Weight loss jab users have been urged to stay alert to potentially fatal side effects of the increasingly-popular method of keeping the pounds off. Product information for the GLP-1 medications marketed by Ozempic, Wegovy, Mounjaro and others has been updated to include a “small risk of severe acute pancreatitis”. The painful condition causes the pancreas – a small organ behind the stomach that helps with digestion – to become inflamed over a short period of time. Symptoms can include extreme pain in the stomach and back, fever and vomiting. While some patients will start feeling better within a week, others can develop fatal complications including necrosis, where pancreas tissue begins to die, leading to sepsis and organ failure.
Susan McGowan, the first UK death officially linked to tirzepatide, or Mounjaro, suffered multiple organ failure, septic shock and pancreatis after two low-dose injections of the medication in September 2024, with the treatment cited as a “contributing factor” to her passing. Around 1.6 million people across England and Wales used weight loss drugs including Mounjaro and Wegovy, which are available on the NHS, between early 2024 and 2025, according to research from University College London (UCL).
The GLP-1 receptor agonists work by mimicking the hormone GLP-1 to regulate blood sugar and insulin levels and were initially developed as a treatment for type 2 diabetes.
While a number of the drugs, including Mounjaro, are recommended on the NHS to help people lose weight, the Medicines and Healthcare products Regulatory Agency (MHRA) has urged patients to see a doctor if they experience symptoms including severe, persistent stomac pain, nausea and vomiting.
Dr Alison Cave, chief safety officer at the MHRA, 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,” she added.
“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 to speak to a healthcare professional and report it via our Yellow Card Scheme.”
