Mechanism: Acamprosate (Campral®) acts on the GABA and glutamate neurotransmitter systems and is thought to reduce symptoms of protracted abstinence such as insomnia, anxiety, restlessness, and dysphoria. It’s available in oral form (three times daily dosing).
Efficacy: Acamprosate increases the proportion of dependent drinkers who maintain abstinence for several weeks to months, a result demonstrated in multiple European studies and confirmed by a meta-analysis of 17 clinical trials. The meta-analysis reported that 36% of patients taking acamprosate were continuously abstinent at 6 months, compared with 23% of those taking a placebo. More recently, two large U.S. trials failed to confirm the efficacy of acamprosate, although secondary analyses in one of the studies suggested possible efficacy in patients who had a baseline goal of abstinence. A reason for the discrepancy between European and U.S. findings may be that patients in European trials had more severe dependence than patients in U.S. trials, a factor consistent with preclinical studies showing that acamprosate has a greater effect in animals with a prolonged history of dependence. In addition, before starting medication, most patients in European trials had been abstinent longer than patients in U.S. trials.
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