Hundreds of people have reported problems with their pancreas linked to taking weight loss and diabetes injections, prompting UK health officials to launch a study into side-effects. Some cases of pancreatitis reported to be linked to GLP-1 medicines have been fatal.
The Medicines and Healthcare products Regulatory Agency (MHRA) has seen an increase in reports of acute pancreatitis through its Yellow Card scheme, which monitors adverse reactions. Acute pancreatitis is a sudden inflammation of the pancreas that often requires hospital admission, with symptoms including severe abdominal pain, nausea and fever.
To date, the scheme has received nearly 400 reports of acute pancreatitis from patients using Mounjaro, Wegovy, Ozempic and liraglutide. Nearly half (181) involved tirzepatide (Mounjaro). More than a quarter of these cases have been reported in 2025, with 22 reports linked to semaglutide (Ozempic and Wegovy) and 101 to tirzepatide since the start of the year.
The MHRA is now inviting patients hospitalised with suspected drug-related acute pancreatitis to join the Yellow Card Biobank study, run by Genomics England, to investigate possible genetic factors. Participants will provide a saliva sample for analysis. Dr Alison Cave, MHRA chief safety officer, said evidence shows almost a third of side-effects could be prevented with genetic testing, and adverse drug reactions cost the NHS over £2.2bn a year in hospital stays.
Both Lilly, maker of Mounjaro, and Novo Nordisk, maker of Ozempic and Wegovy, stressed patient safety and noted that pancreatitis is listed as an uncommon side-effect in patient information leaflets. They urged patients to use the medications only under healthcare professional supervision and to report any adverse events via the Yellow Card scheme.
