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Common Drugs Affect Memory in Older Adults


Commonly used prescription and over-the-counter drugs can cause memory problems and other cognitive impairments in older adults. These drugs include many that older adults take on a regular basis for conditions ranging from urinary incontinence to depression, sleep problems, allergies, respiratory conditions, and acid reflux.

According to a study recently published in Clinical Interventions in Aging, a long list of drugs have been linked with causing cognitive difficulties, including problems with memory, concentration, and delirium. The authors arrived at this conclusion by reviewing 27 studies that had addressed this problem.

The drugs in question belong to a class called anticholinergics. These drugs are given to block the actions of the neurotransmitter acetylcholine in the central and peripheral nervous systems. Acetylcholine helps with learning, memory, and concentration, as well as the functioning of the heart, blood vessels, airways, and the organs involved in digestion and the urinary tract.

According to Noll Campbell, PharmD, the lead author of the study, 50 percent of older people take an anticholinergic drug daily. Many take a combination of both prescription and over-the-counter drugs. Anticholinergic effects include confusion, attention deficit, impaired concentration, memory problems, light-headedness, blurry vision, constipation, dry mouth, and loss of bladder control. Older people are more likely to experience anticholinergic effects because the body produces less acetylcholine with age. With aging, many cells in the body have fewer sites where acetylcholine can bond with them, which means the acetylcholine produced has less impact, and the effect of anticholinergic drugs is greater.

Here is a representative list of medications that may cause memory problems and other cognitive disturbances and anticholinergic effects. Patients should consult their doctor if they are experiencing memory or cognitive problems and are taking any medications.

* Antidepressants: amitriptyline: (Elavil); desipramine (Norpramin); imipramine (Tofranil); nortriptyline (Pamelor); venlafaxine-XR (Effexor-XR)

* Antihistamines/sleep aids: chlorpheniramine (Allerest, PediaCare), cyroheptadine (Periactin); diphenhydramine (Benadryl, Sominex, Unisom); promethazine (Phenergan)

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* Antihypertensives: nifedipine (Adalat, Procardia)

* Antipsychotics: chlorpromazine (Thorazine); haloperidol (Haldol); thioridazine (Mellaril)

* Antispasmodics: darifenacin (Enablex); fesoterodine (Toviaz); oxybutynin (Ditropan); tolterodine (Detrol)

* Bronchodilators: ipratropium bromide (Atrovent); tiotropium (Spiriva)

* Histamine-2 blockers: cimetidine: (Tagamet); famotidine (Pepcid); ranitidine (Zantac)

It’s important for older adults (indeed, anyone who takes drugs) to have current information on any medications they are taking. To help prevent memory and other cognitive problems associated with drug use, patients should consider the following tips:

* Make a written list of all the drugs they take both regularly and occasionally
* Carry a copy of the list and keep one at home on the refrigerator or other easily accessible spot
* Update the list whenever drugs change
* Share the list with their doctor(s) at each office visit or when drugs are changed
* Consult their doctor(s) before taking any new drugs or supplements

The extent of memory problems and other cognitive impairments caused by medication use in older adults has not been well recognized or appreciated, even though previous studies have noted that some often-used drugs have an effect on the brain. If doctors and patients are better informed about these negative effects, more judicious decisions about drug treatments can be made, memory and cognitive problems can be significantly reduced, and patients’ quality of life can improve.

Campbell N et al. Clinical Interventions in Aging 2009 May; 4: online
Han et al. Cumulative anticholinergic exposure is associated with poor memory and executive function in older men. J Am Geriat Soc 2008; 56(12): 2203.