The effect of sublingual isosorbide dinitrate on acute urinary retention due to benign prostatic hyperplasia

Acute urinary retention (AUR) is one of the most important long-term compli-cations of benign prostatic hyperplasia (BPH). Nitric oxide (NO) as a transmitter can relax smooth muscles of the bladder neck and external sphincter. Several studies have reported that sublingual isosorbide dinitrate (ISDN),as a NO donor,can lead to significant decrease in resting pressure of the external sphincter,and its rapid onset of action may be useful in the treatment of AUR. This study was designed to asses the effect of ISDN on AUR in patients with BPH. In this clinical trial,60 men with BPH-induced AUR were randomly selected via a simple sampling method. Participants were randomly divided into case and control groups. Patients in the case group received 200 mg of sublingual ISDN and participants in the control group received placebo. After 20 min,participants were asked to void spontaneously and the urine was collected in scale containers. Following this,urethral catheterization was done on all the participants and the residual urine was measured. Data were analyzed using SPSS version 15. There was no signi-ficant difference in the mean age of the two groups (P-value = 0.28). The mean voided urine volume in the case group was 201 mL and,in the control group,it was 18 mL (P = 0.004). About 30% in the case group and 3.3% in the control group could void spontaneously after receiving ISDN or placebo (P = 0.006). In the case group,there was a significant correlation between voided urine volume and total urine volume in the bladder (P = 0.03) and in the size of the prostate (P = 0.001). Our study shows that ISDN can be effective in the treatment of BPH-induced AUR with decrease in bladder outlet resistance. ISDN is more effective in younger men and in those with smaller prostates.