These common drugs may increase dementia risk

The link between certain commonly used drugs and an increased risk of dementia, particularly anticholinergic medications, is a significant area of research. Here’s a detailed breakdown of what is known.

The Main Culprit: Anticholinergic Drugs

The strongest evidence points to a class of drugs known as anticholinergic medications. These drugs work by blocking acetylcholine, a key neurotransmitter in the nervous system that is vital for memory, learning, and muscle function.

• How they might increase risk: Chronic blockage of acetylcholine is thought to interfere with brain cell communication and may contribute to the pathology of diseases like Alzheimer’s. The risk appears to be dose-dependent and linked to long-term use.

Common Types of Anticholinergic Drugs Linked to Higher Risk

Research has found that certain categories of anticholinergics carry a stronger risk than others. The following types are most commonly associated with increased dementia risk:

1. Anticholinergic Bladder Antimuscarinics (for overactive bladder)

• Examples: Oxybutynin (Ditropan), Tolterodine (Detrol), Solifenacin (Vesicare).
• Why they’re notable: Studies have often found these medications to be among the most strongly linked to dementia risk.

2. Anticholinergic Antidepressants (Tricyclic antidepressants)

• Examples: Amitriptyline (Elavil), Doxepin, Paroxetine (Paxil – an SSRI with strong anticholinergic properties).
• Note: Not all antidepressants carry this risk. Newer SSRIs like sertraline (Zoloft) and citalopram (Celexa) have very low anticholinergic activity.

3. Anticholinergic Antipsychotics (First-generation or “typical”)

• Examples: Chlorpromazine, Thioridazine, Haloperidol (in high doses).

4. Anticholinergic Antihistamines (First-generation)

• Examples: Diphenhydramine (Benadryl, and also a common sleep aid like in ZzzQuil), Chlorpheniramine, Doxylamine (Unisom).
• Note: Newer second-generation antihistamines like loratadine (Claritin) and fexofenadine (Allegra) do not significantly cross the blood-brain barrier and are not linked to this risk.

5. Anticholinergic Anti-Parkinson’s Drugs

• Examples: Benztropine, Trihexyphenidyl.

6. Anticholinergic Antispasmodics (for GI cramps)

• Examples: Dicyclomine (Bentyl), Hyoscyamine (Levsin).

Key Findings from Major Studies

• A 2019 large-scale study published in JAMA Internal Medicine found that use of anticholinergic medications was associated with a dose-dependent increased risk of dementia.
• The study suggested that taking a strong anticholinergic drug daily for three years or more was associated with the highest increased risk.
• It’s important to note that these studies show an association, not direct causation. However, the biological mechanism (blocking acetylcholine) provides a plausible explanation for the link.

What This Means For You: Important Considerations

1. Do NOT Stop Taking Prescribed Medication: This is the most critical point. Suddenly stopping necessary medication can be very dangerous. The risk of untreated depression, Parkinson’s disease, or bladder conditions may far outweigh a potential future risk of dementia.
2. Talk to Your Doctor (Deprescribing): If you or a loved one has been taking these medications long-term, have a conversation with your doctor or pharmacist. Ask:
   • “Is this drug absolutely necessary?”
   • “Are there effective alternatives with less anticholinergic activity?”
   • “Can the dose be reduced?”
     This process is known as deprescribing.
3. Risk is Highest with Long-Term, High-Dose Use: Occasional use of Benadryl for an allergic reaction is unlikely to pose a significant threat. The primary concern is with cumulative, long-term use.
4. Review All Medications: Especially for older adults who may be on multiple medications (polypharmacy), a regular review with a doctor or pharmacist is essential to identify potential risks and interactions.

Summary Table: Common Drugs and Alternatives

Final Takeaway: Be aware that some common medications, particularly those with strong anticholinergic effects, are associated with a higher risk of dementia when used heavily over long periods. The best course of action is to have an informed conversation with your healthcare provider about the risks and benefits of all your medications. They can help you find the safest and most effective treatment plan for your individual health needs.