Antidepressants, Sleep Aids, and Allergy Drugs Linked to Alzheimer’s Disease

For many years, consumers have taken Benadryl as a sleep aid, assuming that it is a safe and non-habit forming solution for occasional insomnia. A recent study, however, led by Dr. Shelly Gray of the University of Washington School of Pharmacy and published in JAMA Internal Medicine suggests that several over-the-counter drugs–Nytol, Benadryl, and Piriton–may raise one’s chances of developing Alzheimer’s disease and other forms of dementia. Gray adds that other potentially risky drugs in this class, all of which are considered to be anticholinergic, include some bladder control drugs, antidepressants, sleep aids, and allergy medications.

The Guardian notes that anticholinergic drugs work by “block[ing] a nervous system chemical transmitted called acetylcholine, which can lead to side effects including drowsiness, blurred vision, and poor memory. People with Alzheimer’s disease are known to lack acetylcholine.” Similarly, results from animal testing suggest that these drugs increase the level of beta-amyloid protein in the brain, which is a telltale sign of Alzheimer’s disease in humans.

MarketWatch reports that a relationship between anticholinergic drugs and cognitive impairment in elderly people popped up in some medical literature last year, but this is the first article to suggest higher doses of such medications are linked with increased risk of dementia. The sample in this study included 3,434 men and women over age 65, 637 of whom developed Alzheimer’s and 160 of whom developed other forms of dementia. Those who took the largest doses of these drugs faced a 54 percent greater risk of dementia and a 63 percent greater risk of Alzheimer’s than those who took none.

Conclusions we may draw from this publication are limited, however, and researchers must conduct even more trials and studies to establish facts more concretely. One Alzheimer’s scholar notes, “[I]t is still unclear whether the effects seen are a result of long-term use or several episodes of short-term use.”

Authors of the paper stress the importance of not discontinuing a course of medication based on one study, urging patients to discuss the matter with their doctors and pharmacists before making any changes. The lead researcher Shelly Gray also mentions that non-anticholinergic substitutes for many drugs exit, pointing to selective serotonin reuptake inhibitor antidepressants like Prozac and antihistamines like Claritin.

Gray adds that it is important to get this information to the public, especially among older individuals, because there are so many alternative treatments available and because dementia and dementia-related ailments are so devastating to both health and independence.

On a slightly different note, the risks associated with anticholinergic drugs represent another possible oversight of the FDA’s post-market inspection system. As we have explained in the past, the FDA has proven that it lacks the resources or the commitment necessary to monitor drugs’ long-term side effects. Generally, after the agency approves a drug, its manufacturer becomes responsible for reporting health and safety risks associated with it. As we have seen time and time again, it is not in a company’s best interest to report its drugs as dangerous, and this is why consumers should demand stricter post-market oversight from government regulators.