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Drug-Induced Memory Loss

Posted by medconsumers on June 1, 2008

Memory Loss and the Drugs That Can Cause It

Memory loss, cognitive impairment, dementia, Alzheimer’s disease. As the media frequently remind us, all these problems will soon reach epidemic proportions because more and more Americans are living to an advanced age. Virtually no media attention has been given to the research that is slowly building a case against one large category of prescription drugs linked to a more rapid decline in cognitive function in older people. Known as anticholinergics, these drugs include everything from antihistamines and bronchodilators to blood-thinners and anti-nausea medicines.

The latest study to indict anticholinergic drugs was presented recently at the annual meeting of the American Academy of Neurology. As reported on Medscape, the on-line news service, one woman’s experience with Detrol, a drug for overactive-bladder symptoms, provided the impetus for the new study. It was led by Jack Tsao, MD, associate professor of neurology at the Uniformed Services University of the Health Sciences, Bethesda, MD.

The woman went to her doctor with memory difficulty and hallucinations, Dr. Tsao explained, but tests showed that she did not have Alzheimer’s-type dementia. The focus then went to Detrol (generic name: tolterodine), which she had just started taking. Fortunately, her doctor recalled the experience of another patient on the same drug with the same symptoms. That patient’s problems had resolved once the drug was stopped.

The experiences of these two patients prompted Dr. Tsao to contact researchers at Rush University in Chicago, who scrutinized data generated by a large study that has been following nearly 900 older Catholic nuns and clergy ever since it began in 1993. The stated aim of the Rush Religious Orders Study is “to discover what changes in the brain are responsible for memory and movement problems” and “to look closely at the transition from normal functioning of the aging brain to the mild cognitive impairment that can be an early sign of Alzheimer’s disease.” At the time of enrollment, all participants were free of dementia.

Tsao and colleagues found that cognitive decline was more rapid after participants began to use anticholinergic drugs compared to those who did not take these drugs. In a telephone interview, Dr. Tsao emphasized a key discovery about those on anticholinergics. “Even though their cognitive performance was worse, we did not find that they were at an increased risk of being diagnosed with Alzheimer’s disease or dementia.”

Although Dr. Tsao’s study is preliminary, its findings are consistent with those of earlier studies. One, for example, was conducted in France and published in 2006 in the British Medical Journal. Unlike the Religious Orders Study, this one recruited people over age 60 specifically to assess the “potential of anticholinergic drugs as a cause of non-degenerative mild cognitive impairment.”

The 372 participants were given annual cognitive performance assessments as well as blood tests. Over 9% had continuously used anticholinergic drugs during the years before their cognitive skills were tested. “Compared with non-users, they had poorer performance on reaction time, attention, delayed non-verbal memory, narrative recall, visuospatial construction, and language tasks but not on tasks of reasoning, immediate and delayed recall of word lists, and implicit memory,” wrote the French researchers led by Dr. Marie I. Ancelin.

Similar to Dr. Tsao’s conclusion, Ancelin and colleagues found that mild cognitive impairment does not put someone on the path to dementia: “Although the consistent users of anticholinergic drugs were significantly more likely to have a diagnosis of mild cognitive impairment at one-year follow-up (80%) than consistent non-users (35%), we found no difference in overall dementia rates at eight-year follow-up between the drug users and non-users.”

Then there’s the problem of drug interactions. The French researchers noted that it would be inappropriate, even counterproductive, for doctors to prescribe acetylcholinesterase inhibitors to people who are already taking an anticholinergic drug. Sold under brand names of Aricept, Exelon and Razadyne, acetylcholinesterase inhibitors are an aggressively promoted, but minimally effective, class of drugs prescribed for Alzheimer’s and dementia.

Dr. Tsao was asked whether doctors know these two classes of drugs should not be prescribed together. “There have been published reports of people who were taking anticholinergics and then being started on Aricept. So you are pushing and pulling on the same system with different antagonistic drugs. One is inhibiting the anticholinergic system, and the other is trying to enhance it. It’s a common concern among nursing home patients with dementia. They’re already on Aricept and then they are given an anticholinergic, which defeats the purpose.”

Ancelin and colleagues had their own warning about prescribing practices. “Not only do doctors commonly fail to associate cognitive dysfunction in elderly people with anticholinergic agents, they also underestimate anticholinergic toxicity, prescribing such drugs at high to excessive doses.”

What you can do:

  • If you must take an anticholinergic drug for a chronic condition, question your doctor about the dose. It may be possible to lower the dose without losing effectiveness.
  • See below for a partial list of anticholinergics.
  • Exercise regularly. In her new book entitled, “Can’t Remember What I Forgot,” (Harmony Books), Sue Halpern found aerobic exercise is the only memory improvement remedy that has good studies to back it up (and she looked at everything from drugs and supplements to fish oil and crossword puzzles). Brisk walking is enough because no additional benefit is shown for extreme or prolonged exercise. Eat lots of blueberries, too.
  • Drink at least three cups of coffee, or six cups of tea, per day. Caffeine protected women over age 65 years from cognitive decline, compared to women who drink one cup or less, according to studies published last year in the journal Neurology.

Maryann Napoli, Center for Medical Consumers ©
June 2008

Is Your Drug an Anticholinergic?

Ask your pharmacist or doctor whether a drug you are taking is an anticholinergic. The usual advice—read the written material that comes with the drug—does not hold in this case. The much-abridged list of anticholinergics below came from a medical journal, but a spot check of the written information that comes with these drugs failed (with one exception) to mention the word anticholinergic.

Lomotil, Lofene, Logen, and many other drugs that contain atropine for diarrhea;

Detrol, Enablex, Trospium, Ditropan for overactive bladder;

Hyosol, Hyospaz for disorders of the gastrointestinal tract;

Prednisone Intensol, Sterapred for certain types of arthritis, severe allergic reactions, etc;

Bronkodyl Elixophyllin, Slo-bid, Theo-24 and other drugs containing theophylline for asthma, chronic bronchitis and other lung diseases;

Codeine for pain and inflammation. Sold under more than two dozen brand names and present in more than 30 combination products;

Xanax, Alprazolam Intensol for anxiety disorders and panic attacks; Valium and Diazepam Intensol for anxiety disorders, muscle spasms, and seizures;

OxyContin, Oxydose, Roxicodone for moderate to severe pain;

Capoten, or captopril, for hypertension and heart failure;

Lasix to reduce the swelling and fluid retention caused by various medical problems, heart or liver disease. It is also used to treat high blood pressure.

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