Comparison of dry mouth in women treated with extended-release formulations of oxybutynin or tolterodine for overactive bladder.

The incidence, severity and tolerability of dry mouth was compared in 790 women with overactive bladder who were treated with extended-release oxybutynin chloride 10 mg/day or extended-release tolterodine tartrate 4 mg/day for 12 weeks in a multicenter, double-blind, parallel-group study. Dry mouth was the most common adverse event associated with treatment, with an incidence rate of 28.1% in the oxybutynin group and 21.6% in the tolterodine group (P = 0.039). The majority of dry mouth events were mild in both treatment groups. Severe dry mouth occurred in 1.5% and 0.5% of patients in the oxybutynin and tolterodine groups, respectively (P = 0.173). Seven patients on extended-release oxybutynin and 4 patients on extended-release tolterodine discontinued treatment due to dry mouth (P = 0.380). The results of this analysis showed that dry mouth was common with both treatments, but most events were mild; there was no difference in the rate of severe dry mouth or in the rate of withdrawal due to dry mouth.