The U.S. Food and Drug Administration has added a new warning to drugs including Ozempic and Wegovy, cautioning that patients taking the drugs may be at a higher risk of inhaling gastric contents into their lungs while under anesthesia.

The FDA added the warning to most of the drugs earlier this month, according to the agency’s website.

The warning applies to GLP-1 receptor agonists including Ozempic, Wegovy, Rybelsus, Saxenda, Victoza, Mounjaro and Zepbound. The medical news website Medscape first reported the warning label update last week.

GLP-1s — which can be prescribed for diabetes treatment or for weight loss management — have a few effects on the body. One of the drugs’ impacts is to slow down the process of emptying the stomach.

This also means, though, that some patients taking the drugs may still have gastric juices in their stomachs even after following the standard medical guidance on fasting before undergoing anesthesia. For those patients, there have been some rare cases of pulmonary aspiration — or inhaling fluid or food into the lungs — while under anesthesia, according to the new FDA label.

It’s not yet clear if the problem could be solved by changing the pre-anesthesia fasting period or by temporarily halting the use of the GLP-1s, according to the FDA. The FDA said that patients should tell their doctor that they’re taking a GLP-1 before they undergo any surgeries or other procedures.

Medical providers have been aware of the aspiration risk for years, said Dr. Angela Fitch, an obesity specialist and the co-founder of knownwell, a weight-inclusive medical clinic that opened a Plano, Texas location last month.

The majority of patients on GLP-1s are unlikely to have any issues, Fitch said, but the slowed stomach emptying could cause problems for some. Because of that, she said, she would recommend that patients don’t halt the drug ahead of surgery, but instead fast for longer before surgery.