Mounjaro: weighing up the risks and benefits

What Benefits Are We Hoping For?

Benefits are possibilities, not guarantees. Different people respond differently.

What Risks Are Common?

The most common side effects are digestive. These include nausea, diarrhoea, vomiting, stomach pain and constipation. Reflux, burping, sulphur burps, bloating, dry mouth and tiredness can also happen.

These are often more noticeable when starting treatment or after a dose increase, although individual responses vary.

For practical tips, read Common side effects of Mounjaro and what to do and Managing Mounjaro side effects.

Pancreatitis: What Is It?

The pancreas is an organ that helps with digestion and blood sugar control. Pancreatitis means inflammation of the pancreas. It is uncommon, but it can be serious.

Stop taking Mounjaro and seek immediate medical help if this happens. If pancreatitis is confirmed, Mounjaro should not be restarted.

This does not mean every stomach ache is pancreatitis. But severe, persistent pain is not something to wait out at home.

Gallbladder Problems

Gallstones and gallbladder inflammation can happen during weight loss itself, as well as being reported with some weight-loss medicines. The gallbladder sits under the liver and helps digest fat.

Ask for urgent advice if you have severe right-sided upper tummy pain, pain with fever, yellowing of the skin or eyes, dark urine, pale stools, or you feel very unwell.

Dehydration And Kidney Problems

Vomiting and diarrhoea can lead to dehydration. Dehydration can sometimes affect kidney function, especially in people who are older, frail, already have kidney problems, or take certain medicines.

Do not push through repeated vomiting or diarrhoea. Sip fluids, consider oral rehydration, and seek advice if you cannot keep fluids down or you are passing very little urine.

Low Blood Sugar

Mounjaro on its own is less likely to cause low blood sugar. The risk is more important if it is used with insulin or sulphonylurea tablets such as gliclazide.

If you take diabetes medication, your prescriber may need to review doses and monitoring. Symptoms of low blood sugar can include shaking, sweating, hunger, confusion, palpitations, dizziness or feeling faint.

Eyesight And Diabetes

Vision problems are not a common side effect of Mounjaro. People with diabetes may already be at risk of diabetic eye disease, and changes in blood glucose can sometimes affect vision.

Tell your prescriber if you have diabetic retinopathy or macular oedema so that appropriate monitoring can be considered. Seek urgent medical advice for sudden vision loss, a rapid deterioration in vision, dark shadows or loss of part of your visual field, whatever the cause may be.

Surgery, Anaesthetic And Sedation

Mounjaro can slow stomach emptying. This matters if you are having surgery, an endoscopy, deep sedation or an anaesthetic, because food or fluid staying in the stomach may affect safety planning.

Tell your surgical, anaesthetic or endoscopy team that you use Mounjaro. Do not stop or restart medication around a procedure without following the advice you are given.

Who Needs Extra Caution?

Mounjaro may need extra discussion, delay or specialist advice if you:

• have had pancreatitis
• have gallstones or significant gallbladder disease
• have severe digestive problems or delayed stomach emptying
• have significant kidney disease or are at high risk of dehydration
• take insulin or sulphonylurea tablets
• are pregnant or planning pregnancy—Mounjaro should not be used during pregnancy and should be stopped at least 1 month before trying to conceive
• are breastfeeding or planning to breastfeed, as this needs an individual clinical discussion
• use oral contraception or oral progesterone as part of HRT
• have an active eating disorder or are struggling to eat safely
• are due to have surgery, sedation or an endoscopy

The Wider Health Picture

Medication risks are only one part of the decision. Obesity and metabolic disease can also affect health, and Mounjaro is one of several possible approaches to treatment and support.

This is not about pressuring anyone into medication. It is about considering the likely benefits, risks, alternatives and your own preferences through shared decision making.

How To Reduce Risk