[Impact on cognitive function of anticholinergic drugs used for the treatment of overactive bladder in the elderly]

Describe the central nervous system (CNS) adverse effects of anticholinergic drugs used for the treatment of overactive bladder (OAB) in the elderly.

Relevant data from the literature were identified primarily through a Medline search of articles published through December 2013. The search terms included overactive bladder, central nervous system, elderly, anticholinergic, and antimuscarinic. Articles were chosen for inclusion based on their pertinence to the focus on treatment of OAB in the elderly.

Several anticholinergic drugs are available for the treatment of OAB, including oxybutinin, tolterodine, trospium chloride, solifenacine, fesoterodine. Among the agents reviewed, penetration of the blood-brain barrier (as predicted by lipophilicity, polarity, and molecular size and structure) is highest for oxybutinin, lower for tolterodine, solifenacine, and darifenacine, and lowest for fesoterodine and trospium chloride. Unwanted CNS adverse effects depend in part on patient specific variability in pharmacokinetic parameters, blood-brain barrier permeability, degree of cholinergic neuronal degeneration, total anticholinergic drug burden and patient's baseline cognitive status. The spectrum of anticholinergic CNS adverse effects ranges from drowsiness to hallucinations, severe cognitive impairment, and coma. Among the different anticholinergic agents, oxybutinin has been associated with cognitive impairment and trospium chloride and fesoterodine have shown favorable CNS tolerability.

Anticholinergic drugs improve significatively overactive bladder symptoms in older adults. However, potential CNS adverse effects of anticholinergic agents used in OAB must lead to a full evaluation before and during the treatment in order to evaluate benefice, risks and central side effects in this frail population.