Baclofen and severe alcohol dependence: an uncertain harm-benefit balance as of early 2013

Alcohol dependence is a severe, chronic illness. Even the best-assessed drugs used to maintain abstinence are poorly effective. Some patients remain dependent after several treatment attempts. Baclofen has been tested for its capacity to reduce craving for alcohol. We reviewed the data available as of early 2013, using the standard Prescrire methodology, in order to assess the harm-benefit balance of baclofen in maintaining abstinence or moderation in alcohol-dependent patients. Two double-blind, randomised, placebo-controlled trials conducted by the same team tested baclofen 30 mg/day in 123 alcohol-dependent patients referred to alcohol treatment centres. After 1 or 3 months of followup, more patients remained abstinent in the baclofen group than in the placebo group. In another double-blind, randomised trial, baclofen 30 mg/day was not more effective than placebo in 80 alcohol-dependent patients recruited through advertisements, many of whom were seeking treatment for the first time. Three uncontrolled retrospective series reported the results obtained in 300 alcohol-dependent patients, most of whom were in treatment failure. They were treated with high, escalating doses of baclofen (on average about 150 mg per day, up to 400 mg per day) with the intention of reducing their craving for alcohol. After 3 to 24 months of follow-up, about half of the patients reported moderate or zero alcohol consumption. At moderate doses, baclofen has been used since the 1970s in the treatment of certain forms of muscle spasticity. The main adverse effects reported in this setting were drowsiness (especially early during treatment) and various neuropsychiatric disorders such as dizziness, euphoria, depression, headache, paraesthesias, speech disorders, ataxia and insomnia. The adverse effects of high-dose baclofen are mainly based on monitoring of hundreds of alcohol-dependent patients, 69 reports to French pharmacovigilance centres in 2011, and cases of overdose or accidental ingestion reported to French poison control centres. Confusion and mania were reported, and coma occurred with doses of 200 mg or more. Some data point to an increased risk of suicide. In practice, in early 2013, more data are needed on the efficacy and adverse effects of baclofen in alcohol dependence, compared with other options. Patients who have received thorough, well-balanced information, and decide to try baclofen as a last resort should be included in comparative clinical studies.