As we get older, taking several prescription and over-the-counter medicines at the same time becomes more common. Some medications can cause temporary confusion, drowsiness, or memory problems, while research has also found associations between long-term exposure to certain medicines and a higher risk of dementia.
That does not mean these medicines are “dementia drugs” or that everyone who takes them will develop dementia. Many are useful and appropriate treatments when prescribed for the right person.
One group that has received particular attention is anticholinergic medication. These medicines block the action of acetylcholine, a chemical messenger involved in memory, learning, and other functions. Studies have found associations between higher or prolonged anticholinergic exposure and cognitive decline or dementia, although observational studies cannot establish that the medicines themselves are the direct cause.
Here are eight categories worth discussing with a doctor or pharmacist if you’re concerned about memory.
1. Certain Antidepressants
Some older antidepressants, particularly certain tricyclic antidepressants, have significant anticholinergic effects.
Examples include:
- Amitriptyline
- Dosulepin
- Some other tricyclic antidepressants
These medicines can be very effective for certain conditions, but long-term use should be periodically reviewed, particularly in older adults.
Importantly, not all antidepressants have the same anticholinergic effects.
2. Some Bladder-Control Medicines
Certain medications used to treat overactive bladder and urinary incontinence have anticholinergic properties.
Examples include:
- Oxybutynin
- Tolterodine
- Solifenacin
Long-term cognitive effects of these medicines remain an area of medical research, and evidence varies between individual drugs. NICE notes that the long-term effect of anticholinergic medicines used for overactive bladder on cognitive function remains uncertain.
That doesn’t mean someone should suddenly stop taking their bladder medication.
3. Certain Parkinson’s Medicines
Some older medicines used to treat Parkinson’s symptoms have anticholinergic effects.
Procyclidine, for example, has been included among medications associated with increased anticholinergic burden in older adults.
Because Parkinson’s disease itself can affect cognition, medication decisions need to be individualized rather than based on one risk factor.
4. Some Older Antihistamines
Certain first-generation antihistamines can have anticholinergic effects and may cause drowsiness or confusion, particularly in older adults.
However, it is important not to put every allergy medicine into the same category. Research has not shown the same dementia association for all antihistamines, and different medicines have very different properties.
If an older adult becomes unusually sleepy or confused after starting an allergy medicine, a pharmacist or doctor can review the medication.
5. Certain Medicines Used for Nausea or Motion Sickness
Some medications used for motion sickness or nausea have anticholinergic properties.
They can sometimes cause temporary effects such as:
- Drowsiness
- Dry mouth
- Blurred vision
- Confusion
These effects can be particularly noticeable in older adults.
Importantly, evidence about these medications and long-term dementia risk is not as straightforward as viral headlines often suggest. Earlier research raised concerns about several anticholinergic categories, while later analysis has found differences between individual drug groups.
6. Some Medicines for Long-Term Pain
Certain medications used for chronic pain can affect alertness, concentration, or cognition.
A person who becomes unusually sleepy, confused, or mentally slowed after starting or increasing a medication should tell their healthcare professional.
This does not automatically mean the medication is causing dementia. Medication-related confusion can be temporary and potentially reversible.
7. Medicines With a High Overall Anticholinergic Burden
Sometimes the concern isn’t one particular medication.
A person may take several medicines that each have mild anticholinergic effects. Together, their anticholinergic burden can become significant.
NICE notes evidence linking anticholinergic medicines with poorer cognitive performance and greater cognitive decline in older people.
This is why medication reviews are especially important for older adults taking multiple prescriptions.
8. Multiple Medications Taken Together
Older adults often take several medicines for different conditions.
Even when each medication is appropriate individually, combinations can contribute to:
- Drowsiness
- Dizziness
- Confusion
- Falls
- Difficulty concentrating
- Memory problems
Alzheimer’s Society advises that some medicines used for bladder problems, anxiety or depression, allergies, Parkinson’s disease, nausea, and long-term pain can worsen confusion or dementia symptoms in some people, while many others are safe and effective.
This is why a complete medication review is often more useful than focusing on one drug from a sensational list.
Does This Mean You Should Stop Your Medication?
Absolutely not—not without medical advice.
Stopping some medicines suddenly can cause withdrawal symptoms, worsening of the original condition, or other serious complications.
If you are worried that a medication is affecting memory, ask your doctor or pharmacist to review:
- Every prescription medicine
- Over-the-counter medicines
- Sleep aids
- Allergy medicines
- Supplements
- The dosage of each medicine
- How long you’ve been taking it
- Possible alternatives
Sometimes a doctor may reduce the dose, change the medication, or choose an alternative with less anticholinergic activity.
Medication-Related Confusion Is Not Always Dementia
This distinction is extremely important.
A person who suddenly becomes confused after starting a new medication may have a drug side effect or delirium, rather than dementia.
Sudden confusion should be medically assessed, particularly when it develops over hours or days.
Dementia generally involves a progressive decline in memory or other thinking abilities that interferes with everyday life.
The Bottom Line
There isn’t a reliable list of “eight drugs that cause severe dementia.”
The evidence is more complicated. Certain medicines—especially those with significant anticholinergic effects—have been associated with cognitive problems and increased dementia risk when used over long periods, particularly in older adults. However, association does not prove that the medication itself caused dementia, and the risk varies by drug, dose, duration, and the individual’s health.
If you or an older family member takes several medications, don’t panic and don’t stop anything suddenly.
Instead, ask a doctor or pharmacist for a medication review. Sometimes a safer alternative or a dose adjustment can reduce cognitive side effects while still treating the original health condition.