Some medicines can cause temporary confusion, drowsiness, or memory problems, particularly in older adults. More importantly, research has found an association between long-term use of certain medicines with strong anticholinergic effects and an increased risk of dementia.
But the headline “8 drugs that cause serious dementia” is too absolute. Current evidence mainly shows an association between cumulative exposure to certain medications and dementia; it does not prove that these medicines directly cause dementia in every person who takes them.
A large JAMA Internal Medicine study involving more than 280,000 adults found that higher cumulative exposure to strong anticholinergic medicines was associated with increased dementia risk. The strongest associations were seen with several categories, including certain antidepressants, bladder medicines, antipsychotics, antiparkinson drugs, and antiepileptic medicines.
Here are eight medication categories worth discussing with a doctor or pharmacist.
1. Certain Antidepressants
Some older antidepressants, particularly tricyclic antidepressants, have strong anticholinergic properties.
Examples include:
- Amitriptyline
- Imipramine
- Doxepin
- Clomipramine
These medicines can be effective for certain conditions, so the issue isn’t that everyone taking them should stop.
The concern is particularly relevant to long-term use in older adults, where alternatives may sometimes be available.
In the large JAMA study, cumulative exposure to anticholinergic antidepressants was associated with increased dementia risk.
2. Certain Bladder-Control Medicines
Some medications used to treat overactive bladder work by blocking muscarinic receptors and therefore have anticholinergic effects.
Examples include:
- Oxybutynin
- Tolterodine
- Solifenacin
Long-term exposure to bladder antimuscarinics was among the medication categories associated with dementia in observational research.
This does not mean someone with bladder problems should simply stop treatment. There may be alternative medicines or non-drug approaches worth discussing with a healthcare professional.
3. First-Generation Antihistamines
Some older antihistamines have significant anticholinergic activity.
Examples include:
- Diphenhydramine
- Chlorpheniramine
- Hydroxyzine
Diphenhydramine is found in some over-the-counter allergy and nighttime products.
These medicines can cause drowsiness, confusion, and impaired alertness, particularly in older adults.
Importantly, the evidence concerning long-term dementia risk differs among individual medicines and studies. The concern is primarily about cumulative exposure to medicines with strong anticholinergic effects rather than saying every antihistamine causes dementia.
4. Certain Antipsychotic Medicines
Some antipsychotic medicines have anticholinergic properties, although their clinical uses and risks vary considerably.
Examples include:
- Olanzapine
- Quetiapine
- Clozapine
Antipsychotics can be essential treatments for serious psychiatric conditions, so they should never be stopped suddenly without medical supervision.
In the JAMA observational study, anticholinergic antipsychotic exposure was associated with increased dementia risk.