A 6-month large-scale study into the safety of tamsulosin.

AIMS

Tamsulosin is an alpha1-adrenoceptor antagonist for the treatment of symptomatic benign prostatic hyperplasia with a tolerability similar to that of placebo in short-term, placebo-controlled studies with limited patient numbers. The present study was designed to test the safety of tamsulosin treatment in a large cohort of men during a prolonged period of time, particularly with regard to comedications.

METHODS

A multicentre, open-label phase IIIb study with 1784 patients receiving 0.4 mg o.d. tamsulosin for 6 months was performed according to good clinical practice guidelines. The analysis was performed on an intention-to-treat basis and powered to detect adverse events (AE) occurring in 0.15% of patients with 95% confidence.

RESULTS

During a total drug exposure time of 811 patient years, 386 AE were recorded in 253 patients (14.2%; 95% confidence intervals [CI] 12.0-15.2%). Twenty-nine patients suffered 44 serious AE including five fatal events (CI 0.12-0.73%) due to myocardial infarction (n = 3) and to pneumonia and a car accident (one each), but all deaths were judged to be unlikely to be related to study medication. The frequency of AE in patients without any comedication (n = 1095) was 13.0% (CI 11.3-14.9%). In a logistic regression analysis beta-adrenoceptor blockers, converting enzyme inhibitors, antidiabetics and diuretics did not significantly affect the odds ratio for having AE. However, concomitant alpha-adrenoceptor antagonists (a protocol violation) and treatment with verapamil (which also has alpha-adrenoceptor antagonist activity) significantly enhanced the odds ratio for having AE to 3.87 (CI 1.52-9.85) and 3.17 (CI 1.52-6.58), respectively. Minor increases in the odds ratio, which did not reach statistical significance, were also observed for Ca2+ antagonists other than verapamil and for nitrates.

CONCLUSIONS

We conclude that tamsulosin has a good safety profile relative to AE rates in the placebo arms of previous studies on tamsulosin even in the presence of most potentially complicating comedications. No major unexpected severe AE were recorded during our 6 months study.