Effect of caffeine on urethral pressure.

Urethral pressure profiles have been a useful adjunct in the study of continence. Caffeine, a known smooth muscle inhibitor and skeletal muscle stimulator, is shown to decrease the urethral pressure profile in anesthetized dogs. This would lead one to believe that the smooth muscle component of urethral tonus is the determining factor. Discussions follow on the mechanism of caffeine action and the possible effect of caffeinated beverages on stress incontinence.