Harms of antimuscarinics for the treatment of overactive bladder in older adults: a systematic review and meta-analysis

Introduction: Overactive bladder (OAB) is a condition that negatively impacts 25% of the older adult population. Antimuscarinics are a treatment option for OAB and should be used with caution in older adults due to the potential for adverse drug events (ADEs). Previous systematic reviews and meta-analyses (SRMAs) for antimuscarinics did not differentiate based on age.

Objectives: To explore and evaluate harms (ADEs and treatment discontinuations) in adults 65 or older taking antimuscarinics for OAB.

Study Design: Systematic Review and Meta-analyses

Methods: Searches for randomized controlled trials (RCTs) along with sub-analyses and pooled analyses that compared antimuscarinics (oxybutynin, tolterodine, trospium, solifenacin, darifenacin, fesoterodine) to placebo or another antimuscarinic were performed using MEDLINE, EMBASE, SCOPUS, and Cochrane Central Register for Controlled Trials. Studies assessing harms in a population of adults 65 or older were included. 

Results: A total of 16 studies met the inclusion criteria (7 RCTs, 3 sub-analyses of RCTs, and 6 pooled analyses of RCTs). Eighty adverse events and 27 reasons for treatment discontinuation were explored. Adverse events and anticholinergic ADEs were more common in antimuscarinics compared to placebo. There were significantly higher rates of dizziness, dyspepsia, and urinary retention with fesoterodine, headache with darifenacin, and urinary tract infections with solifenacin. In head-to-head trials, subjects on solifenacin had less adverse events and dry mouth compared to subjects on oxybutynin immediate-release and subjects receiving fesoterodine had more adverse events and dry mouth when compared to tolterodine extended-release (ER). Discontinuation rates due to adverse events and dry mouth were higher in the antimuscarinics and fesoterodine groups when compared to placebo. In head-to-head trials, discontinuation rates due to adverse events were higher in fesoterodine compared to tolterodine ER.

Conclusions: Treatment for overactive bladder using antimuscarinics in adults aged 65 or older resulted in significant increase risk for several adverse events compared to placebo including anticholinergic and non-anticholinergic ADEs.