Background: Multiple lines of evidence suggest both dopaminergic and serotonergic involvement in the reinforcing effects of cocaine. Medications such as olanzapine, which block dopamine D2 receptors, as well as serotonin receptors 5HT2A and 5HT2C may be able to reduce cocaine use in cocaine dependent patients by reducing the euphoric effects of cocaine and attenuating cocaine craving.
Methods: This was a 12-week, double blind, placebo controlled, pilot trial involving 30 cocaine dependent subjects. Subjects received either olanzapine (10 mg/day) or identical placebo. Outcome measures included treatment retention, qualitative urine benzoylecgonine tests, cocaine craving, clinical global impression scores, and results from the addiction severity index.
Results: Treatment retention was slightly, but significantly, better in the placebo-treated subjects. Placebo-treated subjects were more likely to be abstinent from cocaine during the trial compared to olanzapine-treated subjects, based on urine benzoylecgonine results. Olanzapine was not superior to placebo in any outcome measure.
Conclusions: The results of this trial do not support the usefulness of olanzapine for the treatment of cocaine dependence. In fact, olanzapine may worsen cocaine treatment outcome.