Many people are unaware that dozens of painkillers,antihistamines and psychiatric medications – from drugstore staples to popular antidepressants – can adversely affect brain function,mostly in the elderly. Regular use of multiple medications that have this effect has been linked to cognitive impairment and memory loss.
Called anticholinergics,the drugs block the action of the neurotransmitter acetylcholine,sometimes as a direct action,but often as a side effect. Acetylcholine is a chemical messenger with a range of functions in the body,memory production and cognitive function among them.
The difficulty for patients is that the effect of anticholinergic drugs is cumulative. Doctors are not always aware of all of the medications their patients take,and they do not always think to review the anticholinergic properties of the ones they prescribe. Its a particular problem for older patients,who are more vulnerable to the effects of these drugs and who tend to take more medicines overall.
After following more than 13,000 British men and women or older for two years,researchers found that those taking more than one anticholinergic drug scored lower on tests of cognitive function than those who were not using any such drugs,and that the death rate for the heavy users during the course of the study was 68 per cent higher.
That finding,reported last July in The Journal of the American Geriatrics Society,stunned the investigators.
So far we cant tell why they are dying,but it wasnt because they were sicker or older, said Dr Malaz A Boustani,director of the Wishard Healthy Aging Brain Center and a scientist at the Regenstrief Institute,both in Indianapolis,who was one of the papers authors. We adjusted for age,gender,race,other medications they were taking,other diseases and social status. We adjusted for everything we could,and that signal did not go away.
He added: These are very,very common drugs. Thats the scary piece.
Dr Chris Fox,a senior lecturer at Norwich Medical School at the University of East Anglia in England and the papers lead author,said he suspected that anticholinergics take a toll on bodily organs and systems like the cardiovascular system,although there are no studies confirming this.
Anticholinergics have also been implicated in the delirium that intensive-care patients frequently develop in the hospital. Clinicians dont think of them nearly as often as they should as a potential cause of cognitive problems, said Dr Wesley Ely,a professor of medicine at Vanderbilt University who studies neuropsychological deficits that occur after intensive care hospitalisation.
If you were taking one of the drugs we know is definitely an anticholinergic for 60 days,you doubled the odds of developing mild cognitive impairment compared with a patient taking no anticholinergic medicines,Dr Boustani said.
There is already a consensus in the scientific community that anticholinergic compounds should be prescribed with caution,especially for the elderly.
Dr William Thies,chief medical and scientific officer for the Alzheimers Association,said that studies have shown that up to 25 per cent of the patients who seek help have reversible disorders,including those caused by polypharmacy – taking a combination of medications.
Even so,why do physicians prescribe any medications with anticholinergic activity to elderly people,who may be using them regularly for many years? Not only are doctors often unaware of all the medicines their patients are taking,but the list of drugs with anticholinergic properties is a long one.
The heart drug digoxin,the blood thinner warfarin,the painkiller codeine and prednisone are considered mild anticholinergics. Those with the most severe effects include Paxil,Benadryl,a drug for overactive bladder called oxybutynin,and the schizophrenia drug clozapine.