Weight Loss Drug Users Face Significantly Higher Risk of Surgical Complications, Study Warns

Patients undergoing surgery who are taking weight loss medications such as Mounjaro and Wegovy face an elevated risk of life-threatening complications, according to a recent study. Researchers found that individuals using these drugs, known as GLP-1 receptor agonists (GLP-1 RAs), were 11 times more likely to experience regurgitation and pulmonary aspiration while under anesthesia compared to those not taking the medications.

Pulmonary aspiration occurs when stomach contents move up into the throat during sedation, potentially entering the lungs. This can lead to airway obstruction, lung damage, pneumonia, and in severe cases, sepsis or suffocation. The study suggests that the increased risk may be linked to the way GLP-1 drugs slow down digestion, causing food to remain in the stomach longer. This effect can persist even if patients follow pre-operative fasting instructions, meaning their stomachs may not be empty when anesthesia is administered.

Scientists from Guy's and St Thomas' NHS Foundation Trust and King's College London analyzed data from 47,039 patients across 119 UK hospitals. Of these, 1,348 were taking GLP-1 drugs. The complication rate in this group was 1.4%, or about one in 71 patients, with over half of incidents occurring as patients awoke from anesthesia. In contrast, the complication rate among patients not taking these drugs was 0.12%, with one fatality reported in that group.

An estimated 2.5 million people in the UK are currently using GLP-1 drugs. The study's authors, who presented their findings at the Association of Anaesthetists Annual Meeting, emphasized the importance of patients informing their anesthesiologists about their use of these medications. They also recommended that anesthesiologists specifically inquire about GLP-1 RA use prior to procedures.

The study also noted that while nearly a third of GLP-1 users in the analysis had been advised to stop taking the drugs before surgery, UK guidance currently recommends continuing them due to a lack of clear evidence that stopping them reduces risk. It also highlights that stopping treatment can have its own adverse effects, particularly for diabetic patients. Instead, the advice focuses on identifying patients on these drugs and implementing extra precautions.

Despite the increased risk, researchers stated that the overall likelihood of these complications remains low. They also cautioned that the study observed a link, but could not definitively prove causation, noting that obesity and diabetes—conditions for which the drugs are prescribed—are themselves known risk factors for such complications.

Eli Lilly, the maker of Mounjaro, acknowledged the findings, stating that product information warns of reported pulmonary aspiration cases in patients undergoing general anesthesia or deep sedation. They advise that the increased risk of residual gastric content due to delayed gastric emptying should be considered. Novo Nordisk, the manufacturer of Ozempic and Wegovy, was also contacted for comment.

This research follows previous reports of adverse reactions associated with GLP-1 drugs, including nearly 150,000 suspected adverse reactions and 216 deaths reported in official drug safety analyses last month. Most of these reports involved gastrointestinal issues, though officials have stressed that such reports do not prove the medications caused the outcomes.