Drug-induced cognitive impairment

Katsuyoshi Mizukami

Graduate School of Comprehensive Human Sciences, University of Tsukuba

Drugs are a major cause of reversible cognitive impairment in the elderly. Factors aggravating cognitive impairment in individuals include a decrease in metabolism and excretion ability, change of the drug sensitivity, weakening of the blood-brain barrier, and organic brain disorders including dementia, while drug-related factors include polypharmacy, drug dose, permeability of the blood-brain barrier, and pharmacologic actions such as anticholinergic action and oversedation. Although various drugs can cause cognitive impairment, the most frequent of these are central nervous system drugs such as benzodiazepines, tricyclic anti-depressants, and phenothiazine.
To reduce the risk of drug-induced cognitive impairment in the elderly, it is important for physicians to try to minimize the number of prescribed drugs and to select safer drugs. It is also important to keep in mind that people with dementia, such as Alzheimer's disease and dementia with Lewy bodies, are specifically vulnerable to drug-induced cognitive impairment while using central nervous system drugs with anticholinergic actions for the treatment of behavioral and psychological symptoms of dementia. In pharmacotherapy for the elderly, it is always necessary to take possible drug-induced cognitive impairments into consideration.

Address correspondence to Dr. Katsuyoshi Mizukami, Graduate School of Comprehensive Human Sciences, University of Tsukuba (3-29-1 Otsuka, Bunkyo-ku, Tokyo 112-0012, Japan)