Common Sleep and Allergy Medications Linked to Dementia, Alzheimer's

By Elizabeth Agnvall, January 29, 2015 08:00 AM

You may want to check your medicine cabinet after reading this.

A new study links long-term use of common medications — including over-the-counter drugs for insomnia and hay fever — to a higher risk of dementia, including Alzheimer’s disease. Medications in the study included antihistamines found in Benadryl, sleep aids found in Tylenol PM, and certain antidepressants and treatments for bladder control.

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Dementia risk in older adults starts to rise after three years of regular use of the medications, says study author Shelly Gray, professor of pharmacy at the University of Washington. The longer people took the drugs and the higher the dose, the higher the risk of dementia, although it’s important to note that short-term use was not linked to higher risks.

“We know that these medications may have an effect on memory, and we always assumed that these effects were reversible. We didn’t think these medications were changing the brain permanently. Our study does suggest a link between the highest use and increased dementia risk,” said Gray.

The researchers tracked 3,500 older adults for use of medications with an anticholinergic blocking effect on the nervous system. (The People's Pharmacy has a list of generic and brand-name anticholinergic medicines, including common side-effects.)

Medications that act on the brain this way are known to cause short-term problems with cognition and thinking — consider the pervasive “no driving or operating heavy machinery” warnings on the labels — but researchers with the University of Washington and Seattle’s Group Health Research Institute set out to see whether they have a long-term effect as well. They followed subjects for seven years, and used pharmacy records to track both prescription and over-the-counter medication use. The study was published Jan. 26 in JAMA Internal Medicine.

Because trouble sleeping is a common long-term dilemma for older adults, Gray recommended that they “think twice” before choosing o ver-the-counter sleeping pills and instead first try nondrug therapy for insomnia – such as avoiding sleep at least six hours before bedtime and waking up at the same time every day, even on weekends.

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Gray added that there are alternatives for many of these medications, including Celexa and Prozac for depression, and Claritin for allergies. Most important, she said, people should talk to their doctors about all the medications they are taking, including over-the-counter ones that don’t need a prescription, and make sure they are using the lowest dose for the least amount of time needed to alleviate symptoms. But she stressed that “no one should stop taking any therapy without consulting their health care provider.”

The top 20 drugs used by the study participants, in alphabetical order:

Amitriptyline (Elavil)
Atropine
Chlorpheniramine (Actifed, Allergy & Congestion Relief, Chlor-Trimeton, Codeprex, Efidac-24 Chlorpheniramine, etc.)
Desipramine (Norpramin)
Dicyclomine (Bentyl)
Diphenhydramine (Advil PM, Aleve PM, Bayer PM, Benadryl, Excedrin PM, Nytol, Simply Sleep, Sominex, Tylenol PM, Unisom, etc.)
Doxepin (Adapin, Silenor, Sinequan)
Hydroxyzine (Atarax, Vistaril)
Hyoscyamine (Anaspaz, Levbid, Levsin, Levsinex, NuLev)
Imipramine (Tofranil)
Meclizine (Antivert, Bonine)
Nortriptyline (Pamelor)
Olanzapine (Zyprexa)
Oxybutynin (Ditropan, Oxytrol)
Paroxetine (Brisdelle, Paxil)
Prochlorperazine (Compazine)
Promethazine (Phenergan)
Pseudoephedrine HCl/Triprolidine HCl (Aprodine)
Scopolamine (Transderm Scop)
Tolterodine (Detrol)