(289) Conditioned Pain Modulation in Buprenorphine-Maintained Patients with Opioid Use Disorder

The number of persons on buprenorphine maintenance for opioid use disorder (OUD) is rising and these patients often have chronic pain. It is not clear whether the endogenous analgesic system, which is often dysregulated in chronic pain patients, is affected by buprenorphine maintenance. Conditioned pain modulation (CPM) can evaluate endogenous analgesia; CPM is tested by applying a primary noxious stimulus alone and then simultaneously with a conditioning noxious stimulus on a remote body part. An efficient CPM results in an increase in primary pain threshold in the presence of the conditioning stimulus. A less efficient CPM is pro-nociceptive and results in lower primary pain threshold in the presence of the conditioning stimulus. This study assessed CPM in persons without chronic pain maintained on buprenorphine. CPM was tested by measuring pressure pain threshold at baseline and while undergoing a cold pressor test. Further, this study examined whether adjunct hydromorphone and/or buprenorphine, compared to placebo, effected CPM. Participants (N=13) with OUD who were maintained on 12mg or 16mg buprenorphine performed three study sessions, at least one week apart, where they underwent CPM at baseline and after cumulative doses of 32mg IV hydromorphone, 32mg IV buprenorphine, or placebo. Thirty-one percent of participants displayed less efficient CPM in at least one session prior to drug administration based on lower pressure pain threshold during cold-pressor testing compared to baseline. There were no significant differences in the proportion of individuals with less efficient CPM following 32mg IV hydromorphone (69%), 32mg buprenorphine (54%), or placebo (62%) (p=0.779). Results suggest that some buprenorphine-maintained individuals experience less efficient CPM. High doses of hydromorphone or buprenorphine did not improve CPM compared to placebo. Non-opioid analgesic strategies should be developed to address chronic pain in persons maintained on buprenorphine. Study medications provided by Indivior, Inc.