Buprenorphine-Naloxone abuse among participants in a needle exchange programme. A Finnish time-trend study from 2008 to 2018

Background: In Finland, buprenorphine has been the most common street opioid since the beginning of the 2000’s. A combination formulation buprenorphine-naloxone was developed to reduce abuse potential of monobuprenorphine via the injection route. Currently, buprenorphine-naloxone is the most commonly used in Finnish opioid agonist treatment. However, studies concerning buprenophine-naloxone abuse and associated factors are scarce1-3.

Research questions: How common is buprnorphine-naloxone abuse among i.v.-users attending a needle exchange programme, and what are the associating factors compared to monobuprenorphine abuse?

Methods: Information on substance use, including buprenorphine and buprenorphine-naloxone abuse, and socio-demographic background, was collected anonymously using questionnaires at four time-points (2008, 2011, 2014, 2018). Participants were i.v.-users attending a needle exchange program in Turku, Finland. Data on buprenorphine-naloxone abuse was available from 2008 (n=76, 68%male), 2011 (n=97, 68% male), 2014 (n=103, 57% male), and 2018 (n=97, 56% male).

Results: During the 10-year period, both buprenorphine (BUP) and buprenorphine-naloxone (BNX) abuse were common: 86%/66% in 2008; 85%/81% in 2011; 75%/81% in 2014; and 80%/73% in 2018. Daily abuse of BNX peaked in 2011: 50,5% of reported daily use during the past 6 months, then decreased between the years 2014-2018 (Figure 1). Of the BNX abusers, 85-100% abused also BUP. The respective figures for BUP abuse without BNX abuse varied from 8 to 23% during the 10-year period. Compared to BUP abuse, BNX abuse associated (adjusted with survey year) with amphetamine use (OR 3.0, 95%CI 1.4-6.6), methadone abuse (OR 5.6 95%CI 1.6-19.2), lower education level (OR 2.4, 95%CI 1.2-5.0), attending opioid agonist treatment (OR 4.0, 95%CI 1.2-13.5), and needle sharing (OR 3.2, 95%CI 1.5-6.8).

Conclusions: Buprenorphine-naloxone abuse is common among i.v.-users in South-Western Finland, where monobuprenorphine is the most commonly abused street opioid. Buprenorphine-naloxone abuse seems to associate with more disadvantaged i.v.-user profile compared to monobuprenorphine abuse, and this phenomenon should be addressed in future studies. Also, harm reduction strategies should be aimed for opioid users with buprenorphine-naloxone abuse.