If there were more than 50 prescription and over-the-counter (OTC) medications that had been linked to an increased risk for Alzheimer’s disease and other related dementias, you’d think that everyone would avoid those drugs—­especially when safer alternatives are often available. But that’s not happening.

Sobering new finding: When medications known as anticholinergics are taken for three or more years, previous research has linked them to about a 50% higher risk for dementia, but a new finding shows that these medications are still being widely used to treat conditions ranging from the common cold, allergies and incontinence to Parkinson’s disease, motion sickness and muscle pain. To protect yourself and your loved ones…

What Are Anticholinergics?

More than 10 million Americans, age 65 and older, use anticholinergic drugs. The medications block the action of acetylcholine, a neurotransmitter (brain chemical) that activates many key body functions involving muscles, the heart, digestive system, lungs, urinary tract and blood vessels. These drugs, which include medications from various drug classes, also have effects on the brain and are used to treat dizziness, nausea, epilepsy and depression.

Well-documented side effects from these drugs include dry mouth and constipation. Because these medications also affect the brain, they can cause confusion and memory loss. Older adults are at highest risk for dementia from these drugs because they tend to take more of them than younger adults. Older adults also are at increased risk for dementia due to their age—in part, because acetylcholine production declines as people grow older. 

New Study Sounds The Alarm

In the study mentioned earlier, which was published in JAMA Internal Medicine, the medical records of about 225,000 patients (ages 55 to 100) who had not been diagnosed with dementia were compared with those of about 60,000 dementia patients to see how many in each group had taken a ­prescription-strength anticholinergic drug during an 11-year period.

The researchers found that 57% of the dementia patients and 51% of the non-dementia patients had been prescribed at least one of the 56 anticholinergic drugs included in the study. The most commonly used drugs were prescribed to treat depression, dizziness, nausea, vomiting and bladder spasms. Other key findings…

• Greater exposure, bigger risk. Patients who took an anticholinergic on a daily basis for three years had a 49% higher risk of being diagnosed with dementia than patients with no exposure. Those who took one of the drugs for less than three months had a 6% increased risk.

• Some drugs are riskier than others. The highest-risk anticholinergics included antipsychotics, such as olanzapine (Zyprexa) or quetiapine (Seroquel)…overactive bladder medications, including tolterodine (Detrol) and oxybutynin (Ditropan)…anti-parkinsonian drugs, such as benztropine (Cogentin)…antiepileptics, including carbamazepine (Tegretol) and oxcarbazepine (Trileptal)…and antidepressants, such as amitriptyline (Elavil) and paroxetine (Paxil). 

Even though these findings are ­observational (that is, they do not prove cause and effect), they are consistent with earlier research. For this reason, the researchers recommend that doctors carefully weigh the risks and benefits of prescribing these drugs for patients who are middle-aged and older and strongly urge the use of other effective drugs, that are not anticholinergics, whenever possible.

What Should You Do?

To avoid the potential harms of anticholinergics, you should know which medications have been linked to the greatest dementia risk. 

To get a clearer picture of the risk associated with the most widely used anticholinergic drugs on the market, consult the Anticholinergic Cognitive Burden (ACB) Scale, which ranks both prescription and OTC anticholinergic drugs, according to their degree of risk.

If you are taking a prescription drug that appears on the list, talk to your doctor. Ask if you can stop taking the drug…or if there is a suitable substitute that is safer for you. For example, if you are taking an antidepressant on the ACB Scale, sertraline (Zoloft) or citalopram (Celexa) may be a safer choice, since each has minimal anticholinergic effects. Caution: Never stop taking a medication that your doctor has prescribed without consulting him/her.

It’s also worth noting that many OTC anticholinergics are considered high risk. Among the most widely used are the antihistamines diphenhydramine (Benadryl) and chlorpheniramine (Chlor-Trimeton)…the cold and allergy medicine brompheniramine-PPA (Dimetapp)…and the motion-sickness drug dimenhydrinate (Dramamine). 

If you take an OTC anticholinergic frequently (one pill for 60 days in a 12-month period), ask your doctor or pharmacist if you really need it. You can also ask if there is a substitute drug that is not an anticholinergic. 

Important: Dementia risk linked to these drugs is added to any other risk factors you may have, such as older age…high blood pressure…diabetes…­inactivity…a family history of dementia…and smoking. For this reason, your entire risk profile should be considered when discussing the use of these drugs with your doctor.