was significantly greater in the acamprosate group than in the placebo group (138.8 [SD 137.5] vs 103.8 [119.0] days; p = 0.012). 148 patients (79 acamprosate, 69 placebo) completed 27 months follow-up: 27 (11.9%) acamprosate-treated and 11 (4.9%) placebo-treated patients remained continuously abstinent, and the mean cumulative abstinence duration was 230.8 days (259.1) and 183.0 days (235.2), respectively. Apart from occasional diarrhoea, there was no difference in side-effects between groups.

Interpretation: Acamprosate is an effective and well-tolerated pharmacological adjunct to psychosocial and behavioural treatment programmes for treatment of alcohol-dependent patients.