Fentanyl PCA Monotherapy and Fentanyl TTS Combination Therapy in Post-Operative Pain Management: Analyses of Spontaneous Adverse Drug Reaction Reports

ABSTRACT

OBJECTIVE: There have been many cases of spontaneous adverse drug reactions to fentanyl at a regional pharmacovigilance center in the hospital. To assess the factors causing the adverse drug reactions reported in patients receiving fentanyl patient-controlled analgesia (PCA) monotherapy or in combination with fentanyl transdermal therapeutic system (TTS) for acute post-operative pain management. METHODS: We conducted a retrospective cohort study with all patients prescribed fentanyl PCA for pain management after orthopedic surgery at a single university hospital from June 2012 to May 2013. We analysed the factors causing adverse drug reactions reported by a spontaneous reporting system in patients receiving fentanyl PCA monotherapy and those receiving fentanyl TTS in combination with fentanyl PCA. RESULTS: Based on the spontaneous adverse drug reaction reporting, the risk ratio for the incidence rate of adverse drug reaction in the fentanyl TTS combination therapy group was 3.04 (95 % CI: 2.4-4.00, P < 0.0001), which was approximately 3-fold higher than that reported for fentanyl PCA monotherapy. Only 60 % of the adverse drug reactions were reported. CONCLUSION: It is inappropriate to add fentanyl TTS to fentanyl PCA to manage post-operative acute pain. There is a need to improve adverse drug reaction reporting. We expect that regular analysis of adverse drug reactions reported at regional pharmacovigilance centre would aid in appropriate drug utilization by patients.