What are the side effects of Mounjaro?
Like any medication, Mounjaro can cause side effects, although not everyone will experience them.
Serious Side Effects
The serious side effects of Mounjaro can be categorised as being uncommon or rare.
Uncommon (may affect up to 1 in 100 people):
- Inflamed pancreas (acute pancreatitis) - symptoms may include severe and long-lasting pain in your stomach (the pain may move to your back). Seek immediate medical attention if you experience any of these symptoms.
Rare (may affect up to 1 in 1,000 people):
- Severe allergic reactions (anaphylactic reactions, angioedema) – seek immediate medical attention and inform your doctor straight away if you experience symptoms such as breathing problems, swelling of face, lips, tongue, and/or throat with difficulty swallowing, wheezing, fast heartbeat, pale and cold skin and feeling dizzy or weak.
Other Side Effects
The other side effects of Mounjaro can be categorised as being very common, common or uncommon.
Very Common (may affect more than 1 in 10 people):
- Nausea*
- Diarrhoea*
- Vomiting*
- Stomach (abdominal) pain
- Constipation
- Low blood sugar (hypoglycaemia) when tirzepatide is used for the treatment of type 2 diabetes with medicines that contain sulphonylurea and/or insulin. If you are using sulphonylurea or insulin, the dose may need to be lowered while you use tirzepatide. Symptoms of low blood sugar may include headache, drowsiness, weakness, dizziness, feeling hungry, confusion, irritability, fast heartbeat and sweating. Your doctor should tell you how to treat low blood sugar.
*These side effects are usually not severe and tend to subside over time as your body adjusts to the treatment.
It is important to be aware that diarrhoea or vomiting can lead to dehydration, which may be serious. Make sure to stay hydrated during your treatment and contact your GP or doctor if you experience these symptoms.
Common (may affect up to 1 in 10 people):
- Allergic reactions (hypersensitivity) – symptoms include rash, itching and eczema
- Feeling dizzy
- Low blood pressure
- Decreased appetite
- Indigestion (dyspepsia)
- Bloating of the stomach
- Burping
- Gas (flatulence)
- Reflux or heartburn (also known as gastro-oesophageal reflux disease (GORD))
- Hair loss
- Fatigue
- Injection site reactions (e.g. itching or redness)
- Increased levels of pancreatic enzymes (such as lipase and amylase) in blood
- Increased calcitonin levels in the blood
- Gallstones
- Low blood sugar (hypoglycaemia) when tirzepatide is used for type 2 diabetes with both metformin and a sodium-glucose co-transporter 2 inhibitor (another diabetes medicine). Symptoms may include headache, drowsiness, weakness, dizziness, feeling hungry, confusion, irritability, fast heartbeat and sweating.
Uncommon (may affect up to 1 in 100 people):
- Injection site pain
- Fast pulse
- Infection of the gallbladder (cholecystitis)
- Changes in sense of taste
- Changes in skin sensation
- A delay in the emptying of the stomach
- Low blood sugar (hypoglycaemia) when tirzepatide is used with metformin for type 2 diabetes. Symptoms may include headache, drowsiness, weakness, dizziness, feeling hungry, confusion, irritability, fast heartbeat and sweating.