The MHRA has issued new guidance to doctors and patients taking GLP-1 drugs to watch for symptoms of a rare but potentially serious side effect
People taking GLP-1 drugs have been issued a warning over an uncommon but potentially serious side effect. Around 1.6million people have turned to the jabs in the UK over roughly a 12-month period to help them lose weight.
The Medicines and Healthcare products Regulatory Agency (MHRA) has now issued a new update for patients and doctors to be aware of a possible side effect that could be severe. And it advised anyone taking GLP-1 medication, such as Ozempic, Wegovy and Mounjaro, to seek medical help immediately if they develop it.
They said they should look out for extreme pain in the stomach and back that does not go away. This could be a sign of acute pancreatitis, where the pancreas, a small organ which sits behind the stomach, can become inflamed and swollen.
Most people with the condition will usually start to feel better within about a week and have no further problems, but some can develop more severe complications, the NHS says.
The MRHA announced on Friday it had updated the product information for healthcare professionals and patients, including those taking the medication to lose weight, to make sure they knew 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.”