Ritanserin in relapse prevention in abstinent alcoholics: results from a placebo-controlled double-blind international multicenter trial. Ritanserin in Alcoholism Work Group.

Ritanserin, a long-acting specific 5-HT2 receptor antagonist, revealed promising effects on alcohol intake behavior in both animal and preliminary human studies. To test its effectiveness in alcohol dependence this phase III clinical trial was initiated. In a placebo-controlled, randomized, double-blind international multicenter study 493 patients with moderate or severe alcohol dependence (DSM-III-R) were treated with three doses of ritanserin 2.5 mg/day (n = 122), 5 mg/day (n = 123), 10 mg/day (n = 126), or placebo (n = 122) over a period of 6 months. Ritanserin was well tolerated. The most frequent adverse experiences were headache and insomnia. A small increase in weight in the ritanserin-treated patients was observed. There were no significant differences between any dose of ritanserin and placebo in the relapse-rate, the time to relapse, craving for alcohol, or quantity and frequency of drinking after relapse. So far, neither ritanserin nor any other serotonergic medication has shown its specific effectiveness in relapse prevention in alcohol dependence.