The effect of transdermal opioid use on breakthrough opioid and sedative prescribing for rural patients with chronic pain in Northwest Tasmania: a longitudinal study

John Henshaw,¹ Judi Walker,² Dom Geraghty<sup>3

1</sup>Rural Clinical School, University of Tasmania, Hobart, TAS, ²School of Rural Health, Monash University, Melbourne, VIC, ³School of Human Life Sciences, University of Tasmania, Hobart, TAS, Australia

Purpose: The aim of the study reported here was to determine the frequency of prescribing of immediate-release (IR) opioids, and benzodiazepines, with both oral sustained-release (SR) and transdermal (TD) opioid maintenance treatment, in a rural population with chronic non-cancer pain (CNCP).
Subjects and methods: A longitudinal study measuring IR opioid and benzodiazepine dispensed prescriptions (scripts) by route of maintenance opioid administration over time (monthly for 1 year). Subjects were opioid-treated CNCP patients from Northwest Tasmania. The outcome measures of mean monthly scripts were analyzed using generalized estimating equations with robust standard errors.
Results: Details of 12,191 dispensed scripts were obtained from 140 subjects over 12 months. Mean monthly IR scripts with oral SR opioid maintenance were 0.21 (95% confidence interval [CI] 0.10; 0.32). With TD opioid maintenance, this was nonsignificantly lower (P = 0.06) at 0.04 (95% CI 0.00; 0.15). Mean monthly benzodiazepine scripts with oral SR opioids were 0.47 (95% CI 0.32; 0.62), and unchanged (P = 0.84) for TD opioids at 0.45 (95% CI 0.28; 0.62).
Conclusion: There was a nonsignificant trend toward reduced prescribing of IR opioids with TD opioid-maintained, compared with oral SR opioid-maintained, CNCP rural patients. Benzodiazepine prescribing was similar for both groups. The rationale for use and the provision of breakthrough opioid analgesia for CNCP patients are complex, both for patients and their prescribers, while the regular use of benzodiazepines compounds the sedation from the subjects' maintenance opioid. The prolonged analgesic affect of TD opioids may benefit rural and remote CNCP populations and reduce the risk of diversion associated with oral opioids.

Keywords: benzodiazepines, rural health, drug diversion, chronic non-cancer pain