Mounjaro is an injectable drug used to improve blood sugar levels in adults with type 2 diabetes. The active ingredient, tirzepatide, is a GLP-1 and GIP receptor agonist. This ingredient mimics the action of certain hormones in your body, which reduce your appetite and slows the digestion of food.

Like with any type of medication, Mounjaro can cause side effects. Side effects of Mounajro can include vomiting, stomach pain and diarrhoea. These effects can range from mild, once your body is used to the medication, to severe, particularly when starting Mounjaro or moving up a dose. It is important to distinguish that not everyone who uses Mounjaro will experience side effects, and some are more common than others.

For a full list of possible side effects, please read through the Patient Information Leaflet.

What are the Most Common Side Effects of Mounjaro?

The most common side effects of Mounjaro tend to affect the digestive system. These can include:

  • Nausea (feeling sick)
  • Diarrhoea
  • Decreased appetite
  • Vomiting
  • Constipation
  • Indigestion
  • Stomach pain

    • Around 1 in 10 patients will experience these effects, and they can range from fairly mild to severe. You may even notice that your side effects will get better with time, as your body adjusts to the medication; in turn, they may get worse as you move up to a higher dose.

    What are the Mild Side Effects of Mounjaro?

    Some of the reported mild side effects include:

    • Nausea or vomiting
    • Diarrhoea
    • Decreased appetite
    • Constipation
    • Stomach pain
    • Injection site reaction
    • Heartburn
    • Mild allergic reactions

      • If these side effects do not go away or start bothering you, talk with your doctor or pharmacist. They may recommend lowering your dosage, or aiming for a lower maintenance dose.

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      What are the Serious Side Effects of Mounjaro?

      Serious side effects of Mounjaro are less common but they can occur. If these occur, contact your doctor as soon as possible. The serious side effects of Mounjaro include:

      • Acute pancreatitis (inflamed pancreas) Hypoglycemia (low blood sugar)
      • Serious allergic reactions
      • Kidney problems (kidney failure)
      • Severe stomach problems and abdominal pain
      • Blurred vision, or other changes in vision
      • Gallbladder problems

        • Injection Site Reactions

        Injection site reactions is a type of side effect that can occur with the use of Mounjaro. This would present as pain, swelling, redness or skin discoloration at the site of your injection. Mounjaro can be injected in the upper arm, thigh or abdomen.

        These reactions are usually mild and will disappear on their own over time. However, if you feel that these symptoms are not going away or causing you bother, then contact your doctor or pharmacist as soon as possible.

        Allergic Reactions

        A side effect of Mounjaro can be an allergic reaction. Symptoms of a mild allergic reaction can include skin rash, itchiness and flushing of skin. Severe allergic reactions can present with swelling of the eyelids, lips, hands, feet, tongue, mouth or throat as symptoms. Severe allergic reactions are much more rare, but they are possible.

        If these symptoms occur, then contact your doctor or get medical help immediately.

        How Long do Mounjaro Side Effects Last?

        The length of time you will experience side effects when using Mounjaro can vary from person to person. Most of the common and mild effects will go away within a few days to a couple of weeks.

        You may also notice that your side effects will go away after a few days, but return when you move to a higher dose. This is a normal consequence of the dosage schedule.

        If your side effects last longer, or are more severe, speak to your doctor or pharmacist for medical advice.

        Warnings for Mounjaro

        Warnings for Mounajro include:

        • May cause thyroid tumours including thyroid cancer
        • Do not use if you have a personal or family history of a type of thyroid tumor called medullary thyroid carcinoma (MTC) or other thyroid C cell tumors.
        • Do not use if you have multiple endocrine neoplasia syndrome type 2 (MEN 2)
        • Do not use if you are allergic to Mounajro or any ingredients used in it

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        Summary

        • Like all prescription medications, some patients will experience side effects when using Mounjaro.
        • These side effects can range from mild to severe, and may be worse when you start Mounjaro, or move up to a higher dose.
        • If your side effects are severe, you should speak to your doctor or pharmacist.
        • If you experience signs of a severe allergic reaction, you should seek immediate medical attention.