The main culprits are the cholinesterase inhibitors, including donepezil, galantamine and rivastigmine, which are causing at least a 10-pound (4.53 kgs) loss in weight in one out of every 21 patients in just a year.
This weight loss often leads to a poorer quality of life, hospital care and even premature death, say researchers from the University of California in San Francisco.
They made the discovery when they monitored 1,188 patients taking cholinesterase inhibitors and compared them to 2,189 elderly patients taking other medications. After a year, nearly 30 per cent of those taking dementia drugs had suffered significant weight loss compared to 22 per cent in the other drug group.
(Source: Journal of the American Geriatrics Society, 2015; doi: 10.111/jgs.13511)