OBJECTIVE: The study examined the effectiveness of amantadine in reducing cocaine withdrawal symptoms and improving treatment outcome among cocaine-dependent patients in outpatient treatment. METHOD: Sixty-one cocaine-dependent subjects participated in a double-blind, placebo-controlled trial of amantadine. RESULTS: Among subjects with severe cocaine withdrawal symptoms at the start of treatment, those who received amantadine used significantly less cocaine during the trial than did subjects who received placebo. Compared to subjects who received placebo, subjects who received amantadine submitted significantly more benzoylecgonine-negative urine samples and used cocaine on significantly fewer days during the trial. CONCLUSIONS: Amantadine may be an effective treatment for cocaine-dependent patients with severe cocaine withdrawal symptoms.