Weight-loss jabs may be behind a rise in gallbladder removals, doctors suggest.
The NHS in England carried out 80,196 gallbladder operations in 2024-25 – the highest number in the past decade and a 15 per cent increase on the previous year.
Surgeon Ahmed Ahmed, president of the British Obesity and Metabolic Specialist Society, said ‘more and more’ of his patients having these operations tell him they have taken weight loss jabs.
The medications, called GLP-1 receptor agonists, were first developed as a treatment for type 2 diabetes. They work by mimicking the hormone GLP-1 to regulate blood sugar and insulin levels.
A number of the drugs are recommended on the NHS to help people lose weight, including semaglutide, under the brand name Wegovy, and tirzepatide, also known as Mounjaro.
One side-effect is an increased risk of gallstones, which are hardened deposits of digestive fluid in the gallbladder.
But, rapid weight loss, a diet low in fibre and high in fat, and obesity can also lead to gallstones.
Mr Ahmed said: ‘We don’t know whether it’s the injections that are causing the gallstones, or is it because the injections are causing rapid weight loss, which then in turn causes the gallstones?
Surgeon Ahmed Ahmed, president of the British Obesity and Metabolic Specialist Society, said ‘more and more’ of his patients requiring gallbladder removal tell him they have taken weight loss jabs such as Mounjaro (pictured)
A graphic showing the location of the gallbladder (small sac in red on left) and pancreas (bigger organ beneath in red)
‘Clearly this area needs further research to find out if it’s causative or not.’
James Hewes, a Bristol-based consultant surgeon who also specialises in obesity and bariatric surgery, said: ‘Anecdotally, we are seeing more patients presenting with gallstones.
‘Often, it’s difficult to know if that’s related to the injection, or whether they had them originally but weren’t assessed properly beforehand.’ It comes after the medicines regulator updated its guidance on GLP-1 receptor agonists to include the small risk of severe acute pancreatitis.
The Medicines and Healthcare products Regulatory Agency said the illness is a known but infrequent side-effect of these drugs, and can be particularly extreme 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.
While most patients start to feel better within a week, others can develop complications.
According to the NHS, one of the leading causes of pancreatitis is gallstones.
Eli Lilly, which makes Mounjaro, said its patient information leaflet warns gallstones are a common side-effect when the drug is used for weight management, and may affect up to one in ten people.
It added that gallstones and gallbladder infections are uncommon when the drug is used to manage type 2 diabetes, and may impact one in 100 people.
A spokesman for Wegovy maker Novo Nordisk said GLP-1 drugs ‘are a well-established class of medicines, which have been studied rigorously in clinical trials’. According to Novo Nordisk, acute gallstone disease was reported in 1.6 per cent of patients, which led to cholecystitis, or inflammation of the gallbladder, in 0.6 per cent of patients.
‘For this reason, acute gallstone disease is listed as a ‘common’ potential adverse reaction for Wegovy in the product’s UK SMPC (product summary) and should be considered when patients are being evaluated for this medicine,’ it said.
