Medication fog can mimic dementia

Doctors studying polypharmacy say prescription side effects can be mistaken for worsening confusion.

Claire Dinneen’s daughters thought that worsening dementia was causing her growing confusion, but her doctor suspected something else.

Dr. Pei Chen asked them to round up medicines in the 89-year-old woman’s home and they returned with a huge haul. There were 28 drugs ordered by various doctors for various ailments, plus overthe-counter medicines. Chen spent a year sorting out which ones were truly needed and trimmed a dozen.

To her daughters’ surprise, Dinneen got better, able to remember more things and to offer advice on what to wear and how to raise their kids. Her symptoms were from “medication fog,” not her dementia getting worse, Chen told one daughter.

“Unfortunately, it’s not unusual,” said Chen, a geriatrician at the University of California, San Francisco.

About 91% of people over 65 take at least one prescription medicine and 41% use five or more — what doctors call polypharmacy.

The risk of side effects or interactions rises with the number of pills, and one doctor often is unaware of what others have already prescribed for the same patient. Dinneen had two prescriptions for the same drug at different doses from different pharmacies.

“It’s very easy to miss medication side effects because they masquerade as all these other symptoms,” said Dr. Michael Steinman, another UCSF geriatrician.

He recently helped update an American Geriatrics Society list of potentially inappropriate medicines for older adults that can mimic dementia or make symptoms worse.

“Potentially” is the key word — the drugs on the list don’t always pose a problem, and no one should stop using any medicine without first checking with a doctor because that could do serious harm, Steinman stressed.

But some medicines don’t have a strong reason to be used and their risks may outweigh their benefits for older people, he and other doctors say. They often “deprescribe” medicines that may no longer be needed or that once may have been OK but now may be causing problems.