A pilot study of full-dose ondansetron to treat heavy-drinking men withdrawing from alcohol in Brazil.

Ondansetron has emerged as a promising medication for the treatment of alcohol dependence, mainly among early-onset alcoholics. This research primarily aimed to evaluate the efficacy and safety of ondansetron at a 16mg/day dosage to treat alcohol-dependent outpatients. A double-blind, placebo-controlled, 12-week study was carried out at the University of São Paulo, Brazil. The total sample comprised 102 men, 18-60 years of age, with an International Classification of Diseases (ICD-10) diagnosis of alcohol dependence. Half of our sample discontinued the treatment and the main outcome measures (proportion of abstinent days and proportion of heavy drinking days) were analyzed using the treatment adherents as well as with an imputed sample. The main factors associated with treatment retention were older age and smoking status. Although there were no significant differences between the main outcome measures of both medication groups in the adherents, ondansetron demonstrated a slight but significant superiority over the placebo regarding the proportion of heavy drinking days in the imputed sample (7.8% versus 11.7%, respectively). It appears that the optimal dosage to treat alcoholism has yet to be determined. Further, ondansetron may only be useful in treating some types of alcoholics. Ondansetron was well tolerated and no serious adverse events were registered.