OBJECTIVE: We examined the immediate effect of a systemic nitric oxide augmentation on the bladder outlet resistance in healthy men.
METHODS: Eleven healthy male volunteers with a mean age of 25.5 yr were included in the study. They were prepared for a standard urodynamic study, and a baseline pressure-flow study was obtained. The subjects were then given 20 mg isosorbide dinitrate sublingually, and after refilling their bladder a second pressure-flow study was done after 20 min. The pressure-flow studies were then compared in regard to the average flow rate, the average detrusor pressure during micturition, and the detrusor pressure at maximum flow rate.
RESULTS: One of the subjects was unable to void and had to be excluded from the study. In the remaining 10 men, the mean average flow rate increased from 16.7 ml/s before to 20.2 ml/s after the intake of the NO donor (P=0.013). Concomitantly, the average detrusor pressure during micturition decreased from a mean of 57 to 52 cm H2O (P=0.004) and the mean detrusor pressure at maximum flow rate decreased from 60 to 52 cm H2O (P=0.013).
CONCLUSIONS: Systemic NO augmentation can lower the functional bladder outlet resistance very rapidly in men. Our results support the concept that the NO-cGMP pathway may be a promising target for medical treatment of lower urinary tract symptoms.