The Older Brain on Drugs: Substances That May Cause Cognitive Impairment

Jenny Rogers, MD; Bonnie S. Wiese, MD; Kiran Rabheru, MD, CCFP, FRCP


Geriatrics and Aging. 2008;11(5):284-289. 

In This Article


It is important to draw attention to polypharmacy, which increases the risk for the development of substance-induced impairment and for other adverse drug reactions. Multiple drug usage is common in all developed countries. In the U.S., polypharmacy is found in 40% of those older than 65 years.[47] Residents of long-term care facilities are a small but important group of patients who ingest many daily medications, taking an average of six to eight drugs daily.[48,49] Use of multiple medications with anticholinergic effects can increase patients' total anticholinergic burden as evidenced by clinical signs such as dry mouth, sedation, confusion and even hallucinations and delirium.[50] Use of medications that interfere with drug metabolism at the same cytochrome also elevates risk of cognitive adverse effects (e.g. CYP3A inhibitor, fluoxetine with alprazolam can increase risk of oversedation).[51] With a larger number of medications, it is understandable that there will be more drug reactions and interactions, and concomitant potential mental confusion or cognitive symptoms.


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