Common dementia medications can cause harmful weight loss in some patients, new research shows.

The findings, by University of California-San Francisco scientists, underscore the need for clinicians take into account for the risks — as well as the potential benefits — of prescribing such drugs to older adults.

"This is very relevant to patient care because unintentional weight loss in older adults is associated with many adverse outcomes, including increased rates of institutionalization and mortality, a decline in functional status, and poorer quality of life," said lead researcher Meera Sheffrin, M.D., with the UCSF School of Medicine at the UCSF-affiliated San Francisco VA Medical Center.

"Our study provides evidence in a large, real-world population that cholinesterase inhibitors may contribute to clinically significant weight loss in a substantial proportion of older adults with dementia."

The study, published in the Journal of the American Geriatrics Society, found that the class of medications called cholinesterase inhibitors (including donepezil, galantamine, and rivastigmine) are only marginally beneficial for most patients and may have serious side effects such as weight loss and gastrointestinal symptoms.

The researchers’ conclusions are based on an analysis of national VA records of patients diagnosed with dementia who received a new prescription for a cholinesterase inhibitor or other new chronic medication. Most experienced an average 10-pound weight loss over a 12-month period, representing a degree of loss that is concerning.

"Clinicians should take into account the risk of weight loss when weighing the risks and benefits of prescribing cholinesterase inhibitors in patients with dementia," the authors wrote. "In addition, clinicians should monitor for weight loss if these medications are prescribed and consider discontinuing cholinesterase inhibitors if significant weight loss occurs."