Objective: To evaluate the efficacy of tamsulosin compared to placebo for treating catheterized patients with acute urinary retention (AUR) caused by benign prostatic hyperplasia (BPH), by comparing the numbers of patients who voided successfully after removing their catheter.
Patients and methods: This was a randomized, double-blind, placebo-controlled, parallel-group, multicentre study. Men with AUR secondary to BPH were catheterized and then, if they fulfilled the entry criteria, were randomly assigned to receive either 0.4 mg tamsulosin hydrochloride in a modified-release capsule once daily, or a placebo. After up to eight doses the catheter was removed and the ability to void unaided assessed.
Results: In all, 149 men (mean age 69.4 years) were randomly assigned to receive tamsulosin (75) or placebo (74); eight were not evaluable, so the intent-to-treat population was 141 men. Thirty-four men taking tamsulosin and 18 taking placebo did not require re-catheterization on the day of the trial without catheter (48% and 26% respectively, P = 0.011; odds ratio 2.47, 95% confidence interval, CI, 1.23-4.97). Success using free-flow variables was also higher in the men who received tamsulosin, at 37 (52%) vs 24 (34%) on placebo (P = 0.019; odds ratio 2.34, 95% CI 1.15-4.75). Withdrawals were high (120 men, 81%), mostly because of a need for re-catheterization (89 men, 60%). Dizziness and somnolence occurred in seven (10%) and four (6%) men who received tamsulosin, and two (3%) who received placebo, but overall the incidence of adverse events was similar in the two groups. One patient died from carcinomatosis.
Conclusion: Men catheterized for AUR can void more successfully after catheter removal if treated with tamsulosin, and are less likely to need re-catheterization. The side-effect profile was similar for tamsulosin and placebo, and consistent with known pharmacology. From these results tamsulosin can be recommended for treating men after catheterization for AUR, and can reduce the likelihood of the need for re-catheterization.