Abuse liability of buprenorphine-naloxone tablets in untreated IV drug users.

Buprenorphine (Subutex) is widely abused in Finland. A combination of buprenorphine plus naloxone (Suboxone) has been available since late 2004, permitting a comparison of the abuse of the two products among untreated intravenous (IV) users. A survey was distributed to attendees at a Helsinki needle exchange program over 2-weeks in April, 2005, At least 30% were returned anonymously. Survey variables included: years of prior IV opioid abuse, years of buprenorphine abuse, frequency, dosage, route of administration and reasons for use, concomitant IV abuse of other substances and amount paid on the street for both buprenorphine and buprenorphine+naloxone. Buprenorphine was the most frequently used IV drug for 73% of the respondents. More than 75% said they used IV buprenorphine to self-treat addiction or withdrawal. Most (68%) had tried the buprenorphine+naloxone combination IV, but 80% said they had a "bad" experience. Its street price was less than half that of buprenorphine alone. The buprenorphine+naloxone combination appears to be a feasible tool, along with easier access to addiction treatment, for decreasing IV abuse of buprenorphine.