Antimuscarinic therapy in men with lower urinary tract symptoms: what is the evidence?

Lower urinary tract symptoms (LUTS) in men have, until recently, been assumed to arise from bladder outlet obstruction (BOO) caused by benign prostatic hyperplasia. Given this presumption, all manifestations (obstructive and irritative) of LUTS have been presumed to be responsive to therapy for prostatic disorders such as alpha-blockade (with or without the relatively recent addition of 5alpha-reductase inhibitors) or surgical intervention for benign prostatic hyperplasia. However, evidence demonstrates that persistence of irritative urinary symptoms is often encountered in men despite presumed adequate management of their obstructive complaints. Although antimuscarinic drugs have been found to be effective for irritative urinary symptoms attributed to the overactive bladder syndrome, concern regarding the use of this class of drugs in men with even potential coexistent BOO has limited the use of these drugs. Data are now accumulating that suggest that the antimuscarinic class may be used in men with bothersome, irritative symptoms, despite the presence of BOO (as defined by symptoms and urodynamics) and with a reasonable expectation of efficacy and little added risk. Critical evaluation of this evidence suggests that a role may exist for the antimuscarinic class in management of LUTS in men. However, areas of incomplete knowledge, including the risk associated with long-term (greater than 3 months) use of these drugs and the value of the antimuscarinic class as monotherapy in men with LUTS, still remain to be investigated.