3.3.4. Adverse events
Serious adverse events were reported in both randomised trials. The trial by Kasper et al reported 48/308 (15.6%) SAEs in the pregabalin groups and 22/153 (14.4%) in the active control (lorazepam) (32). The Kasper et al study also reported one death within the intervention group, and it was not considered related to the study drug. (32) The trial by McDonald et al reported SAEs resulting across all medicine groups deprescribed and gabapentinoid specific SAEs are unclear. (31) Serious adverse events were not reported from the observational studies. (27, 28)
Adverse events were reported in both randomised trials. The Kasper et al trial reported 242/308 (78.6%) AEs in the pregabalin groups and 115/153 (75.2%) in the active control (lorazepam) (29). The most common adverse events being headache, dizziness and insomnia. (32) The other trial reported the most common adverse events for the entire study cohort, and did not specify gabapentinoid-specific adverse events. (31) Adverse events were not reported in the observational studies. (27, 28)
Only one study reported adverse events that resulted in participant withdrawal from the trial. (32) There were 50 adverse drug events that resulted in withdrawal from the study. (32) Information regarding the number and types of adverse events for the non-randomised controlled trials was not reported. Adverse Drug Withdrawal Events were reported in the study by McDonald, but gabapentinoid-related events are unclear.
Only one study reported details of rescue medicine use to manage symptoms. (32) Rescue medicine was permitted in one study of a gradual ‘rescue taper’ (i.e. extending the two-week tapering period of the participant’s allocated drug to four weeks) if participants experienced severe discontinuation symptoms during tapering periods and up to seven days afterwards. (32) A total of 39 (out of 615 randomised) participants required the extended rescue taper (10 participants in the high-dose (450 – 600 mg/d) pregabalin arm, 17 participants in the low-dose (150 – 300 mg/d) pregabalin arm, and 12 participants in the lorazepam control arm). (32)