alpha(1)-blockers for BPH: are there differences?

Abstract

alpha(1)-blockers are well established for the treatment of lower urinary tract symptoms (LUTS) suggestive of benign prostatic obstruction (BPO), previously referred to as benign prostatic hyperplasia (BPH). The various available alpha(1)-blockers do not differ in terms of their clinical efficacy, but there are several indications that alpha(1)-blockers differ qualitatively with regard to their cardiovascular safety and tolerability, albeit the quantification of these differences is subject to several constraints and pitfalls. Clinical selectivity, i.e. the capacity of separating between desired urological and undesired (actually redundant) cardiovascular alpha(1)-blockade is not unlikely to relate to pharmacological selectivity (the relative preference to block the alpha(1A)- and alpha(1D)-adrenoceptor subtypes in vitro, whilst hardly blocking alpha(1B)-adrenoceptors). On the other hand, both clinical and pharmacological selectivity are not unequivocally reflected by experiments on so-called functional selectivity (in vivo experiments that differentiate urological and cardiovascular effects). Generally, alpha(1)-blockers that are efficacious in hypertension (doxazosin, terazosin, alfuzosin) are more likely to impair safety-relevant, physiological blood pressure control in normotensives with LUTS than tamsulosin, which does not reduce elevated blood pressure in comparison with placebo and has little effect on orthostatic blood pressure control. However, clinical selectivity and cardiovascular safety are also defined by the treatment regimen (dose, dosage interval, formulation, step-up dose-increments for treatment initiation, etc.) and by relevant patient-treatment interactions (co-morbidity and co-medication in particular). On the basis of the available information, tamsulosin administered once daily at a dose of 0.4 mg after breakfast (without step-up increments) can be accepted as a highly convenient and efficacious way to treat LUTS with a low cardiovascular safety risk, i.e. with a high level of clinically selectivity. Copyrightz1999S. KargerAG,Basel