Want to keep your brain — or the brain of someone you love — as healthy as possible?
Then it’s essential to know which commonly used medications affect brain function.
In this article, I’ll go into details regarding a type of medication that I wish all older adults knew about: anticholinergic drugs.
How Anticholinergics Affect the Aging Brain and Body
Anticholinergics are drugs that block acetylcholine, a key neurotransmitter in the body. This leads to lower brain function, which people often experience as drowsiness.
Sometimes that sedation is why people take the drugs, and a little sleepiness might sound benign. But when the brain is older, or otherwise vulnerable, these drugs can be problematic.
In fact, these literally have the opposite effect of the drugs often used to treat Alzheimer’s and other dementias. Donepezil, rivastigmine, and galantamine (brand names Aricept, Exelon, and Razadyne), for example, are designed to increase acetylcholine by blocking the brain enzyme that breaks it down.
Research has linked anticholinergic drugs to increased risk of Alzheimer’s disease, and also to hospitalizations in older adults. And the American Geriatrics Society has warned about them for years; anticholinergics are definitely on the Beer’s List of medications older adults should avoid or use with caution.
Acetylcholine is a neurotransmitter used in many other parts of the body, including the eyes, mouth, bowels, and bladder. So anticholinergic drugs commonly cause side-effects such as dry eyes, dry mouth, and constipation.
These drugs are in everything from allergy medicines to muscle relaxants to painkillers. They are in many over-the-counter (OTC) medications, and they are often prescribed for a variety of common health complaints.
7 Common Types of Medication that are Anticholinergic
Here are seven common types of anticholinergic medication that older adults should avoid, or use with caution:
1. Sedating antihistamines. The prime example is diphenhydramine (brand name Benadryl), which is available over-the-counter and has strong anticholinergic activity. Non-sedating antihistamines, such as loratadine (brand name Claritin) are less anticholinergic and are safer for the brain.
2. PM versions of over-the-counter (OTC) painkillers. Most OTC painkillers, such as acetaminophen and ibuprofen (brand names Tylenol and Motrin, respectively) come in a “PM” or night-time formulation, which means a mild sedative — usually an antihistamine — has been mixed in. Ditto for night-time cold and cough medications such as Nyquil.
3. Medications for overactive bladder. These include bladder relaxants such as oxybutynin and tolterodine (brand names Ditropan and Detrol, respectively).
4. Medications for vertigo or motion sickness. Meclizine (brand name Antivert) is often prescribed to treat benign positional vertigo. It’s also used to treat motion sickness.
5. Medications for itching. These include the strong antihistamines hydroxyzine (brand name Vistaril) and diphendyramine (brand name Benadryl), which are often prescribed for itching or hives.
6. Medications for nerve pain. An older class of antidepressant known as “tricyclics” isn’t used for depression that much any longer, but these drugs are occasionally still used to treat pain from neuropathy. Commonly-used tricyclics include amitriptyline and nortriptyline.
7. Muscle relaxants. These include drugs such as cyclobenzaprine (brand name Flexeril) and they are often prescribed for back or neck pain.
Also anticholinergic is the SSRI-type anti-depression/anxiety drug paroxetine (brand name Paxil), which is why geriatricians almost never prescribe this particular SSRI. However, other SSRIs, including escitalopram, citalopram, and sertraline (brand names Lexapro, Celexa, and Zoloft, respectively) are not anticholinergic, which is why SSRIs aren’t on the list above.
Many more medications have strong anticholinergic effects, but they tend to be prescribed less often. Ask your doctor or pharmacist if you want help spotting all anticholinergics you might be taking.
Who Should Avoid Anticholinergics?
You should especially avoid or minimize anticholinergics if you:
- Are worried about your memory,
- Have been diagnosed with mild cognitive impairment or dementia such as Alzheimer’s disease, or
- Want to reduce your risk of developing Alzheimer’s.
How to Reduce Brain Risk Due to Anticholinergics
For a longer list of anticholinergics that your older relative might be taking, I recommend this list, which specifies whether the drugs have “definite” anticholinergic activity versus “possible.” You’ll want to focus on identifying and minimizing drugs in the “definite” category.
Or, you can look up any of your medications using this handy “anticholinergic burden scale” calculator.
To date, several research studies have reported a concerning association between cumulative lifetime dosing of anticholinergics and dementia risk. (See Anticholinergic Drug Exposure and the Risk of Dementia and here’s one specific for bladder drugs.) Other recent scholarly papers reviewing how anticholinergic medications affect older adults can be found here, here, and here.
For more help identifying and reducing anticholinergic drugs, you can also ask your doctor or pharmacist.
If you find that you or your older relative is taking an anticholinergic drug, don’t panic. But do plan on reviewing the benefits and risks with the doctor soon. You may be able to reduce the dosage of these risky drugs, switch to a safer medication, or try a non-drug treatment instead.
For more on medications that affect brain function, see 4 Types of Medication to Avoid if You’re Worried About Memory.
I also provide more on reducing risky medications here: Deprescribing: How to Be on Less Medication for Healthier Aging.
This article was first published in 2015, and was last updated by Dr. K in April 2022.