Health officials in the UK have launched a major investigation into reports of acute pancreatitis linked to GLP-1-based weight loss and diabetes medications such as Ozempic, Wegovy, Mounjaro, and liraglutide, after hundreds of adverse cases were flagged. Since early 2025, more than 120 cases of acute pancreatitis have been reported following use of these drugs, with tirzepatide (Mounjaro) alone accounting for over 100 cases so far this year.
The Medicines and Healthcare products Regulatory Agency (MHRA) is responding to a noticeable increase in complaints submitted to its Yellow Card scheme, which monitors suspected side effects from medications.
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Acute pancreatitis, a sudden and painful inflammation of the pancreas, often requires hospitalisation. Symptoms include severe abdominal pain, nausea, and fever. Although patient information leaflets describe it as an “uncommon” side effect, potentially affecting up to 1 in 100 users, the MHRA is concerned about the rising trend in reports, some of which have been fatal.
The MHRA has partnered with Genomics England to launch the Yellow Card Biobank study, which will investigate whether genetic factors may increase a person’s risk of developing severe reactions to GLP-1 receptor agonists. Patients hospitalised with suspected drug-related pancreatitis are being encouraged to report to the Yellow Card scheme, and they may be invited to submit additional information and a saliva sample for genetic testing.
“There is growing evidence that a person’s genes can affect how they respond to medications,” said Dr. Alison Cave, MHRA’s Chief Safety Officer. “We know that almost a third of medicine side effects could be avoided through genetic screening — and this could be a step toward safer prescribing.”
Pharmaceutical companies, including Lilly (maker of Mounjaro) and Novo Nordisk (maker of Ozempic and Wegovy), have reiterated their commitment to patient safety, urging users to consult healthcare professionals and adhere strictly to approved usage guidelines.
Despite the rising concerns, the MHRA emphasised that GLP-1 drugs continue to offer significant benefits for managing obesity and type 2 diabetes. The current investigation aims to ensure these treatments remain both effective and safe for the growing number of users.
