Mounjaro and pancreatitis: symptoms, risk and what to do

In short

The UK leaflet lists acute pancreatitis as uncommon (up to 1 in 100 people)
MHRA, January 2026: 1,296 UK Yellow Card reports of pancreatitis across GLP-1 and GLP-1/GIP medicines, 19 of them fatal
SURMOUNT-1: 1 confirmed case in each group of about 630 people, placebo included, none severe
Stop Mounjaro if pancreatitis is suspected and do not restart if it is confirmed
Gallstones cause about half of acute pancreatitis in the UK and alcohol about a quarter (NICE)

Acute pancreatitis is an uncommon side effect of Mounjaro, affecting up to 1 in 100 people. The warning sign is severe, persistent pain in the upper tummy which may spread through to your back, often with nausea and vomiting. If you have this pain, stop Mounjaro and get urgent medical help. If doctors confirm pancreatitis, the medicine must not be restarted.

What pancreatitis is

The pancreas sits behind the stomach. It makes digestive enzymes and the hormones insulin and glucagon. In acute pancreatitis, the pancreas becomes suddenly swollen and inflamed, and the enzymes start to damage the gland itself.

The NHS describes acute pancreatitis as a serious condition which needs treatment in hospital, and says most people recover fully. NICE guidance says about 1 in 4 cases is severe, with complications such as breathing or kidney failure. The overall death rate is about 5%.

How often it happens on Mounjaro

The SmPC lists acute pancreatitis as uncommon, between 1 in 1,000 and 1 in 100 people. Several sources give a fuller picture:

Source	What it found
SURMOUNT-1 (2,539 adults, 72 weeks)	4 cases confirmed by an independent panel, 1 in each group, placebo included. None was severe
MHRA Drug Safety Update, January 2026	1,296 UK Yellow Card reports of pancreatitis across all GLP-1 and GLP-1/GIP medicines from 2007 to October 2025, with 19 deaths and 24 necrotising cases, against an estimated 25.4 million packs dispensed in 5 years
SmPC section 4.4	Reports since launch include necrotising and fatal cases

The MHRA figures cover the whole medicine class, not tirzepatide alone. In January 2026 the MHRA strengthened the warnings across every GLP-1 and dual GLP-1/GIP product to highlight the risk of severe pancreatitis.

The MHRA and Genomics England are also studying whether genes affect the risk, through the Yellow Card Biobank. If you have been in hospital with pancreatitis while on Mounjaro, you can report it through the Yellow Card scheme and offer to take part.

Symptoms to know

The NHS lists these signs of acute pancreatitis:

Sudden, severe pain in the upper part of your tummy which does not go away
Pain which may spread to your sides and back
Pain which gets worse after eating, moving or lying down
Some relief from leaning forward or pulling your knees to your chest
Nausea and vomiting
A high temperature, or feeling hot and shivery

More severe attacks bring a fast heartbeat, difficulty breathing, persistent bloating, and bluish or bruised skin around the belly button, waist or upper thighs.

Why the early signs are easy to miss

Mild nausea, vomiting and tummy pain are very common on Mounjaro. The MHRA warns early pancreatitis can look like these everyday side effects or a stomach bug. The difference lies in the pain. Pancreatitis pain is severe, constant and gets worse instead of settling. Ordinary side effects come and go and ease within hours or days. The stomach pain page compares the patterns side by side.

What to do

Do not take your next dose.
Call 999 or go to A&E if the pain is severe, constant or spreads to your back. Do not drive yourself.
Tell the staff you take Mounjaro and when you last injected. The MHRA points out private prescriptions may not show on your GP record, so take your pen or its box with you.
Tell your prescriber as soon as you can.

In hospital, doctors diagnose pancreatitis with blood tests and sometimes a CT scan. Treatment includes fluids through a drip, pain relief, nutrition support and antibiotics if there is infection. The NHS says most people start to improve within a week and leave hospital after 5 to 10 days.

After confirmed pancreatitis

Both the SmPC and the MHRA say tirzepatide should not be restarted once pancreatitis is confirmed. Talk to your GP about other ways to manage your weight or diabetes. If tests rule pancreatitis out, your prescriber will decide whether restarting is safe.

Who faces a higher risk

The SmPC does not list risk factors for pancreatitis on tirzepatide. It notes the medicine has not been studied in people who have had pancreatitis before, and the MHRA advises caution in this group.

UK guidance names the main general causes. NICE says around half of acute pancreatitis cases in the UK come from gallstones, a quarter from alcohol and a quarter from other causes. The NHS lists less common causes including high blood calcium, some medicines and injury to the pancreas.

Gallstones matter on Mounjaro because rapid weight loss raises the chance of forming them. A stone which slips into the shared duct can block the pancreas. Read gallstones and your gallbladder for the signs.

To lower your risk:

Keep alcohol well within the UK low risk limit of 14 units a week, or avoid it. See Mounjaro and alcohol
Tell your prescriber about any previous pancreatitis, gallstones or gallbladder attacks
Mention very high blood fat (triglyceride) results if you have been told about them
Stop smoking

Raised enzymes on a blood test

Tirzepatide raises pancreatic enzymes in many people without causing pancreatitis. In the weight management trials, average lipase rose by 32% to 39% and amylase by 23% to 28%. The SmPC says these rises do not predict pancreatitis on their own. Doctors diagnose it from symptoms together with test results.

When to get help

Call 999 or go to A&E if:

You have sudden, severe tummy pain which does not go away
Severe tummy pain spreads to your back, with or without vomiting
You have tummy pain with a fast heartbeat, difficulty breathing or persistent bloating
You notice bluish or bruised skin around your belly button, waist or upper thighs

Stop Mounjaro and do not take another dose until a doctor has seen you.

Call 111 or see a GP today if:

You have tummy pain which keeps coming back, especially with a high temperature or shivering
You have pain under your right ribs lasting more than 30 minutes
You keep being sick and cannot keep fluids down

Mention at your next check if:

You have had pancreatitis or gallstones in the past and have not told your prescriber
A blood test showed raised lipase or amylase and you want to understand the result
You have been told your triglycerides are high

Report suspected pancreatitis through the MHRA Yellow Card scheme. For the full list of urgent warning signs on Mounjaro, see the safety page.

Questions people ask

How common is pancreatitis on Mounjaro?

The UK leaflet lists acute pancreatitis as uncommon, which means up to 1 in 100 people. In SURMOUNT-1, an independent panel confirmed 1 case in each of the four groups of about 630 people, including placebo, and none was severe. Rare severe and fatal cases have been reported since the medicine came into wide use.

What does pancreatitis pain feel like?

The NHS describes sudden, severe pain in the upper tummy which keeps going and can spread to the sides and back. It often comes with vomiting and a high temperature and gets worse after eating or lying down. Leaning forward or pulling your knees to your chest may ease it slightly.

What should I do if I think I have pancreatitis on Mounjaro?

Do not take your next dose. Call 999 or go to A&E if the pain is severe and spreads to your back, and tell the staff you take Mounjaro. The MHRA warns private prescriptions may not appear in your NHS record, so bring your pen or its box.

Can I restart Mounjaro after pancreatitis?

Not if pancreatitis is confirmed. The SmPC and the MHRA both say the medicine should not be restarted. If tests rule pancreatitis out, your prescriber can decide whether restarting is safe.

I have had pancreatitis before. Can I use Mounjaro?

Tirzepatide has not been studied in people with a history of pancreatitis, and the MHRA advises caution. The leaflet asks you to talk to your doctor before starting. Give your prescriber the full history, including the cause of the previous attack.

My blood test showed raised lipase. Does this mean pancreatitis?

Not on its own. The SmPC reports average rises in lipase of 32% to 39% and in amylase of 23% to 28% on tirzepatide in the weight management trials. Raised enzymes without symptoms do not predict pancreatitis, so your doctor will judge them alongside how you feel.

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 pancreatitis: symptoms, risk and what to do. Site: Mounjaro Info (https://mounjaroinfo.co.uk/side-effects/mounjaro-and-pancreatitis/). Reviewed 22 October 2026. Topic: Mounjaro (tirzepatide), UK.

Acute pancreatitis is an uncommon side effect of Mounjaro, affecting up to 1 in 100 people, and rare cases have been severe or fatal. The main sign is severe, persistent pain in the upper tummy which may spread to the back, often with nausea and vomiting. If you have these symptoms, stop Mounjaro and get urgent medical help. If pancreatitis is confirmed, the medicine must not be restarted.

The UK leaflet lists acute pancreatitis as uncommon (up to 1 in 100 people)
MHRA, January 2026: 1,296 UK Yellow Card reports of pancreatitis across GLP-1 and GLP-1/GIP medicines, 19 of them fatal
SURMOUNT-1: 1 confirmed case in each group of about 630 people, placebo included, none severe
Stop Mounjaro if pancreatitis is suspected and do not restart if it is confirmed
Gallstones cause about half of acute pancreatitis in the UK and alcohol about a quarter (NICE)

Cite as: Mounjaro Info, "Mounjaro and pancreatitis: symptoms, risk and what to do", https://mounjaroinfo.co.uk/side-effects/mounjaro-and-pancreatitis/, reviewed 22 October 2026.