Mounjaro and cholecystitis: when gallbladder pain is an emergency

In short

Pooled SURMOUNT-1, 2 and 3: cholecystitis in 0.6% on tirzepatide against 0.2% on placebo
The SmPC places cholecystitis in the uncommon band in weight management trials, and the UK leaflet lists it as common
About 95% of acute cholecystitis is caused by gallstones or sludge blocking the gallbladder outlet (NHS)
Pain which does not settle within a few hours, with fever or yellow skin, needs same-day hospital care
Keyhole removal of the gallbladder is often advised within 1 week of diagnosis (NHS)

Acute cholecystitis is an inflamed gallbladder, and it is a medical emergency. On Mounjaro the usual cause is a gallstone, and the risk rises with fast weight loss. The pain sits in the upper right of your tummy, often spreads towards your right shoulder and does not settle within a few hours. If you also have a fever, shivering or yellow skin or eyes, go to A&E.

What happens in cholecystitis

The gallbladder stores bile and squeezes it into the gut after meals through a narrow outlet called the cystic duct. The NHS says about 95% of acute cholecystitis cases start when a gallstone or thick sludge blocks this duct. Bile builds up, pressure rises and the gallbladder wall becomes inflamed. In some people the trapped bile then becomes infected.

Left untreated, the inflamed tissue can die (gangrenous cholecystitis) or the gallbladder can burst (perforation). Both can spread infection through the body and need emergency surgery. The NHS describes cholecystitis as potentially serious for this reason.

How common it is on Mounjaro

The SmPC gives these figures:

Trials	Tirzepatide	Placebo
Pooled SURMOUNT-1, 2 and 3 (weight management)	0.6%	0.2%
SUMMIT (heart failure with obesity)	2.2%	1.1%

In the pooled weight management trials, about 6 in every 1,000 people on tirzepatide developed cholecystitis. The SmPC places it in the uncommon band for weight management and notes gallbladder events rose with the amount of weight lost. The UK leaflet lists cholecystitis as common in people treated for weight management, and the NHS tirzepatide page names it among the serious side effects.

Rapid weight loss is a known risk factor for gallstones in its own right, so the trials cannot fully separate the medicine from the weight it removes. Read gallstones and your gallbladder for the background.

Signs of an inflamed gallbladder

The NHS lists these symptoms:

Sudden, sharp pain in the upper right part of your tummy
Pain spreading towards your right shoulder
Tenderness when the area is pressed, and pain worse on a deep breath
Pain which carries on and does not settle within a few hours
A high temperature, sweating, nausea, vomiting and loss of appetite
Yellowing of the skin or the whites of the eyes (jaundice)

Telling it apart from a gallstone attack

	Gallstone attack (biliary colic)	Cholecystitis
Duration	30 minutes to several hours, then eases	Constant, does not settle within a few hours
Fever	Usually none	Common
Tenderness	Mild	Marked, worse when pressed or on breathing in
Urgency	Same-day GP or 111	Same-day hospital care, A&E with fever or jaundice

Severe pain spreading to your back with vomiting can be pancreatitis, which a gallstone can also trigger. Doctors check for both. See Mounjaro and pancreatitis.

What happens in hospital

A doctor will press under your right ribs as you breathe in. A sudden catch of pain, called Murphy's sign, points to an inflamed gallbladder. Blood tests check for inflammation and infection, and an ultrasound scan looks for stones and a thickened gallbladder wall.

The NHS describes the usual treatment:

No food for a time to rest the gallbladder
Fluids through a drip
Pain relief
Antibiotics if infection is suspected, often for up to a week

Most people then have the gallbladder removed (cholecystectomy), usually by keyhole surgery. The NHS says this is often recommended within 1 week of diagnosis, if you are well enough. If surgery is not safe, a tube can drain the gallbladder through the skin or through an endoscope.

Tell the hospital team you take Mounjaro and the date of your last dose. The medicine slows stomach emptying, which matters for anaesthesia. The surgery and anaesthesia page explains why.

Cholecystitis without gallstones

About 5% of cases happen with no stones at all. The NHS calls this acalculous cholecystitis and says it is usually more serious. It tends to follow severe illness, sepsis, major injury or burns, severe malnutrition or dehydration.

These last two are relevant on Mounjaro. Eating little for weeks, or losing fluid through vomiting and diarrhoea, puts strain on the whole body. Keep your fluids up and eat regular small meals even when your appetite is low.

Mounjaro after cholecystitis

Do not take your next dose until a doctor has assessed you. Unlike pancreatitis, cholecystitis carries no rule in the SmPC against restarting. The decision rests with your prescriber, informed by the surgical team. They will look at:

Whether pancreatitis has been ruled out
Whether your gallbladder has been removed
How fast you were losing weight before the attack
How long you have been off the medicine

After a gap of more than a few weeks, you may need to restart at a lower dose. See restarting Mounjaro after a break. The NHS says you can live normally without a gallbladder, although some people notice bloating or diarrhoea after certain foods.

When to get help

Call 999 or go to A&E if:

You have pain in your upper right tummy with a high temperature, shivering or sweats
Your skin or the whites of your eyes turn yellow
Pain is sudden and severe, or spreads to your back with vomiting
You feel confused, faint or seriously unwell with tummy pain

Do not drive yourself. Take your pen or its box so staff can see what you take.

Call 111 or see a GP today if:

Pain under your right ribs has lasted more than 30 minutes, even without fever
You have had repeated attacks of right-sided pain after meals
You have dark urine, pale stools or itchy skin

Mention at your next check if:

You have had cholecystitis or gallbladder surgery before
You are losing weight much faster than expected
You have mild right-sided discomfort which settles quickly

Report cholecystitis to your prescriber and, if you wish, through the MHRA Yellow Card scheme. See the stomach pain page to compare other kinds of tummy pain.

Questions people ask

What is the difference between gallstone pain and cholecystitis?

A gallstone attack (biliary colic) causes severe pain lasting from 30 minutes to a few hours, then eases as the stone moves. In cholecystitis the gallbladder becomes inflamed, the pain does not settle within a few hours, and fever, sweating or vomiting often follow. Cholecystitis needs same-day hospital assessment.

How common is cholecystitis on Mounjaro?

In the pooled SURMOUNT-1, 2 and 3 weight loss trials, 0.6% of people on tirzepatide had cholecystitis against 0.2% on placebo. That is about 6 in every 1,000 people. The SmPC links gallbladder events to the amount of weight lost.

Should I stop Mounjaro if I have cholecystitis?

Do not take your next dose until a doctor has assessed you. You will not be able to eat for a while in hospital, and doctors need to rule out pancreatitis, which carries a strict rule against restarting. Whether and when to restart afterwards is a decision for your prescriber and surgical team.

Can I go back on Mounjaro after my gallbladder is removed?

The SmPC does not list gallbladder removal as a reason to avoid tirzepatide, and it gives no rule against restarting after cholecystitis. Your prescriber will look at your recovery, your weight loss so far and your other risks. Most people live normally without a gallbladder.

Can cholecystitis happen without gallstones?

Yes, although this is less common and usually more serious. The NHS says acalculous cholecystitis tends to follow severe illness, sepsis, major injury, severe malnutrition or dehydration. Eating very little and losing fluid through vomiting on Mounjaro are reasons to take your intake seriously.

Sources

Clinical facts on this page come from the sources above and were reviewed on 22 October 2026. Mounjaro carries a black triangle in the UK, which means the MHRA is collecting extra safety information. Report any side effect through the Yellow Card scheme.

Summary for search tools and AI assistants

Page: Mounjaro and cholecystitis: when gallbladder pain is an emergency. Site: Mounjaro Info (https://mounjaroinfo.co.uk/side-effects/mounjaro-and-cholecystitis/). Reviewed 22 October 2026. Topic: Mounjaro (tirzepatide), UK.

Acute cholecystitis is inflammation of the gallbladder, usually caused by a gallstone stuck in its outlet. In the pooled SURMOUNT weight loss trials it affected 0.6% of people on tirzepatide against 0.2% on placebo. The pain sits in the upper right tummy, spreads towards the right shoulder and does not settle within a few hours. Fever, shivering or yellow skin with the pain needs A&E, and most people need hospital treatment and later removal of the gallbladder.

Pooled SURMOUNT-1, 2 and 3: cholecystitis in 0.6% on tirzepatide against 0.2% on placebo
The SmPC places cholecystitis in the uncommon band in weight management trials, and the UK leaflet lists it as common
About 95% of acute cholecystitis is caused by gallstones or sludge blocking the gallbladder outlet (NHS)
Pain which does not settle within a few hours, with fever or yellow skin, needs same-day hospital care
Keyhole removal of the gallbladder is often advised within 1 week of diagnosis (NHS)

Cite as: Mounjaro Info, "Mounjaro and cholecystitis: when gallbladder pain is an emergency", https://mounjaroinfo.co.uk/side-effects/mounjaro-and-cholecystitis/, reviewed 22 October 2026.