The misuse of buprenorphine and a buprenorphine-naloxone combination in Wellington, New Zealand.

Two surveys of 12 months duration were undertaken on opioid users presenting to the Wellington Alcohol and Drug Centre before and after the introduction of a combination buprenorphine 0.2 mg-naloxone 0.17 mg tablet (Bu-Nx), which was launched in 1991 in the hope of reducing intravenous misuse. There was considerable intravenous (i.v.) misuse of buprenorphine 0.2 mg tablets (Bu) in 1990 with self-reports of misuse in 81% of the patients over the 4 weeks prior to presentation, and 65% of the patients had buprenorphine in their urine. In the repeat survey 57% reported misuse of the Bu-Nx combination over the previous 4 weeks, and 43% had buprenorphine +/- naloxone detected in their urine. There was a reduction in the street price of Bu-Nx. One-third of the patients who used Bu-Nx i.v. reported instances of withdrawal symptoms, and subjectively the drug was less attractive to misusers. The combination product may have less misuse potential than buprenorphine alone, but it remains a preparation, in the dosages employed, that is intravenously misused.