Clinical efficacy and tolerability of extended-release tolterodine and immediate-release oxybutynin in Japanese and Korean patients with an overactive bladder: a randomized, placebo-controlled trial

OBJECTIVE To compare extended-release (ER) tolterodine and immediate-release (IR) oxybutynin with placebo in Japanese and Korean patients with an overactive bladder (OAB). PATIENTS AND METHODS Men and women aged greater than or equal to 20 years with symptoms of urinary urgency, urinary frequency (greater than or equal to 8 micturitions/24 h), urge incontinence (greater than or equal to 5 episodes/week) and symptoms of OAB for greater than or equal to 6 months were randomized to double-blind treatment with tolterodine ER 4 mg once daily, oxybutynin IR 3 mg three times daily or placebo for 12 weeks. Efficacy assessments included changes from baseline in numbers of incontinence episodes per week, voids/24 h and mean volume voided/void. Patient perceptions of bladder condition, urgency and treatment benefit were also assessed. RESULTS In all, 608 patients were randomized to treatment with tolterodine (240), oxybutynin (246) or placebo (122). More patients prematurely withdrew on oxybutynin (23%) than with tolterodine (10.4%) or placebo (16.4%). After 12 weeks of treatment, the median number of incontinence episodes/week was reduced significantly more in the tolterodine (79%; P= 0.0027) and oxybutynin groups (76.5%; P= 0.0168) than on placebo (46.4%). There were also significantly greater improvements in the number of voids/24 h and volume voided/void with tolterodine and oxybutynin than with placebo. More patients in the tolterodine and oxybutynin than in the placebo groups reported improvements in perceived bladder condition, ability to hold urine and treatment benefit. Patients treated with oxybutynin reported more adverse events than those treated with tolterodine or placebo. Dry mouth was significantly more common with oxybutynin than with tolterodine (53.7% vs. 33.5%; P < 0.001), and occurred in 9.8% of placebo patients. CONCLUSION Tolterodine ER has similar efficacy but is better tolerated than oxybutynin IR in Japanese and Korean patients with OAB.