Prevention of prolonged voiding problems after unexpected postoperative urinary retention: comparison of phenoxybenzamine and carbachol.

The efficacy of phenoxybenzamine and carbachol for the prevention of prolonged micturition problems was investigated in 160 consecutive patients with postoperative urinary retention. The patients were randomized into 3 groups: group 1-52 patients given 10 mg. phenoxybenzamine, group 2-55 who received 2 mg. carbachol and group 3-53 given a placebo. The drug was given orally twice daily for 3 days beginning immediately after the first catheterization. Only 17 per cent of the patients in group 1 had recurrent retention after the first catheterization compared to 49 per cent in group 2 and 57 per cent in group 3. Phenoxybenzamine is significantly more effective than carbachol or a placebo for the prevention of prolonged micturition problems in patients with unexpected urinary retention postoperatively.