A double-blind, placebo-controlled pilot trial of acamprosate for the treatment of cocaine dependence

Background: Acamprosate is a medication shown to be effective for the treatment of alcohol dependence. Although the exact mechanism of action of acamprosate is unknown, evidence suggests that it decreases excitatory amino acid activity by post-synaptic inhibition of the NMDA subtype of glutamate receptors. It is possible that the activity of acamprosate via modulating glutamatergic activity could also reduce craving for cocaine and impact abstinence in cocaine dependence. Therefore, we conducted a double-blind placebo-controlled pilot trial of acamprosate for the treatment of cocaine dependence.

Methods: Sixty male and female cocaine dependent patients were included in a nine week double-blind, placebo-controlled trial. After a one-week baseline, patients were randomized to receive acamprosate 666 mg three times daily or identical placebo tablets for eight weeks. The primary outcome measure was cocaine use as determined by twice weekly urine drug screens.

Results: Thirty-six patients (60%) completed the trial, with no significant between-group difference in treatment retention. Percent cocaine positive urine drug screens did not differ between the two groups. Acamprosate was no better than placebo in reducing cocaine craving, reducing cocaine withdrawal symptoms, or improving measures of drug use severity from the Addiction Severity Index. Adverse events in this trial were generally mild and were evenly distributed between the two groups.

Discussion: Acamprosate was well tolerated but was no more efficacious than placebo in promoting abstinence from cocaine in cocaine dependent patients. Acamprosate does not appear to be a promising medication for the treatment of cocaine dependence.