Buprenorphine, a mixed opioid agonist/antagonist, has been examined not only for the treatment of opioid dependence, but also for concurrent dependence on both opioids and cocaine. Preliminary human studies have suggested that buprenorphine treatment may be associated with significantly less cocaine abuse than is treatment with methadone maintenance. Preclinical studies in both primates and rodents have also indicated that buprenorphine may reduce cocaine self-administration and attenuate place preference for cocaine. Two double-blind, randomized clinical trials comparing buprenorphine with methadone have failed to demonstrate that buprenorphine is superior to methadone in reducing cocaine abuse. However, the trial by Kosten and associates has suggested a larger reduction in cocaine abuse at 6 mg than at 2 mg daily of buprenorphine. This dose dependence is consistent with cocaine challenge studies in which buprenorphine attenuated cocaine effects at 4 mg, but not at 2 mg, daily.