Treatment of overactive bladder in the aging population: focus on darifenacin

Anticholinergics are commonly used in primary and secondary care settings for the treatment of overactive bladder syndrome. The number of anticholinergic drugs available on the market is increasing and various studies, both observational and randomized controlled trials, have evaluated effectiveness of the different preparations available. When anticholinergic therapy is prescribed, there is still uncertainty about which anticholinergic drugs are most effective, at which dose, and by which route of administration. There is also uncertainty about the role of anticholinergic drugs in different patient groups, particularly in the elderly. The rationale for using anticholinergic drugs in the treatment of overactive bladder syndrome is to block the parasympathetic acetylcholine pathway and thus abolish or reduce the intensity of detrusor muscle contraction. There are currently five recognized subtypes of muscarinic receptor; the M(1), M(2), and M(3) subtypes are of interest in bladder activity. Muscarinic receptors are found in other parts of the body, eg, in the gut, salivary glands, tear ducts. Side effects associated with non-selective antimuscarinics can be particularly distressing in the elderly. The development of bladder selective M(3) specific antagonists has the advantage of providing increased efficacy with minimal side effects. Darifenacin is one such preparation. The aim of this review is to assess the pharmacology, interactions and the safety and tolerability of darifenacin in the treatment of overactive bladder in the elderly population with particular reference to clinical trial data available.