The purpose of this study was to determine whether carvedilol, and alpha and beta adrenergic blocker, would inhibit the priming effect of cocaine in a laboratory model. A total of 12 subjects were enrolled in this double blind, placebo controlled, outpatient study. After an adaptation session, three experimental sessions were held, 2-9 days apart. On each of 3 experimental sessions, a single oral dose of low (25mg) or high dose of carvedilol (50mg) or placebo were administered. Two hours following carvedilol or placebo treatment, subjects received a priming dose of smoked cocaine, 0.4 mg/kg. during the second part of the session, subjects had the option to earn up to 2 tokens by working on a computer task that could later be exchanged for money or deliveries of cocaine. We proposed that blockage of adrenergic receptors by carvedilol would significantly alter the subjective and physiological effects of cocaine.