• overactive bladder;
  • tolterodine;
  • oxybutynin;
  • placebo;
  • trial;
  • efficacy;
  • side effects


To compare extended-release (ER) tolterodine and immediate-release (IR) oxybutynin with placebo in Japanese and Korean patients with an overactive bladder (OAB).


Men and women aged ≥ 20 years with symptoms of urinary urgency, urinary frequency (≥ 8 micturitions/24 h), urge incontinence (≥ 5 episodes/week) and symptoms of OAB for ≥ 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.


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.


Tolterodine ER has similar efficacy but is better tolerated than oxybutynin IR in Japanese and Korean patients with OAB.