The UK medicines regulator has advised that patients taking weight-loss jabs and diabetes injections should be aware of a small risk of developing severe acute pancreatitis. The Medicines and Healthcare products Regulatory Agency (MHRA) updated its guidance on Thursday after receiving an increased number of reports of the condition through its yellow card scheme.
Recent research suggests that approximately 1.6 million adults in England, Wales and Scotland used GLP-1 medications, including semaglutide (Wegovy, Ozempic) and tirzepatide (Mounjaro), between early 2024 and early 2025. Pancreatitis is already listed as an uncommon reaction in patient information leaflets, affecting about one in 100 patients.
Acute pancreatitis occurs when the pancreas becomes suddenly inflamed, causing severe abdominal pain, nausea and fever, often requiring hospital admission. To date, the MHRA has received 1,143 reports of acute and chronic pancreatitis among patients taking semaglutide or tirzepatide, with 17 reported fatalities. Nearly all reports (973) were logged in 2025, of which 807 concerned tirzepatide and 166 were related to semaglutide. A further 146 reports related to liraglutide and 61 to dulaglutide.
Dr Alison Cave, the MHRA’s chief safety officer, said: “Patient safety is the MHRA’s top priority and we continually monitor the safety and efficacy of all licensed medicines. For the vast majority of patients who are prescribed GLP-1s, they are safe and effective medicines, which deliver significant health benefits. The risk of developing these severe side effects is very small, but it is important that patients and healthcare professionals are aware and alert to the associated symptoms.”
Separately, the MHRA has recruited patients taking GLP-1s to the Yellow Card Biobank study, a collaboration with Genomics England, to investigate whether genetic factors influence the risk of pancreatitis. The agency hopes this will help predict which patients may be most at risk of adverse reactions and enable safer prescribing.
Novo Nordisk, which makes Wegovy and Ozempic, said patient safety was of utmost importance and recommended that patients take these medications only for approved indications under strict supervision. Eli Lilly, manufacturer of Mounjaro, noted that its patient information leaflet warns that acute pancreatitis is an uncommon side-effect and advised patients to consult a healthcare professional regarding any side-effects.
