The Medicines and Healthcare products Regulatory Agency (MHRA) has issued updated guidance highlighting a small but significant risk of severe acute pancreatitis for patients using weight-loss and diabetes injections. This move comes in response to a notable increase in adverse reaction reports submitted through the yellow card scheme, which monitors medication safety across the UK.
Understanding the Risk and Patient Impact
Recent data indicates that approximately 1.6 million adults in England, Wales, and Scotland utilised GLP-1 medications such as semaglutide (marketed as Wegovy and Ozempic) and tirzepatide (known as Mounjaro) for weight management between early 2024 and early 2025. Patient information leaflets for these drugs already list pancreatitis as an "uncommon" side effect, estimated to affect around one in every 100 individuals.
Symptoms and Medical Context
Acute pancreatitis involves sudden inflammation of the pancreas, a gland situated behind the stomach that plays a crucial role in digestion. Symptoms can be severe, including intense abdominal pain that may radiate to the back, accompanied by nausea and fever, often necessitating hospital treatment.
While the MHRA emphasises that pancreatitis remains a rare occurrence, the agency has taken proactive steps by revising its safety advice. To date, the yellow card scheme has recorded 1,143 reports of acute and chronic pancreatitis linked to semaglutide and tirzepatide, with 17 fatalities associated. Notably, 973 of these reports were logged in 2025 alone, comprising 807 cases for tirzepatide and 166 for semaglutide.
Additional Data and Pharmaceutical Responses
Further reports include 146 cases for liraglutide and 61 for dulaglutide, underscoring the need for vigilance across all GLP-1 therapies. Dr Alison Cave, the MHRA's chief safety officer, stated: "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 prescribed GLP-1s, these are safe and effective treatments that offer significant health benefits."
She added: "The risk of developing these severe side effects is very small, but it is crucial that both patients and healthcare professionals remain aware and alert to the associated symptoms. If you or someone you care for is taking GLP-1s and experiences symptoms like severe, persistent stomach pain with nausea and vomiting, we advise consulting a healthcare professional and reporting it via our yellow card scheme."
Ongoing Research and Industry Reactions
In a separate development, the MHRA announced that patients using GLP-1 drugs have been recruited for the Yellow Card Biobank study, a collaborative effort with Genomics England. This research aims to investigate whether genetic factors might influence an individual's risk of developing an inflamed pancreas, potentially helping to predict which patients are most susceptible to adverse reactions and guiding safer prescription practices.
Responding to the MHRA's update, a spokesperson for Novo Nordisk, the manufacturer of Wegovy and Ozempic, commented: "Patient safety is of the utmost importance to Novo Nordisk. We recommend that patients use these medications only for their approved indications under strict healthcare supervision, with professional advice on potential side effects. We continuously gather safety data on our marketed GLP-1 medicines and collaborate closely with regulatory authorities to ensure patient safety."
Eli Lilly, the producer of Mounjaro, has been approached for further comment on the matter.
