Acute effect of norfenefrine on the urethral pressure profile in females with genuine stress incontinence.

To study the acute effect of norfenefrine, given orally in aqueous solution, on the urethral closure function, profilometry was performed before and after administration of placebo and increasing doses of norfenefrine in 6 females with genuine stress incontinence. A weak increase in urethral pressure was observed after administration of 90 mg of norfenefrine. No changes in heart rate and blood pressure occurred. The results indicate that the direct sympathomimetic effect of norfenefrine is weak. It is suggested that norfenefrine mainly acts via indirect mechanisms.