Independent UK medicine guidance
Mounjaro and pancreatitis: warning signs and facts
Acute pancreatitis is an uncommon but serious Mounjaro side effect, and in January 2026 the MHRA strengthened its warnings after rare reports of necrotising and fatal cases. This guide explains the warning symptoms, exactly what to do if they occur, and what the numbers actually show, without hype in either direction.
The warning sign: severe, persistent pain in your abdomen, which may spread through to your back, with or without nausea or vomiting. If this happens: stop using Mounjaro and get urgent medical help, via NHS 111, or 999 / A&E if you are acutely very unwell. Do not take another dose while you are being assessed, and do not restart if pancreatitis is confirmed.
What is pancreatitis?
Pancreatitis is inflammation of the pancreas, the organ behind your stomach that produces digestive enzymes and hormones including insulin. Acute pancreatitis comes on suddenly and needs hospital assessment. Most people recover, but severe cases can be life-threatening, which is why the warning symptoms should never be waited out at home.
How common is it on Mounjaro?
Warning symptoms: act on these
- Severe pain in the upper or central abdomen that does not settle
- Pain that spreads through to your back
- Pain that may ease slightly when leaning forwards
- Nausea or vomiting alongside the pain, though these are not always present
- Feeling very unwell, feverish or unable to get comfortable
If these symptoms occur: stop Mounjaro and seek urgent medical help. Contact NHS 111, or call 999 or go to A&E if someone is acutely very unwell. Tell the clinicians you use tirzepatide and when your last injection was.
How is this different from ordinary digestive side effects?
Common and usually manageable
Nausea, some abdominal discomfort, bloating, wind and changes in bowel habit are very common, tend to appear around dose changes, and usually ease over time. They are covered in our nausea and vomiting guide.
Not ordinary: get assessed
Severe, persistent pain, especially spreading to the back, is not a normal adjustment symptom. It cannot be diagnosed online, and it is also how gallbladder disease can present. Both need urgent clinical assessment.
Who may be at higher risk?
- A previous episode of pancreatitis: tell your prescriber before starting or continuing treatment
- Gallstones, which are themselves a common cause of pancreatitis
- High alcohol intake
- Very high triglyceride levels
Your prescriber weighs these factors when deciding whether Mounjaro is suitable. Never assume a symptom is “just the injection” if you have a history of pancreatic or gallbladder disease.
What happens if pancreatitis is confirmed?
Acute pancreatitis is usually managed in hospital with fluids, pain relief and monitoring while the cause is investigated. If pancreatitis is confirmed while you are using Mounjaro, the medicine should not be restarted. Your clinical team will discuss what this means for your ongoing weight management or diabetes care; there are alternative approaches, and stopping one medicine is not the end of treatment options.
Raised amylase or lipase is not the same as pancreatitis
Blood tests sometimes show raised levels of amylase and lipase, two enzymes made by the pancreas, in people taking GLP-1 and GIP/GLP-1 medicines. The Mounjaro SmPC records this as a laboratory finding in its own right, separate from acute pancreatitis. A raised amylase or lipase result on its own does not predict acute pancreatitis and is not a diagnosis of it. Pancreatitis is diagnosed on the combination of symptoms, clinical examination and tests together, which is why the advice on this page is built around the symptom, not a number.
Evidence update, September 2026: pancreatic enzyme figures in the revised SmPC
On 8 September 2026 the electronic medicines compendium (eMC) published a revised Mounjaro Summary of Product Characteristics with a text revision date of 29 August 2026. It adds safety results from SURPASS-CVOT, a large trial that compared tirzepatide with dulaglutide, another injectable diabetes medicine, in adults with type 2 diabetes and established cardiovascular disease. The enzyme figures reported are:
- At month 36, mean pancreatic amylase was 29% higher than at the start of treatment
- At month 36, mean lipase was 28% higher than at the start of treatment
- Gallstones, which are themselves a common cause of pancreatitis, were reported in 2.4% of participants
These are average laboratory changes across a study population, not a count of pancreatitis cases. They do not change the uncommon frequency band for acute pancreatitis, the January 2026 MHRA warning, or the emergency advice at the top of this page.
Source: Mounjaro Summary of Product Characteristics (eMC), text revised 29 August 2026, sections 4.4 and 4.8
Reporting suspected side effects
Suspected side effects, including suspected pancreatitis, can be reported to the MHRA Yellow Card scheme by patients, carers and professionals. A report does not prove the medicine caused the event and the scheme cannot give medical advice, so seek care separately when needed.
Common questions
What does pancreatitis pain feel like on Mounjaro?
The official warning describes severe, persistent pain in the abdomen that may spread through to your back, with or without nausea or vomiting. It cannot be diagnosed online. Stop using Mounjaro and seek urgent medical help if these symptoms occur.
How common is pancreatitis with Mounjaro?
Acute pancreatitis is listed as uncommon, meaning it may affect up to 1 in 100 people. In January 2026 the MHRA strengthened its warnings for GLP-1 and GIP/GLP-1 medicines after rare reports of necrotising and fatal cases. Most people will not develop pancreatitis, but the warning symptoms must be acted on immediately.
My blood test showed raised amylase or lipase. Do I have pancreatitis?
Not on that result alone. Raised pancreatic enzymes are a recognised laboratory finding with GLP-1 and GIP/GLP-1 medicines and the SmPC lists them separately from pancreatitis. A raised amylase or lipase does not predict acute pancreatitis and is not a diagnosis of it. Your clinician will interpret the result alongside your symptoms and examination. If you have severe, persistent abdominal pain that may spread to your back, stop Mounjaro and seek urgent help whatever your blood results show.
Can I restart Mounjaro after pancreatitis?
No. If pancreatitis is confirmed, Mounjaro should not be restarted. Your clinical team will discuss alternative approaches to your weight management or diabetes care.
Related guides
Primary sources: MHRA Drug Safety Update, January 2026 • Mounjaro Patient Information Leaflet (eMC) • Mounjaro Summary of Product Characteristics (eMC) • NHS: acute pancreatitis
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Sources referenced on this page
Linked from the text above:
- Mounjaro Summary of Product Characteristics (eMC), text revised 29 August 2026, sections 4.4 and 4.8 www.medicines.org.uk
- MHRA Drug Safety Update, January 2026 www.gov.uk
- Mounjaro Patient Information Leaflet (eMC) www.medicines.org.uk
- NHS: acute pancreatitis www.nhs.uk
Standing primary references for every Monj page:
- Mounjaro (tirzepatide) Summary of Product Characteristics and Patient Information Leaflet, electronic medicines compendium
- MHRA Drug Safety Update: GLP-1 receptor agonists
- NICE TA1026: tirzepatide for managing overweight and obesity
- General Pharmaceutical Council register of pharmacies
- MHRA Yellow Card scheme
