In a placebo-controlled, randomized, double-blind, cross-over study, terodiline (50 mg/d) was compared with emepronium (600 mg/d) in 20 patients with motor urge incontinence. Evaluation of clinical efficacy was based on changes in micturition pattern, flow measurements, residual urine, cystometry and patient preferences, and safety on adverse reactions, blood chemistry, urine examinations and ECG. The number of voluntary micturitions decreased from a mean of 21.5 per 48 h on placebo by 1.6 on terodiline and 2.8 on emepronium. Involuntary micturitions decreased from 3.6 per 48 h by 1.3 on both treatments (p less than 0.05). The maximal flow rate decreased from a mean of 24.5 ml/sec to 19.6 ml/sec on emepronium and increased to 25.4 ml/sec on terodiline. Residual urine decreased from a mean of 54 ml to 49 ml on terodiline and increased to 60 ml on emepronium. Volume at first desire to void in the supine position increased on emepronium by 44 ml (p less than 0.05) and on terodiline by 3 ml, on the upright position by 11 ml and 18 ml, respectively. Bladder capacity increased in the supine position on emepronium by 32 ml and decreased on terodiline by 8 ml, in the upright position increased by 9 ml and 5 ml, respectively. The bladder pressure at first desire to void in the supine position increased on emepronium by 2 cmH2O, and decreased on terodiline by 2 cmH2O. The intravesical pressure at strong desire to void decreased on emepronium by 6 cmH2O and on terodiline by 7 cmH2O, in the upright position by 2 cmH2O and 1 cmH2O, respectively. 39% of the patients preferred terodiline, 39% emepronium and 22% placebo.(ABSTRACT TRUNCATED AT 250 WORDS)