Darifenacin: An M3-selective muscarinic antagonist for the treatment of overactive bladder

Darifenacin (Enablex, Novartis) is a muscarinic antagonist in phase 3 clinical trials for the treatment of overactive bladder (OAB). Darifenacin demonstrates relative selectivity for the M3 muscarinic receptor subtype over the M1 and M2 subtypes. In clinical trials, darifenacin has been compared to placebo for the treatment of symptoms of OAB in adult men and women. Patients treated with darifenacin experienced significantly greater reductions in the number of incontinence episodes per week, nocturnal awakenings, and warning time before micturitions. It appears to have similar efficacy to available anticholinergic agents for the treatment of OAB. Commonly reported adverse events include dry mouth and constipation, and preliminary data suggest that darifenacin may be associated with decreased impairment of salivary flow versus oxybutynin. Darifenacin has not been found to have an effect on the cardiovascular system or cognition in clinical trials. Further research is needed to determine the efficacy of darifenacin compared to other available anticholinergic agents such as oxybutynin and tolterodine, as well as emerging therapies. In addition, further investigation of the adverse effect profile in elderly patients is warranted.