Anticholinergic Drugs Linked to Cognitive Impairment

A new long-term study confirms that medications with anticholinergic activity cause cognitive impairment, and also identifies a possible link between these drugs and an increased risk of death.

Researchers at the University of East Anglia (Norwich, United Kingdom), the UK Medical Research Council (MRC; London, United Kingdom), and other institutions participating in the Cognitive Function and Aging Studies (CFAS)--a large longitudinal multicenter study--examined whether the use of medications with possible or definite anticholinergic activity increases the risk of cognitive impairment and mortality in older people, and whether the risk is cumulative. Study participants included 13,004 community-dwelling and institutionalized participants aged 65 and older between 1991 and 1993. The main outcome measure was decline in the Mini-Mental State Examination (MMSE) score at two years.

The results showed that at baseline, 47% of the population used a medication with possible anticholinergic properties, and 4% used a drug with definite anticholinergic properties. After adjusting for age, sex, educational level, social class, number of non-anticholinergic medications, number of comorbid health conditions, and cognitive performance at baseline, use of medication with definite anticholinergic effects was associated with a 0.33-point greater decline in MMSE score than not taking anticholinergics, whereas the use of possible anticholinergics at baseline was not associated with further decline. Two-year mortality was greater for those taking definite and possible anticholinergics. The study was published early online in the June 24, 2011, in the Journal of the American Geriatrics Society.

“We found that taking anticholinergic medications was linked to cognitive impairment, and for the first time to death,” said study corresponding author psychiatrist Chris Fox, MD, of the University of East Anglia. “We need follow-up to determine the degree to which anticholinergics are being prescribed for diseases with significant risk of death and the impact of that on our findings.”

Anticholinergics work by blocking acetylcholine, a nervous system neurotransmitter. They are divided into three categories in accordance with their specific targets in the central and/or peripheral nervous system: antimuscarinic agents, ganglionic blockers, and neuromuscular blockers. Over-the-counter anticholinergics are sold under various brand names such as Benadryl, Dramamine, Excedrin PM, Nytol, Sominex, Tylenol PM, Paxil, Detrol, and Demerol.

Related Links:
University of East Anglia
UK Medical Research Council