Buprenorphine: duration of blockade of effects of intramuscular hydromorphone.

Six opioid-dependent in-patients were maintained on daily sublingual doses of buprenorphine at 2, 6, and 12 mg/day for five days at each dose in a randomized, balanced sequence. Placebo buprenorphine was substituted for the next three days, and challenge doses of the mu agonist hydromorphone were administered on the three days. Planned comparisons in a 3-factor ANOVA showed dose-dependent hydromorphone effects, significant blockade of 'high' by the 12 mg buprenorphine dose, and no differences on hydromorphone-induced 'high' across 72 h of active buprenorphine. The data suggest that the blockade by buprenorphine of 'high' persists for at least 72 h after the last dose of buprenorphine.