Tamsulosin. A review of its pharmacological properties and therapeutic potential in the management of symptomatic benign prostatic hyperplasia.

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Tamsulosin is the first subtype-selective (alpha IA) alpha 1 adrenoceptor antagonist with specificity for prostatic alpha 1 adrenoceptors (alpha 1A adrenoceptors are thought to be involved in prostatic smooth muscle contraction) to become available for the treatment of patients with symptomatic benign prostatic hyperplasia (BPH). With tamsulosin, the incidence of adverse events commonly associated with alpha 1 adrenoceptor antagonism is similar to that with placebo (except for ejaculation disorders) and alfuzosin. The incidence of other adverse events is similar with tamsulosin and placebo. Furthermore, blood pressure and heart rate are not significantly affected by tamsulosin in patients with symptomatic BPH. In contrast, blood pressure is significantly reduced by alfuzosin compared with tamsulosin. Tamsulosin is available as a controlled release formulation suitable for once daily administration; dose titration is not required. The overall efficacy of this agent administered at a dosage of 0.1 to 0.4 mg/day in Japan, 0.4 mg/day in Europe and 0.4 to 0.8 mg/day in the US to patients with symptomatic BPH is greater than that of placebo was similar to that of alfuzosin or prazosin in the 2 available studies. Efficacy was primarily assessed by changes in maximum and average urinary flow rates, residual urinary volume and total symptom scores. Improvements in these parameters in short term trials (< or = 13 weeks) appear to be maintained in the longer term (< or = 60 weeks). Quality-of-life effects also appear to be similar with tamsulosin and alfuzosin. In conclusion, the pharmacodynamic properties of this agent appear to translate into tolerability and administration advantages over other alpha 1 adrenoceptor antagonists. If future investigations confirm its promising efficacy and tolerability, tamsulosin will be ideally placed as a valuable therapeutic option for patients with symptomatic BPH and in patients awaiting surgery or in those unable to undergo surgery.