Study: Acetylcholine-Blocking Drugs May Increase Risk of Alzheimer's

Acetylcholine-blocking drugs used to treat the symptoms of Parkinson's disease as well as depression and hypertension may increase the risk of Alzheimer's disease, according to a study reported in the July 25 on-line edition of the Annals of Neurology.

Researchers in England examined the brains of people who had died with Parkinson's disease, looking for evidence of the plaques and tangles that typify Alzheimer's disease.

They found that patients who had taken acetylcholine-blocking drugs called muscarinic antagonists for more than two years had twice as many plaques and tangles as patients who took the drugs for less than two years, or not at all.

"These findings suggest that chronic use of muscarinic antagonist drugs in the elderly should be avoided," said lead author Elaine K. Perry, of Newcastle General Hospital in England.

In an accompanying editorial, Dr. Allan Levey, of Emory University in Atlanta, said the study raises questions about a wide range of drugs since some antidepressants, antihypertensives, antipsychotics and antihistamines also block acetylcholine.

"If future studies provide additional and more direct evidence demonstrating a more serious effect of anticholinergics on Alzheimer's disease pathology, and long-lasting clinically significant cognitive and/or behavioral changes, then common use of anticholinergics will have to be further questioned," said Levey.

Other sources: American Neurological Association