Effects of buprenorphine versus buprenorphine/naloxone tablets in non-dependent opioid abusers

Rationale: Buprenorphine is an opioid a,agonist-antagonist under developmen t in the United States as a sublingual medication for treatment of opioid d ependence. Buprenorphine may be abused; therefore, tablets combining bupren orphine with naloxone have been developed with the intent of reducing the a buse risk in people physically dependent upon opioids. The characteristics and abuse potential of buprenorphine and buprenorphine/naloxone tablets in non-dependent opioid abusers have not been determined. Non-parenteral abuse of opioids such as buprenorphine may be mon likely in people who have less seven substance abuse disorders (e.g., an not physically dependent upon op ioids). Objectives: To assess the abuse potential of sublingual buprenorphi ne and buprenorphine/naloxone tablets in non-dependent opioid abusers. Meth ods: Subjects (n=7) were tested with subingual buprenorphine (4, 8, 16 mg), sublingual buprenolyhine/naloxone (1/0.25, 2/0.5, 4/1, 8/2, 16/3 mg), as w ell as intramuscular hydromorphone as an opioid agonist control (2, 4 mg) a nd placebo in laboratory sessions conducted twice per week. Dosing was doub le-blind and double-dummy. Results: The higher doses of both buprenorphine and buprenorphine/naloxone produced similar opioid agonist-like effects. Th e onset of these effects was slowed, consistent with the sublingual route o f administration, and the magnitude of effects was moderate. There was no e vidence to suggest the addition of naloxone attenuated buprenorphine's opio id agonist effects in this population when buprenorphine was delivered by t he sublingual route. Conclusions: These results suggest that sublingual bup renorphine and buprenorphine/naloxone may both be abused by opioid users wh o are not physically dependent upon opioids.