Common Drugs May Raise Alzheimer's Risk
Common Drugs May Raise Alzheimer's Risk
July 25, 2003 -- Drugs often used by patients with Parkinson's disease may increase their risk of another killer brain disease: Alzheimer's.
The drugs -- called anticholinergic agents -- slow electrical impulses in nerve cells. They're used to help Parkinson's disease patients control unwanted movement such as tremors. These drugs also help with bladder control and dizziness. But other common drugs have anticholinergic activities, too. These include older allergy drugs and tricyclic antidepressants.
The report in the August issue of Annals of Neurology comes from Elaine K. Perry, PhD, senior scientist at University of Newcastle upon Tyne and colleagues. Perry's team examined the brains of deceased Parkinson's patients for the plaques and tangles seen in the brains of Alzheimer's patients.
The result: Those who took anticholinergic drugs for more than two years had significantly more plaque and tangles than those who never took the drugs. Taking the drugs for less than two years had no effect.
"What we saw were very, very low levels of Alzheimer's disease pathology, nothing like what you would see in Alzheimer's disease," Perry tells WebMD. "The drugs might increase this pathology, but they are not taking people into Alzheimer's disease."
But Allan Levey, MD, PhD, chair of the neurology department at Emory University School of Medicine, says these patients may have been on the way to Alzheimer's. Levey's commentary appears in the same issue of Annals of Neurology.
"If these people with Parkinson's disease had lived longer, they might have developed Alzheimer's disease," Levey tells WebMD.
The category of drugs linked to Alzheimer's changes aren't now the front-line drugs for Parkinson's disease. One reason is that they can have terrible side effects. Medical students remember these side effects by learning a series of similes:
The drugs -- called anticholinergic agents -- slow electrical impulses in nerve cells. They're used to help Parkinson's disease patients control unwanted movement such as tremors. These drugs also help with bladder control and dizziness. But other common drugs have anticholinergic activities, too. These include older allergy drugs and tricyclic antidepressants.
The report in the August issue of Annals of Neurology comes from Elaine K. Perry, PhD, senior scientist at University of Newcastle upon Tyne and colleagues. Perry's team examined the brains of deceased Parkinson's patients for the plaques and tangles seen in the brains of Alzheimer's patients.
The result: Those who took anticholinergic drugs for more than two years had significantly more plaque and tangles than those who never took the drugs. Taking the drugs for less than two years had no effect.
"What we saw were very, very low levels of Alzheimer's disease pathology, nothing like what you would see in Alzheimer's disease," Perry tells WebMD. "The drugs might increase this pathology, but they are not taking people into Alzheimer's disease."
But Allan Levey, MD, PhD, chair of the neurology department at Emory University School of Medicine, says these patients may have been on the way to Alzheimer's. Levey's commentary appears in the same issue of Annals of Neurology.
"If these people with Parkinson's disease had lived longer, they might have developed Alzheimer's disease," Levey tells WebMD.
Alzheimer's Risk in Widely Used Older Drugs
The category of drugs linked to Alzheimer's changes aren't now the front-line drugs for Parkinson's disease. One reason is that they can have terrible side effects. Medical students remember these side effects by learning a series of similes:
- "Mad as a hatter." Anticholinergic drugs can make patients delirious.
- "Blind as a bat." The drugs can dilate the pupils of the eye, making it hard to see.
- "Red as a beet." Flushing is a common side effect.
- "Dry as a bone." Dry skin is another side effect.
- "Hot as a hare." The drugs can cause overheating or hyperthermia.
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