Concomitant use of pregabalin with opioids and/or benzodiazepines is common, despite the increased risks. However, clinical trials suggest pregabalin can have an opioid-sparing effect when treating acute post-operative pain. We explored how opioid and benzodiazepine use changed over time in people initiating pregabalin, using dispensing claims data for a 10% sample of Australians (2013-19). Among 142,776 people initiating pregabalin (median age = 61 years, 57% female), we used group-based trajectory modelling to identify six pregabalin dose trajectories in the first year post-initiation. Two trajectories involved discontinuation: after one dispensing (49%), and after 6 months of treatment (14%). Four trajectories involved persistent use with variable estimated median daily doses of 39 mg (16%), 127 mg (14%), 276 mg (5%), and 541 mg (2%). We quantifed opioid and benzodiazepine use in the year before and after pregabalin initiation using generalised linear models. Over the study period, 71% were dispensed opioids and 34% benzodiazepines, with people on the highest pregabalin dose having highest rates of use. Opioid use increased post-pregabalin initiation. Among people using both opioids and pregabalin, the geometric mean daily dose in oral morphine equivalents increased after pregabalin initiation in all trajectories, ranging from +5.9% (99%CI 4.8%-7.0%) to +39.8% (99%CI 38.3%-41.5%) in people on the highest daily pregabalin dose. Among people using both pregabalin and benzodiazepines, the dose remained constant over time for people in all trajectories. Notwithstanding its reputation as opioid-sparing, in this outpatient setting we observed that people using opioids tended to use higher opioid daily doses after pregabalin initiation, especially those on high pregabalin doses.Copyright © 2021 International Association for the Study of Pain.
