Darifenacin: a muscarinic M3-selective receptor antagonist for the treatment of overactive bladder.

Darifenacin is a novel, muscarinic M(3)-selective receptor antagonist with up to 59-fold selectivity for M(3) receptors compared with other muscarinic receptor subtypes and a low relative affinity for M(1) and M(2) receptors. This profile may explain its clinical efficacy in overactive bladder (OAB), the observed absence of adverse effects on cognitive function and reduced cardiovascular risks. Large-scale clinical trials have confirmed that darifenacin 7.5 and 15 mg/day provide rapid and meaningful improvement across a range of OAB symptoms, but with CNS and cardiac adverse event rates comparable to placebo. On this basis, darifenacin seems to meet the standard for an effective OAB pharmacotherapy that is well-tolerated and, more importantly, minimises the risk of safety-related adverse effects.