Data from these studies indicate that buprenorphine is efficacious in treating opioid dependence. It was possible to induct heroin addicts rapidly onto buprenorphine without precipitating an opioid withdrawal syndrome. A daily 8-mg SL dosage was sufficient to maintain individuals without producing reports of withdrawal symptoms. When buprenorphine was administered at the above dose every other day, however, mild withdrawal symptoms were reported, and responses to challenges with intravenously given hydromorphone appeared greater than when the challenges were given intramuscularly. From these results, the authors conclude that buprenorphine at this dose should be administered on a daily basis. These results are now being applied to a phase II outpatient clinical trial comparing buprenorphine with methadone.