7 Medications That Can Affect Memory and Brain Function
Here’s the important detail first: the headline “7 medications that cause severe dementia and profound brain damage” is too strong. No responsible medical source supports the idea that these seven medicines simply cause severe dementia or permanent brain damage in everyone who takes them.
However, certain medications—especially in older adults—can cause confusion, sedation, delirium, memory problems, falls, and impaired thinking. Long-term exposure to some drugs, particularly those with strong anticholinergic effects, has also been associated with increased dementia risk. Importantly, an association does not prove that the medication directly causes dementia. National Institute on Aging+1
1. Diphenhydramine and Other First-Generation Antihistamines
Diphenhydramine is found in some allergy and nighttime cold/sleep products.
It has strong anticholinergic effects, meaning it interferes with acetylcholine, an important neurotransmitter involved in memory and cognition.
In older adults, these drugs can cause confusion, drowsiness, impaired thinking, constipation, urinary problems, and falls. The American Geriatrics Society recommends avoiding strong anticholinergic antihistamines in older adults when possible. PubMed Central (PMC)
Other examples include doxylamine, hydroxyzine, chlorpheniramine, and meclizine.
2. Amitriptyline and Certain Other Tricyclic Antidepressants
Amitriptyline and several other tricyclic antidepressants have significant anticholinergic activity.
They can cause drowsiness, confusion, dry mouth, blurred vision, constipation, and difficulty urinating, with older adults generally being more vulnerable to these effects.
The 2023 Beers Criteria lists several tricyclic antidepressants among medications with strong anticholinergic properties that should generally be avoided in older adults when safer alternatives exist. PubMed Central (PMC)
That doesn’t mean someone taking amitriptyline has dementia. It means the medication deserves careful review, particularly in an older person experiencing new cognitive symptoms.
3. Oxybutynin and Some Bladder Medications
Oxybutynin is used to treat overactive bladder and urinary urgency.
It has strong anticholinergic properties and can affect cognition, particularly in susceptible older adults.
The Beers Criteria specifically notes that oxybutynin has some of the strongest evidence for adverse cognitive effects among bladder antimuscarinics, although caution may be appropriate with this entire medication group. PubMed Central (PMC)
If an older person develops new confusion or memory problems after starting a bladder medication, it is worth asking a clinician or pharmacist whether the medication could be contributing.
4. Benzodiazepines
This class includes medications such as:
- Diazepam
- Lorazepam
- Alprazolam
- Clonazepam
- Temazepam
They are used for conditions including anxiety, seizures, and certain sleep problems.
In older adults, benzodiazepines can cause sedation, impaired coordination, confusion, memory problems, falls, and physical dependence. The current Beers Criteria recommends avoiding them in older adults in most circumstances, while recognizing specific situations in which they can be appropriate. PubMed Central (PMC)
The evidence regarding whether benzodiazepines themselves cause dementia is considerably less certain. Some studies have found associations while others have not. PubMed Central (PMC)
5. Z-Drugs Used for Sleep
Medications such as zolpidem, zaleplon, and eszopiclone are sometimes called “Z-drugs.”
Although they aren’t benzodiazepines chemically, they act on related brain pathways.
Older adults can be particularly susceptible to confusion, impaired coordination, falls, and other central nervous system effects. The Beers Criteria recommends avoiding these medications in older adults when possible. PubMed Central (PMC)
Regular use can also create dependence and doesn’t necessarily provide a good long-term solution for insomnia.
6. Certain Antipsychotic Medications
Antipsychotics can be essential for some serious psychiatric conditions, and they shouldn’t simply be discontinued because of a generalized warning.
But in older adults with dementia, antipsychotic medications have particularly important risks. The Beers Criteria notes an association with increased stroke risk and greater cognitive decline and mortality when these drugs are used for behavioral symptoms of dementia. PubMed Central (PMC)
For that reason, guidelines recommend non-drug approaches first when possible and careful medical supervision when an antipsychotic is genuinely necessary.
7. Some Opioid Pain Medications
Opioids can cause sleepiness, confusion, impaired alertness, and delirium, especially in older or medically vulnerable people.
The risk can become particularly concerning when opioids are combined with other sedating medications. For example, the Beers Criteria warns about combinations involving opioids and benzodiazepines because of the increased risk of serious adverse effects. PubMed Central (PMC)
That doesn’t mean people with severe pain should simply stop prescribed opioids. Pain treatment needs to be individualized.
Why Older Adults Are More Vulnerable
As people age, the body may process medications differently. Multiple medications are also common, meaning that several drugs with sedating or anticholinergic effects can add together.
The National Institute on Aging recommends reviewing medications when an older person develops cognitive problems and specifically highlights anticholinergics, antihistamines, narcotics, sedatives, and benzodiazepines as medications that may contribute to cognitive decline. National Institute on Aging
Recent NIH-supported research also found that potentially inappropriate central-nervous-system medications remain common among older adults with dementia, emphasizing the importance of medication review. National Institutes of Health
A Very Important Distinction: Confusion vs. Dementia
A medication can cause acute confusion or delirium without causing permanent dementia.
For example, an older person might become suddenly confused after starting a new medication, taking too much of a sedating medicine, or combining several drugs.
That’s different from Alzheimer’s disease, which is a progressive neurodegenerative condition.
In some cases, medication-related cognitive problems improve after the medication is reduced or discontinued under medical supervision.
Don’t Stop These Medications Suddenly
This is extremely important.
Some medications on this list—particularly benzodiazepines, certain antidepressants, opioids, and other centrally acting drugs—can cause withdrawal or other dangerous problems if stopped abruptly.
If you’re concerned about a medication, ask your doctor or pharmacist for a medication review. They can determine whether the dose should be changed, whether an alternative exists, or whether gradual tapering is necessary.
When a Medication Review Is Especially Important
Talk with a healthcare professional if someone taking these medications develops:
- New memory problems
- Increasing confusion
- Excessive daytime sleepiness
- Repeated falls
- New difficulty walking
- Hallucinations
- Major changes in alertness
- Problems managing previously familiar activities
And if confusion develops suddenly, seek medical evaluation rather than assuming it’s dementia. Sudden confusion can have many potentially treatable causes.
Final Takeaway
The safer conclusion isn’t “these seven drugs cause profound brain damage.”
It’s this:
Certain medications can significantly affect cognition—especially in older adults—and some classes have been associated with increased dementia risk or cognitive decline. Strong anticholinergics, benzodiazepines, Z-drugs, certain antipsychotics, and opioids deserve particular attention. National Institute on Aging+1
If you or a family member takes several medications and has noticed new memory or thinking problems, a professional medication review can be extremely valuable. Don’t discontinue prescription medicines on your own.
