(Note to readers: AgeWise Colorado acknowledges AARP as the major source of information in this article. AARP is an AgeWise Colorado Provider. See https://agewisecolorado.org/provider/aarp-colorado/ to learn more.)

For a long time, doctors dismissed forgetfulness, brain fog, and mental confusion as normal parts of aging. But scientists now know that memory loss as you get older is by no means inevitable. In fact, routine memory, skills, and knowledge may even improve with age, according to the Centers for Disease Control and Prevention (CDC).

Many things can impair memory. Among the causes are alcohol and drug abuse, heavy cigarette smoking, head injuries, stroke, sleep deprivation, severe stress, vitamin B12 deficiency, and illnesses such as Alzheimer’s disease and depression. What many people do not know is that a number of commonly prescribed drugs also can interfere with memory. This article looks at seven types of drugs that may cause memory loss and describes alternative treatment options.

Important Note: Nothing in this article should be considered medical advice. Although various drugs and certain alternatives will be discussed, your own decisions should always be made in consultation with your personal physician and/or other trusted professional healthcare advisors.

Short- vs. Long-Term Memory

There are two key types of memory: short- and long-term. Short-term memory, also known as working memory, refers to anything that happened within the last 30 seconds — like forgetting what you meant to add to your grocery list after picking up your pen or misplacing your eyeglasses. Long-term memory involves anything beyond this brief window. Whether it’s a recent event or a childhood memory, forgetting something after more than 30 seconds is considered long-term memory loss.

Drugs that affect short-term memory can interfere with a person’s ability to focus and process information. These medications disrupt so-called messenger pathways in the brain, changing the short-term memory processing. Once a person stops taking the medications, however, short-term memory improves.

Medications that can impact long-term memory interfere with neurotransmitters in the brain. These are the body’s chemical messengers that help you to think, move, breathe, and function generally, and when they don’t work like they should, a number of problems can occur, including issues with thinking and memory.

The biggest concern with medications that mess with neurotransmitter activity is when several are used concurrently, when they are used at high doses, and when they are used for long periods of time. This is according to Joshua Niznik, an assistant professor of medicine at the University of North Carolina School of Medicine.

Certain medications can affect both short- and long-term memory, while others may affect only one. Drugs that may cause memory loss include the following:

  • Antianxiety drugs
  • Antiseizure drugs
  • Tricyclic antidepressants (older class)
  • Narcotic painkillers
  • Sleeping aids
  • Incontinence drugs
  • Antihistamines (first generation)

We will discuss these one-by-one.

Antianxiety Drugs (benzodiazepines) & Memory Loss

Why they are prescribed: Benzodiazepines are used to treat a variety of anxiety disorders, agitation, seizures, delirium, and muscle spasms. Because benzodiazepines have a sedative effect, they are sometimes used to treat insomnia and the anxiety that can accompany depression.

Examples: Alprazolam (Xanax), chlordiazepoxide, clonazepam (Klonopin), diazepam (Valium), flurazepam, lorazepam (Ativan), midazolam, quazepam (Doral), temazepam (Restoril), and triazolam (Halcion).

How they can affect memory: Benzodiazepines dampen activity in key parts of the brain, including those involved in the transfer of events from short-term to long-term memory. In fact, they’re used in anesthesia for this very reason.

Alternatives: Benzodiazepines should be prescribed only rarely in older adults, and then only for short periods of time. It takes older people much longer than younger people to flush these drugs out of their bodies, and the ensuing buildup puts older adults at higher risk for not just memory loss but delirium, falls, fractures, and motor vehicle accidents. Another drawback: They’re addicting, says D.P. Devanand, M.D., professor of psychiatry and neurology at Columbia University Medical Center.

What you can do: Talk with your doctor or other healthcare professional about treating your condition with other types of drugs or nondrug treatments. If you are taking these medications for insomnia, for instance, the first line of treatment is cognitive behavioral therapy for insomnia, or CBT-I. (See our AgeWise Colorado article on CBT-I at https://agewisecolorado.org/blog/drug-free-therapy-for-insomnia-may-be-best-choice-for-coloradans/.) Be sure to consult your healthcare professional before stopping or reducing the dosage of any benzodiazepine. Sudden withdrawal can trigger serious side effects, so a health professional should always monitor the process.

Antiseizure Drugs (anticonvulsants) & Memory

Why they are prescribed: Long used to treat seizures, these medications can also be prescribed for nerve pain, bipolar disorder, mood disorders, and mania.

Examples: Carbamazepine (Tegretol), gabapentin (Neurontin), lamotrigine (Lamictal), levetiracetam (Keppra), oxcarbazepine (Trileptal), pregabalin (Lyrica), rufinamide (Banzel), topiramate (Topamax), valproic acid (Depakote), phenobarbital (Luminal), primidone (Mysoline), and zonisamide (Zonegran).

How they can affect memory: Anticonvulsants are believed to limit seizures by dampening the flow of signals within the central nervous system (CNS). Drugs that depress signaling in the CNS can cause memory loss. One thing to note: These medications can be sedating, and sometimes it’s hard to separate what is a true cognitive decline from simple sedation.

Alternatives: Many patients with seizures do well on phenytoin (Dilantin), which, at lower doses, has less of an impact on memory. Patients with chronic nerve pain find that venlafaxine (Effexor) — which also spares memory — alleviates their pain.

What you can do: Talk with your doctor or other healthcare professional about treating your condition with other types of drugs or nondrug treatments. Always consult your healthcare professional before stopping or reducing the dosage of any drug. Sudden withdrawal can trigger serious side effects.

Tricyclic Antidepressants & Memory

Why they are prescribed: This older class of antidepressant drugs is prescribed less often these days, but some people still use tricyclics for depression, anxiety disorders, obsessive-compulsive disorder, and nerve-related pain.

Examples: Amitriptyline (Elavil), clomipramine (Anafranil), desipramine (Norpramin), doxepin (Silenor), imipramine (Tofranil), nortriptyline (Pamelor), protriptyline (Vivactil) and trimipramine (Surmontil).

How they can affect memory: Tricyclic antidepressants block the action of serotonin, norepinephrine, and other chemical messengers in the brain, which can lead to a number of side effects, including lapses in memory.

Alternatives: Newer antidepressants like fluoxetine (Prozac), sertraline (Zoloft), and other selective serotonin reuptake inhibitors (SSRIs) don’t have the same anticholinergic effects as tricyclic antidepressants and therefore don’t interfere with cognition.

What you can do: Talk with your healthcare provider about which drugs might be best for you or whether nondrug therapies might work just as well or better for you than a drug.

Narcotic Painkillers (opioids) & Memory

Why they are prescribed: These medications are sometimes used to relieve moderate to severe pain from surgery or injuries. In some instances, they can also be used to treat chronic pain.

Examples: Fentanyl (available as a patch), hydrocodone (Vicodin), hydromorphone (Dilaudid, Exalgo), morphine, and oxycodone (Oxycontin). These drugs come in many different forms, including tablets, solutions for injection, transdermal patches, and suppositories.

How they can affect memory: These drugs work by stemming the flow of pain signals within the central nervous system and by blunting one’s emotional reaction to pain. Both these actions are mediated by chemical messengers that are also involved in many aspects of cognition, so use of these drugs can interfere with long- and short-term memory, especially when used for extended periods of time. Researchers have also found a link between opioid use and dementia in older adults.

Alternatives: In patients under the age of 50 years, nonsteroidal anti-inflammatory drugs (NSAIDs) are the frontline therapy for pain. Unfortunately, NSAID therapy is less appropriate for older patients, who have a much higher risk of gastrointestinal bleeding. Research shows the risk goes up with the dosage and duration of treatment.

What you can do: You might consider acetaminophen (Tylenol) as another option. But again, it’s important to consult your doctor about risks, side effects, and drug interactions for all medications.

Sleeping Aids (nonbenzodiazepine sedative-hypnotics) & Memory

Why they are prescribed: Sometimes called the “Z” drugs, these medications can be used to treat insomnia and other sleep problems. They also are prescribed for mild anxiety.

Examples: Eszopiclone (Lunesta), zaleplon (Sonata), and zolpidem (Ambien).

How they can affect memory: Although these are molecularly distinct from benzodiazepines (see above), they act on many of the same brain pathways and chemical messengers, producing similar side effects and problems with addiction and withdrawal. The “Z” drugs also can cause amnesia and sometimes trigger dangerous or strange behaviors, such as cooking a meal or driving a car with no recollection of the event upon awakening.

Alternatives:  Melatonin can help to reestablish healthy sleep patterns. And cognitive behavioral therapy for insomnia (CBT-I) is the first-line treatment for the sleep disorder. (See more on CBT-I under antianxiety drugs above.)

What you can do: Talk with your healthcare professional about options. Before stopping or reducing the dosage of these sleeping aids, be sure to consult your healthcare provider. Sudden withdrawal can cause serious side effects.

Incontinence Drugs (anticholinergics) & Memory

Why they are prescribed: These medications are used to relieve symptoms of overactive bladder and reduce episodes of urge incontinence, an urge to urinate so sudden and strong that you often can’t get to a bathroom in time.

Examples: Darifenacin (Enablex), oxybutynin (Ditropan XL), solifenacin (Vesicare), tolterodine (Detrol), and trospium (Sanctura). Another oxybutynin product, Oxytrol for Women, is sold over the counter.

How they can affect memory: Patients who take anticholinergics can have complications with their long-term memory. These medications have been associated with an increased risk of dementia, and that heightened risk can persist even after the medication has been discontinued. That’s because these drugs block the action of acetylcholine, a neurotransmitter that mediates all sorts of functions in the body. In the bladder, anticholinergics prevent involuntary contractions of the muscles that control urine flow. In the brain, they inhibit activity in the memory and learning centers. The risk of memory loss is heightened when the drugs are taken for more than a short time or used with other anticholinergic drugs. Older adults are particularly vulnerable to the other adverse effects of anticholinergic drugs, including constipation (which, in turn, can cause urinary incontinence), blurred vision, dizziness, anxiety, depression, and hallucinations.

Alternatives: As a first step, it’s important to make sure that you have been properly diagnosed. Check with your doctor or other health professional to see if your urinary incontinence symptoms might stem from another condition (such as a bladder infection or another form of incontinence) or a medication (such as a blood pressure drug, diuretic, or muscle relaxant). Some urologists are treating overactive bladder with Botox injections to help the muscle relax.

What you can do: If organic causes have been ruled out, you could try some simple lifestyle changes, such as cutting back on caffeinated and alcoholic beverages, drinking less before bedtime, and doing exercises to strengthen pelvic floor muscles that help control urination (e.g., Kegel exercises). Some clinicians also point out that protective undergarments have seen great improvements over time. Here again, the same cautions apply about consulting with your professional healthcare provider(s) before changing any prescribed medications.

Antihistamines (first generation) & Memory

Why they are prescribed: These medications are used to relieve or prevent allergy symptoms or symptoms of the common cold. Some antihistamines are also used to prevent motion sickness, nausea, vomiting and dizziness, and to treat anxiety or insomnia.

Examples: Brompheniramine (Dimetane), chlorpheniramine (Chlor-Trimeton), clemastine (Tavist), diphenhydramine (Benadryl), promethazine (Phenergan), and hydroxyzine (Vistaril).

How they can affect memory: These medications (prescription and over-the-counter) inhibit the action of acetylcholine, a chemical messenger that mediates a wide range of functions in the body. In the brain, they inhibit activity in the memory and learning centers.

Alternatives: Newer-generation antihistamines such as loratadine (Claritin) and cetirizine (Zyrtec) are better tolerated by older patients and do not present the same risks to memory and cognition.

What you can do: Consult with your healthcare provider(s) about your options.

Other Medications Worth Noting

Beta-Blockers. While there is no evidence that beta-blockers — prescribed for heart failure, angina, certain heart rhythm disorders, and sometimes high blood pressure — contribute to long-term cognitive decline or dementia, they can make some people feel “fatigued” or “foggy.” If you experience these effects, don’t stop taking your medication. Talk to your doctor about switching to a different beta-blocker with a slightly different chemical composition.

Corticosteroids. These anti-inflammatory drugs, which are used to treat rheumatoid arthritis, lupus, and other conditions, can cause confusion and memory loss in patients on high doses. They can also trigger depression.

Heartburn Meds. Some recent studies have found a link between medications commonly used to treat gastroesophageal reflux disease (GERD), heartburn, and peptic ulcers with an increased risk of dementia. If you take an over-the-counter (OTC) proton-pump inhibitor, it’s important to use the medication in moderation and for short amounts of time. The typical recommendation is not to use any OTC med of this kind for more than two weeks at a time.

Cannabinoids. Access to cannabis and use of the drug have grown in recent years and is common in Colorado. Mounting research shows that cannabis may have an effect on cognition. A study published in The American Journal of Psychiatry in March 2022 followed approximately 1,000 individuals and found that long-term cannabis users showed cognitive deficits, as well as memory and attention problems.

Statins. Statins at one time were thought to be a memory-related concern, but not so anymore for these cholesterol-lowering drugs. Large studies in hundreds of thousands of individuals monitored very carefully did not show any increase in memory problems or anything else related to brain function. A 2018 scientific statement from the American Heart Association says there is “no convincing evidence for a causal relationship” between statins and cognitive dysfunction. On the contrary, the data suggests that statins may be protective against cognitive decline, since they are effective at preventing strokes. Still, side effects of any drug can vary from one individual to another. If you have concerns about statins, talk to your doctor.

Medications and Sundowning

Although sundowning syndrome — a state of confusion or agitation that occurs late in the afternoon and stretches into evening — is typically linked to Alzheimer’s disease, it can occur with any type of dementia. And medications like anticholinergics, tricyclic antidepressants, antihistamines, and anti-Parkinson’s drugs can trigger or worsen its symptoms. Other substances — alcohol and nicotine, for example — can also cause sundowning. If this presents a concern, consult with your doctor.

Other Things to Know, and Possibly Do

If you are worried that medications could be messing with your memory, or the memory of a loved one, start by asking others closest to you if they’ve noticed any issues. And of course never hesitate to talk to your doctor(s).

Also bear in mind that the number of drugs you’re taking could be affecting your memory as well. Taking multiple medications — a practice known as polypharmacy — has been linked to lower memory function in older adults, as well as an increased risk for delirium. One study found that 42 percent of older adults take five or more prescription medications. If you’re concerned about the number of pills you’ve been prescribed to take, ask your doctor if every single one of them is still necessary or if there are any you can stop taking.

This process, known as “deprescribing,” involves reducing the dose, gradually tapering off, or eliminating drugs that may contribute to memory loss. Another approach is switching to a different class of medication with fewer potential complications. Ask your healthcare provider if you’re on the lowest effective dose to manage your condition. Higher doses of certain medications can increase the risk of memory loss; it’s essential to find the right balance.

It bears repeating: If you want to lower the dosage of a drug or stop taking a medication, be sure to do so only under the supervision of your doctor.