Introduction of low dose transdermal buprenorphine -- did it influence use of potentially addictive drugs in chronic non-malignant pain patients?

The aim was to study the introduction of the new low dose transdermal buprenorphine (LD-TD-BUP) in Norway, particularly with regard to former use and co-medication with other potentially addictive drugs. The nationwide Norwegian Prescription Database contains information on all prescription drugs dispensed to individual non-institutionalised patients, and we may follow all individuals who received LD-TD-BUP (Norspan) after marketing on the Norwegian market on 15/11/05. We studied all prescriptions of opioids and other potentially addictive drugs to patients receiving at least two LD-TD-BUP prescriptions during 2004-2006. Poisson regressions were run with concomitant use of addictive drugs (yes, no) as the endpoint. Overall, 1884, non cancer individuals received at least two prescription of LD-TD-BUP. Of these 91.7% received prescriptions of other opioids and 58.6% of them had also been prescribed benzodiazepines/carisoprodol before the prescription of LD-TD-BUP. Of the LD-TD-BUP users who received more than one prescription, 60% co-medicated with at least one other potentially addictive drug, and 24% with at least two. In the multivariate analysis, the variables associated with a higher likelihood of using co-medicated drugs were: previous use of benzodiazepines/carisoprodol relative risk RR=16.7 (95% CI 10.4-26.9), previous use of opioids RR=4.0 (1.9-8.7) and younger age 20-40 years RR=1.9 (1.6-2.3). So far, it is questionable whether the introduction of LD-TD-BUP actually has stabilised opioids consumption or whether it has complicated and increased the consumption of potentially addictive drugs.