Comparison of darifenacin and oxybutynin in patients with overactive bladder: assessment of ambulatory urodynamics and impact on salivary flow

Abstract

Objectives: To evaluate the effects of darifenacin, an M3 selective receptor antagonist, compared with oxybutynin, on ambulatory urodynamics, salivary flow, heart rate and visual nearpoint in patients with overactive bladder (OAB).

Methods: A double-blind, randomized, crossover study (n=65) with three treatment cohorts: darifenacin immediate release (IR) 2.5 mg three times a day (t.i.d.) or oxybutynin 2.5 mg t.i.d.; darifenacin controlled release (CR) 15 mg once daily (q.d.) or oxybutynin 5 mg t.i.d.; darifenacin CR 30 mg q.d. or oxybutynin 5 mg t.i.d. Within cohorts, patients received 7 days' treatment with each agent separated by 14 days' washout.

Results: All active treatments improved urodynamic parameters. Both darifenacin CR doses had significantly less effect on salivary flow than oxybutynin. Effects on urodynamic parameters, heart rate and visual nearpoint were comparable.

Conclusion: Ambulatory urodynamics appears to be an innovative and potentially useful investigative tool in the evaluation of the efficacy of new therapeutic agents. Darifenacin CR is an efficacious therapy for OAB with comparable effects on urodynamic parameters but producing significantly less dry mouth than oxybutynin.