Like all medications, Mounjaro can cause side effects.
Common Side Effects
- Nausea: A feeling of an upset stomach, especially during the early stages of treatment.
- Diarrhoea/Vomiting: Loose stools or difficulty keeping food or fluids down.
- Constipation: Difficulty moving your bowels.
- Injection Site Reaction: Inflammation, itchiness, or redness around the injection site.
- Hypoglycemia (Low Blood Sugar): Symptoms include weakness, fatigue, or low energy. If you experience these, contact NHS 24 (111) immediately and consume a sugary snack or drink (avoid diet products).
- Headache: Sensation of tension or pressure in your head.
- Fatigue: Persistent tiredness or the urge to sleep.
- Dizziness: Feeling lightheaded or off balance.
- Stomach Discomfort: Cramping, tightening, or discomfort in the lower abdomen. Sharp, burning, or stabbing pain should prompt immediate medical attention.
- Gastric Reflux: Heartburn is a burning feeling in the chest caused by stomach acid travelling up towards the throat.
- Hair Loss: Usually due to rapid weight loss, which causes telogen effluvium (hair loss). This is usually reversible and slow and steady weight loss can prevent hair shedding.
- Gallstone Disease: Sudden, intense pain in the upper abdomen that sometimes radiates to the back, particularly between the shoulder blades. Pain tends to worsen after eating fatty foods. Other symptoms include nausea, vomiting, fever, chills and jaundice (yellowing of skin/eyes).
Serious Side Effects
If you experience any of the following, contact your healthcare provider immediately and inform them you are taking Mounjaro:
- Serious Allergic Reaction: Symptoms include significant swelling of the face, tongue, lips, or throat, wheezing, clammy skin, or loss of consciousness. Call 999 emergency services immediately if this occurs.
- Pancreatitis: Severe, continuous stomach pain lasting several days, which may radiate to the back and could include vomiting.
- Gallstone Disease: Sudden, intense pain in the upper abdomen that sometimes radiates to the back, particularly between the shoulder blades. Pain tends to worsen after eating fatty foods. Other symptoms include nausea, vomiting, fever, chills and jaundice (yellowing of skin/eyes).
- Increased Heart Rate: Feeling your heart racing while at rest.
- Change in Taste Sensitivity in Adults with Type 2 Diabetes: Anything ranging from a metallic or bitter taste to a general alteration in how foods taste, sometimes making previously favourite foods less enjoyable.
- Abnormal Touch Sensitivity in Adults with Type 2 Diabetes: A touch-based disorder that can result in feelings of pain, itchiness, tingling, shock, burning and other uncomfortable sensations in the skin.
Less Common Side Effects
Mounjaro may contribute to:
- Severe Allergic Reactions/Anaphylaxis;
- Pancreatitis and Gallstone Disease;
- Change in Taste and Touch Sensitivities;
- Increased Heart Rate.
Though uncommon, they require immediate medical attention.
If you develop severe abdominal pain or signs of an allergic reaction, such as difficulty breathing, rash, or swelling of the face, lips, or tongue, seek in-person medical help immediately.
Please refer to the Patient Information Leaflet included with your treatment for a complete list of side effects and detailed information.