Effect of intraurethral captopril gel on the recurrence of urethral stricture after direct vision internal urethrotomy: Phase II clinical trial.

OBJECTIVE: The purpose of this study is to evaluate the effect of intraurethral captopril gel as an antifibrotic agent on patients with urethral stricture. MATERIALS AND METHODS: In the first phase of clinical trial, 13 rabbits were included and local side-effects of captopril gel were evaluated. In the second phase, 56 patients were enrolled from April 2004 to January 2006. After internal urethrotomy the patients were classified into three patient groups: (i) received placebo gel (group I); (ii) received 0.1% captopril gel (group II); and (iii) instilled 0.5% captopril gel intraurethrally (group III). RESULTS: In phase I, no significant local side-effects were seen in the urethra of rabbits. In phase II, the mean age of the patients was 39.5 and the mean follow-up duration was 16 months. The most common etiology of the urethral stricture in the patients was iatrogenic (35.7%), most of their strictures had a depth of 0.5 cm or less (67.8%), and the length of most strictures was between 1 and 2 cm (41.1%). The patients' maximum urine flow increased more in groups II and III, than in group I (P < 0.04, P < 0.05, respectively). The recurrence rate was less in groups II and III than in group I (P < 0.05). In terms of the maximal urine flow and recurrence rate, no significant difference was seen between group II and group III (P = 0.13, P = 0.21, respectively). CONCLUSION: Captopril gel is a safe, effective and non-toxic agent for decreasing the recurrence rate of the urethral stricture after internal urethrotomy. However, more studies, including more cases and a longer follow up, are needed to prove the effect of captopril gel on patients' urethra.