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People’s Pharmacy: Medicines can throw a monkey wrench in memory

Older adults often worry about their memory and their mental sharpness. When people have trouble recalling their Social Security number or a familiar person’s name at church, they may become frightened that dementia is setting in.

Alzheimer’s disease is a real risk associated with aging. But common medications often can contribute to confusion or forgetfulness.

Diphenhydramine (DPH) used to be found primarily in a highly sedating antihistamine called Benadryl. At one time, doctors prescribed it for allergy symptoms and warned their patients that it might make them drowsy. It has long been available over the counter.

If DPH were only being used as an antihistamine, it probably wouldn’t pose much of a risk for older people. But this compound is now found in many other medications, particularly in some that are marketed to the elderly. These are nighttime pain relievers such as Advil PM, Aleve PM and Tylenol PM.

The “PM” designation that suggests the drug will cause drowsiness nearly always indicates the presence of DPH. It also is found in a number of OTC sleep aids, such as Sominex, Unisom and ZzzQuil.

Diphenhydramine belongs to a category of medications called anticholinergics. These are drugs that interfere with the activity of the essential brain neurotransmitter acetylcholine.

Drugs with anticholinergic action can cause a number of unpleasant side effects, including dry mouth, constipation, blurred vision, drowsiness, difficult urination and decreased sweating. They also can cause confusion, memory problems and hallucinations.

The number of medicines that have anticholinergic activity is surprisingly high and often goes unrecognized. The most obvious examples include scopolamine, found in the motion-sickness medicine Transderm Scop. It also is found in some medicines for irritable bowel syndrome, such as Donnatal.

Other medicines that older people may take more frequently include drugs for urinary incontinence, euphemistically termed “overactive bladder.” These medications include oxybutynin (Ditropan, Oxytrol) and tolterodine (Detrol). Researchers have reported that oxybutynin has a high incidence of side effects, especially cognitive impairment in older people (International Journal of Clinical Practice, September 2014).

We received this message from a concerned wife: “My 73-year-old husband is taking Detrol LA. I have noticed that he is often confused about what day it is, does not remember conversations and can no longer keep the checkbook balanced.”

Combining anticholinergic medicines can lead to symptoms of dementia. We have a detailed list of anticholinergic drugs at PeoplesPharmacy.com. Consult it to protect yourself and loved ones.

Joe Graedon is a pharmacologist. Teresa Graedon holds a doctorate in medical anthropology and is a nutrition expert. Their syndicated radio show can be heard on public radio. In their column, Joe and Teresa Graedon answer letters from readers. Write to them via their website: PeoplesPharmacy.com.