Enuresis and urethral instability.

31 patients with refractory enuresis underwent simultaneous urethrocystometry. Pure urethral instability was encountered in 14, urethral and bladder instability in 11 and isolated uninhibited bladder in 3. This allows us to discuss the functional relationship between the urethra and the bladder. We consider urethral instability as being a trigger mechanism for detrusor contraction, and the explanation for the paradox of stable bladder enuresis. Phenylpropanolamine (Ornade), 25-50 mg at bedtime, stabilizes the vesicosphincteric unit and stopped bedwetting in 11 of 16 patients.