Medicine regulator updates weight loss jab guidance to include pancreatitis risk

People who take weight loss jabs have been urged to stay alert to the symptoms of an infrequent but potentially severe side effect of the drugs by the medicines regulator.

The Medicines and Healthcare products Regulatory Agency (MHRA) has updated its guidance on GLP-1 receptor agonists to include the small risk of severe acute pancreatitis.

The illness is a known but infrequent side effect of these drugs, and can be particularly severe in some cases.

It causes the pancreas, the small organ behind the stomach that helps with digestion, to become swollen over a short period of time.

Most patients start to feel better within a week, but others can develop complications.

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.

A number of these drugs are now recommended on the NHS to help people lose weight, including semaglutide, under the brand name Wegovy, and tirzepatide, also known as Mounjaro.

The MHRA urged patients on these types of medication to speak to a doctor if they have symptoms such as severe, persistent stomach pain along with 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.

“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.”

Mounjaro

Research published by University College London (UCL) earlier this month estimates that 1.6 million in England, Wales and Scotland used drugs such as Wegovy and Mounjaro to help lose weight between early 2024 and early 2025.

The NHS started the roll-out of Mounjaro – dubbed the King Kong of weight-loss drugs – last March.

Over three years the health service expects to give the jabs to 240,000 people.