Are My Medications Causing Me Memory Problems?

Most people assume that if they begin to have memory problems, it is either “natural” aging or bad luck. If a relative had Alzheimer’s disease, forgetfulness and dementia are blamed on genetic factors. But what if medications could be contributing to the epidemic of cognitive impairment that is affecting millions of people? Doctors are not always good about warning patients about medication-related cognitive difficulties.

This Neurologist Rejected Gabapentin-Induced Memory Problems:

Q. I was quite sharp until I was prescribed gabapentin and amitriptyline. Since then, my memory is garbage. I am currently being tested for dementia.

My neurologist said it couldn’t be from the meds, but I am not sure I believe him. These meds are ruining my life. Do you have any advice?

A. We fear your neurologist has not been doing his homework. The Beers list of “Potentially Inappropriate Medication Use in Older Adults” indicates drugs that can cause problems for senior citizens. The old-fashioned antidepressant amitriptyline can lead to confusion and memory problems because it interferes with the activity of the brain chemical acetylcholine. This anticholinergic action is associated with brain fog and other cognitive difficulties. Here is a link to our article:

Where Can I Find a List of Anticholinergic Drugs?

Gabapentin is a drug for epilepsy that is also prescribed for pain following a shingles attack. Many doctors prescribe it off label for neuropathy (nerve pain).

Research published in Frontiers in Pharmacology (Nov. 25, 2022) found a link between this medicine and cognitive decline:

“In conclusion, this study showed that among older adults with normal cognition, initiating gabapentin was significantly associated with clinically meaningful decline in cognitive and functional status and increased falls. Further studies are needed to examine the risk and benefit of prescribing gabapentin in older adults.”

Ask your neurologist to re-evaluate these prescriptions with an eye to gradual discontinuation. To help with this process, you may wish to review our free Guide to Drugs and Older People, which discusses the Beers list in greater detail. You will find it under the Health eGuides tab.

Another reader wants to know if a history of several anticholinergic drugs could cause irreversible brain damage.

Do Some Medicines Trigger Memory Problems?

Q. I’ve begun having some memory problems and they’ve made it difficult at times to function. Sometimes I forget how to use equipment I’ve used hundreds of times, or I have trouble with math that has always been easy for me.

I’ve taken many anticholinergic drugs over the years (antidepressants, tranquilizers, incontinence drugs, allergy drugs). I am just learning that these drugs could lead to cognitive difficulties.

There is a strong history of dementia in my mother’s family, and I have fears that some of the damage may be irreversible. Do you have any information that will help?

A. You need a thorough work-up to rule out obvious contributors to mild cognitive impairment such as thyroid problems or vitamin deficiency. In addition, the healthcare provider should review your current medications to minimize exposure to drugs that could affect your mental clarity.

Anticholinergic Motion Sickness Med Created Amnesia:

A concerned mother worried about her son’s memory problems:

Q. My son, now in his 50s, has always suffered from motion sickness. To travel to business meetings, he would take Dramamine but arrive sick and unable to function.

Recently, he has been taking scopolamine. Both times he has tried it, he has not been sick and attends the events without problems. However, the next day he does not remember anything about them. The entire day is lost.

I find this scary. Have you heard of others experiencing this? Will it lead to long term memory problems? He has tried lots of remedies before this, but nothing else has helped his motion sickness.

A. Scopolamine is a compound found in certain toxic plants such as belladonna, angels trumpet and Jimson weed. It helps prevent motion sickness, a property the Allies utilized in World War II while crossing the rough English Channel during the Invasion of Normandy. Today, doctors still prescribe Transderm Scop as a patch the patient wears behind their ear.

Scientists began experimenting with a combination of scopolamine and morphine at the turn of the 20th century. German doctors used it to induce anesthesia during surgery and childbirth. Morphine reduced the pain, and scopolamine ensured that the patient forgot any discomfort that did occur during labor and delivery.

Occasional use should not pose a serious problem. If he needs to remember what happened during his meetings, though, he may need a different strategy. If he has not yet used acupressure wrist bands, he might want to try them.

Here is a link to an article about how to avoid motion sickness. Readers share some of their favorite strategies.

Other Medications That Can Cause Memory Problems:

Both health professionals and patients may be shocked to learn that some of the most commonly prescribed drugs in the pharmacy can cause cognitive impairment or dementia. As this reader notes, anticholinergic drugs can include motion sickness medicine, allergy medications, antidepressants, anti-anxiety agents (benzodiazepines), and incontinence drugs. But that is only a partial list. Here is a quick overview:

Anticholinergic Drugs:

Researchers call the chemicals that make nerve cells function neurotransmitters. Acetylcholine (ACh) is one of those crucial neurochemicals. It is responsible for muscle contraction. Without adequate amounts of ACh, you wouldn’t be able to type on a keyboard, hold a pencil, breathe or blink. In particular, you need ACh for proper cognitive functioning and memory.

Medical students, pharmacy students, nursing students and physician assistants are all taught about anticholinergic drugs. Sadly, the training is often woefully inadequate.

Classic Anticholinergic Medications:

When health professionals learn about classic anticholinergic drugs, they start with deadly nightshade, i.e., belladonna. Chemical cousins, atropine, hyoscyamine and scopolamine were all derived from the plant Atropa belladonna. These drugs dry up secretions throughout the body by blocking the action of ACh on neurons. They also slow or diminish muscle contractions. As a consequence, they have multiple medical applications, but also some downsides.

Diarrea Drugs:

Atropine has been used to slow digestive tract motility and ease symptoms of diarrhea. You may recognize the brand name Lomotil which contains both atropine and diphenoxylate. Doctors often prescribe anticholinergic drugs to treat gastritis, colitis and diverticulitis.

Incontinence and Overactive Bladder:

Anticholinergic drugs like atropine and scopolamine can lead to urinary retention as a side effect. In other words, it becomes harder to empty the bladder when someone is taking an anticholinergic medication. Drug companies have turned this side effect into a “benefit” by developing a number of medications with anticholinergic activity and promoting them for overactive bladder. Such drugs include oxybutynin (Ditropan), tolterodine (Detrol) and fesoterodine (Toviaz).

Asthma, Bronchitis, COPD (chronic obstructive pulmonary disease):

Remember that we said anticholinergic drugs dry up secretions. As a result, they also ease some respiratory symptoms by opening constricted airways. Healers have used the smoke from plants containing atropine to help people with breathing problems for hundreds or thousands of years. Learn more about the old-timey uses of marijuana, stramonium and belladonna to treat asthma at this link. If you are looking for modern anticholinergic drugs for better breathing, check out ipratropium (Atrovent) and tiotropium (Spiriva).

Insomnia:

Another common side effect of anticholinergic drugs is drowsiness. People who take Benadryl (diphenhydramine) for allergies or Dramamine (dimenhydrinate) for motion sickness are familiar with this common complication. Drug companies have taken advantage of this adverse reaction by putting diphenhydramine in lots of OTC sleeping pills and PM pain relievers. Here is just a partial list of OTC drugs that may contain diphenhydramine:

Advil PM, Aleve PM, Bayer PM, Excedrin PM, Nytol, Simply Sleep, Sominex, Tylenol PM and Unisom.

Unexpected Sources of Anticholinergic Activity:

As mentioned above, most health professionals should know by now that drugs like atropine, scopolamine (for motion sickness) and diphenhydramine have strong anticholinergic activity. As a result, they can affect memory and cognitive function. What they may not realize is that there are a great many other drugs that also affect ACh action at nerve endings.

A number of antidepressants have significant anticholinergic activity (amitriptyline, desipramine, doxepin, imipramine, nortriptyline, paroxetine, etc). Moreover, antihistamines such as chlorpheniramine are found in dozens of allergy medications.

Antipsychotic drugs such as chlorpromazine, prochlorperazine and olanzapine (Zyprexa) also have anticholinergic activity. Drugs for dizziness like meclizine (Antivert) are included in this category along with codeine, cimetidine (Tagamet) and the diuretic furosemide (Lasix). One critical word of caution: people with heart problems should NEVER stop Lasix on their own because it can lead to a life-threatening buildup of fluid.

The Anticholinergic Body Burden:

You may not be able to avoid all such drugs, but the more anticholinergic medicines someone is taking, the greater the risk of memory problems. Moreover, the longer such drugs are taken, the greater the risk of memory problems.

We are frequently asked if we have prepared a list of anticholinergic drugs. The answer is yes! Here is a link to a fairly extensive list. Even your physician may be unaware of all these medications. It is not so much any single drug that is the problem, though. It is the total number of anticholinergics and the length of time someone takes them. Given this information, you may be tempted to stop some of your drugs right now. Remember, though, no one should ever stop any medicine without checking with the prescriber!

Are Anticholinergic Drug Effects Temporary or…?

Scientists do not know whether the anticholinergic effect can be reversed completely. A study published in the journal Cerebral CORTEX (online, June 16, 2016) gives us pause. The researchers studied the impact of “cholinergic dysfunction” on the brains of mice. By blocking the action of ACh in an effort to mimic the impact of anticholinergic drugs, the researchers wanted to see what happened in their rodent model. They found that without adequate ACh, brain cells died and that learning and memory were affected.

A primary author of the study was quoted:

“We demonstrated that in order to keep neurons healthy you need acetylcholine…So if acetylcholine actions are suppressed, brain cells respond by drastically changing their messenger RNAs and when they age, they show signs of pathology that have many of the hallmarks of Alzheimer’s disease.”

Learn More:

You can listen to a short interview with Dr. Shelly Gray as she describes her research on this topic. She and her colleagues published it in JAMA Internal Medicine. Here is a link to the free streaming audio of the show or the MP3.

You need to make sure your physician knows which of your medications has anticholinergic activity so you can lower the anticholinergic burden that is being placed on your brain.

To help you with that process, here is a link to our Guide to Drugs and Older People with a list of anticholinergic drugs and other medications that are considered inappropriate for older people. You may want to take it with you to your next doctor’s appointment.

Final Words:

Have you ever experience memory problems you attributed to a medication? Please share your story in the comment section below. If you suspect that a friend or family member is suffering from drug-induced cognitive dysfunction you may want to send them a link to this article. You can do that by scrolling to the top of the page and clicking on the email icon or one of the social media links. No one should ever stop a medication without discussing it with the prescribing physician.