Effect of dantrolene sodium on the spastic external urethral sphincter recorded by sphincterometry.

An improved method of sphincterometry is described, which is easy to perform in men and also may be used in women. It gives reproducible results in the individual patient. The maximum pressure was found by radiographic and reflexological examinations of the external urethral sphincter. When 0.5 mg./kg. body weight dantrolene sodium was injected intravenously the resistance of the external urethral sphincter was found to be reduced significantly, presumably reflecting a reduction of reflex activity.