Nursing home patients who take antipsychotic drugs are 60 percent more likely to develop pneumonia in the short term than those who don’t take the drugs, according to a study in the Journal of the American Geriatrics Society. The risk is greatest during the first week after patients start taking the meds, but gradually decreases, HealthDay News reports.

“The risk of developing pneumonia is not associated with long-term use, but is the highest shortly after starting the drug,” according to the study authors, Rob van Marum and Wilma Knol. They warned that “all antipsychotic drugs may be associated with pneumonia in elderly patients.”

Up to 40 percent of nursing home residents may be prescribed antipsychotics, according to the study. They noted that, in more than half of those cases, antipsychotics are prescribed for inappropriate reasons. The drugs are often used to treat behavioral problems in dementia patients, but evidence shows these drugs have limited effectiveness in these patients, HealthDay writes. In addition, recent research has shown that the use of antipsychotics in elderly patients is associated with an increased risk of illness and death.

This is the first study to show an association between pneumonia risk and the use of antipsychotics, which are frequently used to treat psychosis and behavioral problems in elderly patients with dementia and delirium, HealthDay writes. But more research is needed to identify the underlying mechanism behind this association, according to the researchers, who added that docs should monitor elderly patients for signs of sedation after they start taking antipsychotics and should carefully weigh the possible risks before they prescribe the meds for elderly patients.