Long-acting injectable bromocriptine does not reduce relapse in alcoholics

Dopamine is one of several neurotransmitters that may mediate alcohol intake and dependence. A randomized, double-blind, placebo-controlled international, multicentre study was conducted to assess the effects of a long-acting injectable preparation of bromocriptine, a dopamine agonist, (Parlodel-LAR) in reducing relapse in 366 moderately/severely dependent alcoholics (DSM-III-R), drinking approximately 200 g alcohol (14.5 standard drinks) per day. After detoxification they were randomized to receive six monthly injections of bromocriptine 25 mg (n = 120), bromocriptine 50 mg (n = 124), placebo (n = 122). Brief psychosocial treatment was allowed. At 6 months there were no significant differences between treatment groups in rates of relapse to any drinking or to drinking > or = 5 days per month and > or = 3 drinks per day. Pre-treatment alcohol intake did not determine response. Efficacy ratings by subjects and investigators and adverse events, reported by 51% of subjects, did not differ between treatments. The results of this large study, in which compliance was enhanced by Parlodel-LAR, do not indicate that bromocriptine is efficacious in the maintenance of abstinence or reduced drinking. Possible reasons for the discrepancy between these conclusions and those of some previous clinical trials, in which bromocriptine was reported to reduce symptoms of alcohol withdrawal and dependence, are discussed.