Aging baby boomers are worried about their brainpower. A report in the new England Journal of Medicine (Oct. 6, 2011) notes that three-fourths of people over the age of 60 are concerned about problems with their memory.

Researchers have no clear explanation why memory seems to fade with age. but a recent study from England and Wales suggests that medications may be part of the problem (Journal of the American Geriatrics Society, Aug. 2011). Up to half of the people over the age of 65 were taking one or more drugs that could cause cognitive impairment.

The scientists were especially concerned about medicines that affect the function of the brain chemical acetylcholine. this neurotransmitter is essential for transmitting messages between nerve cells.

A surprising number of medications have anticholinergic activity. These include antidepressants such as amitriptyline, anticonvulsants like carbamazepine and heart drugs such as atenolol, furosemide and nifedipine. There are hundreds of others, including the medicines used to treat overactive bladder, allergy symptoms and anxiety.

Taking such drugs can cause fuzzy thinking, confusion, difficulty reasoning or planning and problems with memory. One reader shared this experience:

“I’m 72 and I have fibromyalgia. I was recently switched from Robaxin to baclofen for muscle spasms.

“I tried baclofen for a few days and realized my mind developed blank spots, like someone used Wite-Out. Two others I know had the same problem. The elderly are apt to be misdiagnosed with dementia due to drugs like this.”

People should never stop taking any prescribed medication without discussing the implications with their doctors. Some of these medicines are crucial for health.

However, the impact of combining several anticholinergic drugs can be devastating. Some people take three or four such medications, increasing the likelihood of cognitive side effects. The British research also found that patients on several anticholinergic medicines were at higher risk of dying prematurely.

It is frequently difficult for physicians to determine how a medication will affect acetylcholine activity and cognitive function in older patients. this kind of information is often left out of publications.

A recent study in the Journal of the American Geriatrics Society (July 2011) evaluated hundreds of studies of medications prescribed for overactive bladder. Three-fourths did not measure or report an impact on brain function. The authors called for more systematic examination of such side effects and better reporting in the medical literature.

Accumulating lots of birthdays can contribute to mental fog and memory problems all by itself. taking medications that have a negative impact on brain function can make the problems worse. Anyone who suspects that a medication could be contributing to confusion or forgetfulness should ask a physician to evaluate this possibility.

Joe Graedon is a pharmacologist. Teresa Graedon holds a doctorate in medical anthropology and is a nutrition expert. Their syndicated radio show can be heard on public radio. in their column, Joe and Teresa Graedon answer letters from readers. Email them via their Web site.