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

Aims Tamsulosin is an alpha (1)-adrenoceptor antagonist fur the treatment o f symptomatic benign prostatic hyperplasia with a tolerability similar to t hat of placebo in short-term. placebo-controlled studies with limited patie nt 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, part icularly with regard to comedications. Methods A multicentre, open-label phase IIIb study with 1784 patients recei ving 0.4 mg o.d. tamsulosin for 6 months was performed according to good cl inical practice guidelines. The analysis was performed on all 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 c ar accident (one each), hut all deaths were judged to be unlikely to be rel ated to study medication. The frequency of AE in patients without any comed ication (n = 1095) was 13.0% (CI 11.3-14.9%). In a logistic regression anal ysis beta -adrenoceptor blockers, converting enzyme inhibitors, antidiabeti cs 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 x-adrenoceptor antagonist ac tivity) significantly enhanced the odds ratio for having AE to 3.87 (CI 1.5 2-9.85) and 3.17 (CI 1.52-6.58), respectively. Miller increases ill the odd s ratio, which did not reach statistical significance, were also observed f or 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 amis of previous studies on tamsulosin even in t he presence of most potentially complicating comedications. No major unexpe cted severe AE were recorded during our 6 months study.