[How do medications used to treat urinary incontinence affect the cerebral function of the elderly?]

Anticholinergic agents are used for treatment of overactive bladder syndrome (OAB) by competitive blockade of acetylcholine at the muscarinic receptor. At present five different subtypes of M-receptors can be differentiated. Primary detrusor effects are mediated by M3-receptors as are side effects like dry mouth and constipation. Cardiac and central nervous system side effects appear to be M2 or M1 related. OAB symptom relief by the unselective drugs tolterodine, oxybutynin or trospium chloride and by M3-selective agents like darifenacin or solifenacin seems to be rather similar. Central side effects are different depending on gastrointestinal reabsorption, serum metabolism and penetration of the blood-brain barrier. Slow release formulations may be better tolerated. Anticholinergics that penetrate the blood-brain barrier may cause cognitive imbalance in older patients, as recent studies have shown for oxybutynin. Here M3-selective agents may offer an advantage.