Gallstones are a recognised side effect of Mounjaro, particularly in people using tirzepatide for weight management. The risk has been seen in clinical trials, and the UK product information reports that acute gallbladder events were positively correlated with weight reduction. This means both the medicine and the weight loss that happens during treatment may be relevant when looking at gallbladder problems.
The important thing is knowing what symptoms to look out for and what to do if you already have gallstones. This guide explains the possible link between Mounjaro and gallstones, the symptoms that need attention, when to seek urgent help, and what you can discuss with your prescriber.
Key things to know
- Gallstones, also called cholelithiasis, are a listed common side effect of Mounjaro. Gallbladder inflammation, called cholecystitis, is also listed as common.
- In pooled weight management studies, acute gallbladder disease was reported in 2.0% of people taking tirzepatide compared with 1.6% of people taking placebo.
- Gallbladder problems can also occur during weight loss itself. The Mounjaro product information found that acute gallbladder events were positively correlated with weight reduction.
- Having gallstones does not automatically mean that you cannot take Mounjaro. Your prescriber should consider your individual medical history and symptoms.
- Gallstone pain is often felt in the upper right side or middle of the abdomen and can last from more than 30 minutes to several hours.
- Gallstones can sometimes cause complications such as gallbladder inflammation, bile duct blockage or pancreatitis, so severe or persistent symptoms should not be ignored.
Does Mounjaro Actually Cause Gallstones?
Gallstones are a recognised adverse reaction to Mounjaro, so the link should not be dismissed. In the current UK product information, cholelithiasis and cholecystitis are listed as common adverse reactions.
In pooled weight management studies, gallstones were reported in 1.1% of people taking tirzepatide and 1.0% of people taking placebo. Acute gallbladder disease was reported in 2.0% and 1.6%, respectively.
The figures show that gallbladder problems can occur during treatment, but they also show that these events are not limited to people taking Mounjaro. Weight loss itself is also associated with gallstone risk, and the Mounjaro product information found that acute gallbladder events were positively correlated with weight reduction.
So it is more accurate to say that Mounjaro treatment and weight loss can both be relevant to gallbladder risk, rather than saying that Mounjaro directly causes every case of gallstones.
Why Can Gallstones Happen During Weight Loss?
The exact reason gallbladder problems occur during Mounjaro treatment is not always straightforward. Weight loss is a known risk factor for gallstones, and gallbladder events in Mounjaro weight management studies were associated with the amount of weight reduction.
Rapid weight loss can increase gallstone risk
Losing weight quickly can increase the chance of developing gallstones. This is not unique to Mounjaro. Rapid weight loss can also increase gallstone risk with other weight loss methods, including weight loss surgery.
For this reason, it is better to follow your prescribed treatment plan rather than trying to lose weight as quickly as possible.
Eating much less can also change your usual eating pattern
Mounjaro can reduce appetite, so some people eat much smaller meals than they did before treatment. Your gallbladder stores bile, which is released into the digestive system when you eat.
A large change in your normal eating pattern may affect how your gallbladder empties. However, it is too simple to say that eating less directly causes gallstones. Gallstone formation has several possible risk factors, including weight loss, obesity and other health factors.
Why this matters
Gallstones do not always cause symptoms. Some people have them without knowing they are there. Others may develop episodes of pain if a stone blocks a bile duct.
Gallstones can also lead to complications such as cholecystitis or pancreatitis if they cause a blockage. This is why new or severe abdominal pain should not automatically be assumed to be a normal Mounjaro side effect.
Can You Take Mounjaro If You Already Have Gallstones?
Having gallstones does not automatically mean that you cannot take Mounjaro. Gallstones are not listed as a contraindication in the current UK product information. The listed contraindication is hypersensitivity to tirzepatide or one of its excipients.
However, tell your prescriber if you already have gallstones or have had gallbladder problems in the past. They can consider your symptoms, medical history and overall treatment plan before deciding whether Mounjaro is suitable.
It is particularly useful to tell them:
| What to disclose | Why it matters |
|---|---|
| Whether your gallstones cause symptoms | Symptomatic gallstones need a different approach from gallstones found by chance |
| Whether you have had biliary colic or cholecystitis | Previous gallbladder problems are important when reviewing your history |
| Whether you have had pancreatitis | Tirzepatide should be used with caution in people with a history of pancreatitis |
| Whether gallbladder surgery has been discussed | Your treatment plan may need to take planned surgery into account |
| How quickly you are losing weight | Weight reduction is associated with gallbladder events during Mounjaro treatment |
The current Mounjaro product information advises caution in people with a history of pancreatitis and says patients should seek immediate medical attention if they develop symptoms of acute pancreatitis.
Gallbladder Symptoms: What to Look For
Gallstones do not always cause symptoms. When they do, the pain can be quite different from ordinary indigestion.
Biliary colic, the classic pattern
- Pain in the middle or upper right side of the abdomen
- Pain that can be severe and constant
- Pain that lasts longer than 30 minutes and may continue for several hours
- Feeling sick or being sick
- Pain that may occur after eating, although it is not always linked to a particular food
- Pain that may spread to other areas, depending on what is causing it
NHS guidance advises getting urgent medical advice if abdominal pain lasts longer than 30 minutes.
What suggests something more serious?
Severe or persistent abdominal pain needs medical assessment, particularly if you also have a high temperature, repeated vomiting or feel very unwell.
Yellowing of the skin or whites of the eyes, dark urine or pale stools can be signs of a bile duct problem and need prompt medical attention.
Severe abdominal pain that spreads to the back can also be a symptom of acute pancreatitis. Gallstones are one of the common causes of acute pancreatitis.
How can you tell it apart from ordinary Mounjaro indigestion?
It is not always possible to tell the difference based on symptoms alone.
Mounjaro can cause gastrointestinal side effects such as indigestion, abdominal pain, nausea, vomiting and constipation. Gallstones can also cause abdominal pain, nausea and vomiting.
Pain that is severe, persistent, keeps returning or is accompanied by fever or jaundice should not simply be put down to Mounjaro. If you are unsure what is causing your symptoms, speak to a healthcare professional.
When to Seek Help
Call 999 or go to A&E if you have sudden, severe abdominal pain, particularly if the pain spreads to your back, you have persistent bloating, a fast heartbeat or difficulty breathing. These can be warning signs of acute pancreatitis and need urgent assessment.
Contact NHS 111 or your GP urgently if you have abdominal pain that lasts longer than 30 minutes, particularly if you also have a high temperature, feel hot or shivery, or have repeated vomiting.
Seek urgent medical help if your skin or the whites of your eyes turn yellow. Dark urine and pale stools can also occur when there is a problem with bile flow.
Speak to your GP or prescriber if you keep getting pain in the upper right side of your abdomen, especially after meals, even if the pain eventually settles. Repeated episodes may need further investigation.
If you have symptoms that could suggest pancreatitis, do not wait for them to settle on their own. The Mounjaro product information advises patients to seek immediate medical attention for persistent, severe abdominal pain.
Reducing the Risk
You cannot completely remove the risk of gallstones during weight loss, but there are sensible steps you can take.
- Follow your prescribed dose. Do not increase your Mounjaro dose more quickly than your prescriber recommends.
- Avoid trying to lose weight as quickly as possible. Rapid weight loss can increase the risk of gallstones.
- Keep your diet balanced. Very restrictive diets can make it harder to meet your nutritional needs. If you are struggling to eat enough because of low appetite or side effects, speak to your healthcare professional.
- Stay hydrated. This is particularly important if you have vomiting or diarrhoea, as these side effects can increase the risk of dehydration.
- Pay attention to new symptoms. New or persistent upper abdominal pain should not automatically be treated as ordinary indigestion.
If Your Gallbladder Has Already Been Removed
Having your gallbladder removed does not automatically mean that Mounjaro is unsuitable. However, tell your prescriber about the surgery and any digestive symptoms you still experience.
After gallbladder removal, bile flows directly from the liver into the intestine rather than being stored in the gallbladder. Some people can experience digestive symptoms after surgery, including diarrhoea.
Gallbladder removal also does not mean that every possible bile duct problem is impossible. If you develop severe or persistent abdominal pain, jaundice, vomiting or other concerning symptoms, you should still seek medical advice.
Medical Disclaimer
This article is for general information only and does not replace individual medical advice.
Gallstones do not automatically prevent someone from taking Mounjaro, but your suitability for treatment should be assessed by your prescriber based on your medical history, symptoms and overall health.
The current UK product information lists cholelithiasis and cholecystitis as common adverse reactions to Mounjaro and advises caution in people with a history of pancreatitis.
Do not stop or change your Mounjaro dose without speaking to your prescriber.
If you develop sudden or severe abdominal pain, pain that spreads to your back, persistent vomiting, fever, yellowing of the skin or eyes, or difficulty breathing, seek urgent medical attention.
