Medical watchdogs have warned clinicians and patients to ‘be alert’ to an infrequent but potentially ‘severe’ complication of the injections
People using GLP-1 jabs have been urged to watch for one rare but potentially serious side effect. The Medicines and Healthcare products Regulatory Agency (MHRA) has issued a fresh warning to doctors to be aware of the possible complication.
While the body was aware of the potential for those taking GLP-1 medication such as Ozempic, Wegovy and Mounjaro to develop severe inflammation of the pancreas it has now issued new guidance to remind both doctors and those taking the injections of what to look for. And it says if you develop the symptoms to seek medical help immediately.
The pancreas is a small organ, located behind the stomach, that helps with digestion. However this can become inflamed and swollen leading to extreme pain in the stomach and back that does not go away.
If this happens over a short period of time it is known as acute pancreatitis. While people will usually start to feel better within about a week and have no further problems, some with severe acute pancreatitis can go on to develop serious complications, the NHS says.
The MRHA has now updated the product information for healthcare professionals and patients, including those taking the medication to lose weight, to ensure they are aware of the risk. Alison Cave, 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.
“If you, or someone you care for, is taking GLP-1s and you notice symptoms such as severe, persistent stomach pain that may radiate to the back and may be accompanied by nausea and vomiting, then we advise you speak to a healthcare professional and report it via our Yellow Card scheme.”
Wegovy and Mounjaro are both licensed to be prescribed for weight loss while Ozempic is licensed for treating diabetes as well as reducing the risk of heart attack and stroke. In a statement the MHRA said: “GLP-1s are prescribed for the treatment of type 2 diabetes and, for some products, weight management, and cardiovascular risk reduction in individuals with established cardiovascular disease and a BMI of 27 kg/m2 or more.
“Research recently published by University College London estimates that 1.6 million adults in England, Wales and Scotland used GLP-1s, such as semaglutide (Wegovy, Ozempic) and tirzepatide (Mounjaro), between early 2024 and early 2025, to lose weight.
“While GLP-1s are generally considered safe and effective for their authorised uses, like all medications they are not without risk. Those taking GLP-1s should be aware of the symptoms of severe pancreatitis and seek urgent medical attention if they experience them.”
Symptoms of acute pancreatitis
According to the NHS the most common symptoms of acute pancreatitis include:
- suddenly getting severe pain in the centre of your tummy (abdomen)
- feeling or being sick
- a high temperature of 38C or more (fever)
When to get medical help
The NHS advises: “See a GP immediately if you suddenly develop severe abdominal pain. If this isn’t possible, contact NHS 111 for advice.”

