Tamsulosin: the United States trials.

Overall, tamsulosin has several advantages. Its long-acting action allows for once-daily dosing. The therapeutic effect, as indicated by > 30% increase in peak urinary flow rate, is realized in more than 50% of the patients receiving the therapy. The beneficial effect from treatment is seen as early as 2 to 3 weeks after the maximum dose is reached. In addition, the dose may be adjusted from 0.4 mg daily to 0.8 mg daily to obtain the desired decrease in urinary tract obstructive symptoms, although the vast majority of patients are effectively treated with 0.4 mg daily. Also, there is no known effect of alpha 1-adrenergic antagonists on the serum PSA concentration. The incidence of untoward cardiovascular system effects is less important because of tamsulosin's uroselective action. As with any other medical therapy for BPH, tamsulosin must be taken indefinitely to maintain the therapeutic effect.