Weight Loss Drugs Linked to Significantly Higher Risk of Surgical Complications, Study Finds

Patients taking popular weight loss medications face a substantially increased risk of dangerous complications during surgery, according to a new study. Researchers found that individuals using drugs like Mounjaro and Wegovy were 11 times more likely to experience regurgitation, where stomach contents flow back into the throat during anesthesia, and pulmonary aspiration, when this material enters the lungs.

Pulmonary aspiration can lead to blocked airways, severe lung damage, pneumonia, and potentially fatal sepsis. The findings, presented at the Association of Anaesthetists Annual Meeting and published in the journal Anaesthesia, analyzed data from over 47,000 patients across 119 UK hospitals.

Of the patients studied, 1,348 were taking GLP-1 receptor agonists, the class of drugs that includes Mounjaro and Wegovy. Among this group, 1.4% experienced regurgitation or pulmonary aspiration, translating to about one in 71 patients. This is in stark contrast to the 0.12% of patients not taking these drugs, among whom one fatality was reported.

Experts believe the heightened risk is linked to the mechanism of GLP-1 drugs, which mimic a gut hormone to slow digestion and increase feelings of fullness. This effect means that even when patients fast before surgery, their stomachs may not be entirely empty. The complication occurred in over half of the incidents as patients were waking from anesthesia.

The study authors emphasized the importance of patients informing their anesthesiologists if they are taking GLP-1 medications. "As use of GLP-RAs is increasing, it remains good practice for anaesthetists to consider specifically asking patients if they are taking these medications before anaesthesia," the researchers stated.

While UK guidance often suggests patients continue taking these drugs, some were advised to stop them before surgery, typically for one to two weeks. However, there is limited evidence that stopping briefly reduces risk, as the drugs' effects can linger. Moreover, abruptly stopping treatment can cause issues, particularly for diabetic patients.

The researchers noted that while the overall risk of these complications remains low, the study could not definitively prove causation, only an observed association. They also pointed out that obesity and diabetes, conditions for which these drugs are prescribed, are themselves known risk factors for these surgical complications.

Eli Lilly, the maker of Mounjaro, acknowledged the findings, stating that patient safety is a top priority. The company's product information already warns of reported cases of pulmonary aspiration in patients undergoing anesthesia while receiving GLP-1 receptor agonists, recommending that the increased risk of residual gastric content be considered prior to procedures. Novo Nordisk, the manufacturer of Ozempic and Wegovy, was also contacted for comment.

This research emerges amid increased scrutiny of weight loss drugs. Reports last month indicated around 150,000 suspected adverse reactions, including 216 deaths, linked to their use, although officials stressed these reports do not prove causation. Most reported issues involved gastrointestinal problems like pancreatitis and gastroparesis.