Many older adults take numerous medications. This practice, called polypharmacy, has been linked to lower memory function. It is becoming apparent that some of those commonly prescribed drugs may contribute to memory difficulties. Some affect short-term memory, which refers to anything that happened within the last 30 seconds. Examples of this are forgetting what you went into a room to get or what you had in mind to add to your grocery list, which you forget by the time you find your pen! Long-term memory is defined as anything that occurred more than 30 seconds ago.

If a medicine is interfering with short-term memory, the effects are mostly seen in the person’s ability to focus and process information. Generally, the effects disappear once the person stops taking that medication.

There is a greater concern if a person is taking several mediations concurrently, or if they are being taken at high doses and/or for a long period of time. In these cases, the drugs can interfere with long-term memory because they affect neurotransmitters, the chemical messengers that aid in thinking and memory.

The remainder of this blog describes some drugs that that may cause memory loss. However, no one should stop or reduce the dosage of any medications they are on without first speaking with their health care professional.

1. Antianxiety drugs (benzodiazepines) dampen activity in key parts of the brain, including those involved in transferring events from short-term to long-term memory. This is why they are used in anesthesia. It takes older adults longer than younger people to flush these out of their bodies, so the buildup can put older adults at higher risk for delirium, falls, and car accidents. They can also be addicting.
2. Tricyclic antidepressants are older drugs used primarily for depression and anxiety, and can block the action of serotonin and other chemical messengers in the brain, which can cause memory glitches. Newer medications for depression, such as Prozac and Zoloft do not have the same anticholinergic effects and usually do not interfere with cognitive functions.
3. Antiseizure drugs include Tegretol and Lamictal, among others. By depressing signaling in the central nervous system they can cause memory loss. However, because they are sedating, it’s possible that what appears to be cognitive decline is actually the effects of the sedation. Physicians may be able to prescribe other medications which have less of an impact on memory.
4. Narcotic painkillers (opioids) are often used to relieve pain from injuries or surgery. These include Fentanyl, Vicodin, and Oxycontin, which work by stemming the flow of pain signals within the central nervous system and by blunting one’s emotional reaction to pain. If used for extended periods, these can interfere with both short- and long-term memory.
5. Sleeping aids which are used to treat insomnia and other sleep problems include Lunestra and Ambien, among others. These drugs can cause amnesia and sometimes trigger dangerous or strange behaviors. Options for getting more restorative sleep might include melatonin or magnesium, and especially the use of cognitive-behavioral therapy for insomnia (CBT-I).
6. Incontinence drugs (anticholinergics) are often prescribed to relieve symptoms of overactive bladder and reduce episodes of urge incontinence. They can cause difficulties with long-term memory and have been associated with an increased risk of dementia, since they block the action of acetylcholine, a neurotransmitter that plays a major role in voluntary muscle movement all over your body and in brain nerve cells involved in memory, thinking and learning.
7. Antihistamines (first generation) are often used to prevent or relieve allergy or cold symptoms. Some are used to prevent motion sickness, nausea, vomiting and dizziness, or to treat insomnia. They inhibit the action of acetylcholine which, as stated above, can affect activity in the memory and learning centers of the brain. Some physicians are now using Claritin and Zyrtec which have fewer memory and cognitive side effects.

Statins, used to control cholesterol, have more recently been found not to show any increase in memory problems or relationship to other cognitive impairments. And their effectiveness at preventing strokes may ultimately result in protection against cognitive decline.

No one should change their medication ritual based on information in this article. However, if you are experiencing memory or other cognitive difficulties, it might be advisable to ask your  physician if you are on the lowest effective dose to manage your condition or if it might be possible to switch to a different class of medication which might have fewer negative side effects for you.