UK Warns of Pancreatitis, Deaths Tied to Obesity Drugs Wegovy, Mounjaro

The UK warned some patients have died of severe inflammation of the pancreas linked to obesity and diabetes drugs such as Eli Lilly & Co.’s Mounjaro and Novo Nordisk A/S’s Wegovy.

Though the worst cases of pancreatitis were rare, the UK Medicines and Healthcare products Regulatory Agency said Thursday doctors and patients should know some incidents had been particularly severe, as it strengthened its warning over taking the drugs.

The guidance applies to medicines that mimic the GLP-1 gut hormone, like Wegovy, as well as drugs that imitate a second hormone called GIP. Mounjaro falls in this category. Both already carry similar warnings in the US.

Novo said patients should only take these medications when under the supervision of a health professional who can advise them on side effects, and that the benefit-risk profile of GLP-1 medicines remains positive.

Lilly said an inflamed pancreas may affect as many as 1 in 100 people and advised patients to talk to their doctors before using Mounjaro if they’ve ever had pancreatitis. The drugmaker said it takes reports regarding patient safety seriously and will work with prescribers to ensure they have appropriate safety information.

The UK agency received almost 1,300 reports of the condition associated with the drugs from 2007 to October 2025. They include 19 deaths and 24 cases of necrotizing pancreatitis, in which tissue in the pancreas dies. About 25 million packs of the drugs have been dispensed in the UK in the past five years.

The agency advised people taking the obesity drugs to seek a doctor if they experience severe and persistent abdominal pain that may radiate to the back, potentially alongside nausea and vomiting.

It also advised doctors to ask patients with such symptoms whether they’d been taking the drugs, given the risk that if they were bought privately they might not appear on a patient’s medical history held by the National Health Service.

Photograph: Wegovy injection pens; photo credit: Shelby Knowles/Bloomberg