A Phase II Trial of Varenicline for the Treatment of Cocaine Dependence

Background: Varenicline is a medication approved for the treatment of Tobacco Use Disorder. It is a partial agonist at α2β4 nicotinic acetyl choline receptors and a full agonist at α7 nicotinic acetyl choline receptors. By its effects on cholinergic activity at α7 and α2β4 receptors, varenicline may reduce dopaminergic and glutamatergic activity in the midbrain, and reduce symptoms of Cocaine Use Disorder. A preliminary trial of varenicline in human cocaine users suggested that varenicline treatment was associated with reductions in cocaine use. The current trial was intended to confirm these promising preliminary results. Methods: This was a 12-week, double blind, placebo controlled parallel group clinical trial involving 156 DSM IV cocaine dependent subjects. Subjects received 2 mg of varenicline or identical placebo each day along with weekly individual cognitive behavioral relapse prevention psychotherapy. The primary outcome measure was cocaine use measured by by thrice weekly urine drug screens. Additional outcome measures included cocaine withdrawal symptoms measured by the Cocaine Selective Severity Assessment (CSSA) End of study cocaine abstinence was analyzed using a Chi-square test.