Mounjaro (tirzepatide) injection is used for type 2 diabetes in adults to lower blood sugar levels (blood glucose) and A1C levels. Mounjaro is a once-weekly injection that should be used together with diet and exercise. Clinical trials for a 15 mg dose of Mounjaro for weight loss showed patients lost a mean of 20.9% of their body weight compared to 3.1% for placebo over 72 weeks. However, the FDA has not approved Mounjaro for weight loss yet.  

Mounjaro works to lower blood sugar by helping the pancreas make more insulin, lowering the amount of sugar your liver makes, and slowing the rate food passes through your body, making you feel full longer. It does this by activating the two different receptors GIP and GLP-1, which are natural incretin hormones that help regulate blood sugar levels.

Mounjaro is the first GIP/GLP-1 receptor agonist, which means it works on the glucose-dependent insulinotropic polypeptide (GIP) receptors and the glucagon-like peptide-1 (GLP-1) receptors.

This injection is not for use in people with type 1 diabetes. It is not known if this medicine can be used in people who have had pancreatitis.

Mounjaro injection became an FDA-approved medicine on May 13, 2022, to improve blood sugar (glucose) levels in adults with type 2 diabetes mellitus, when used together with diet and exercise.  Mounjaro for weight loss has received the Food and Drug Administration (FDA) Fast Track designation to speed up its path for FDA submission for treating adults with obesity or overweight with weight-related health conditions.  

Has the FDA approved Mounjaro for weight loss?

No, it is not FDA-approved for weight loss.

Although the FDA has not approved Mounjaro for weight loss yet, results from clinical trials have been positive, so it may be approved for weight loss in the future. In the Phase 3 SURMOUNT-1 72-week clinical trials, the mean Mounjaro weight loss was 15% for the 5mg dose, 19.5% for the 10mg dose, 20.9% for the 15mg dose, and 3.1% for placebo. The trial included patients who were overweight, obese, and had a weight-related health issue but excluded patients with diabetes.

Currently Mounjaro is FDA approved for adults with type 2 diabetes to decrease blood sugar levels (blood glucose) and A1C levels.

Call your doctor immediately if you have thyroid tumor symptoms, such as a lump or swelling in your neck, hoarseness, trouble swallowing, or shortness of breath. 

In studies with rats, tirzepatide and medicines that work in the same way caused thyroid tumors, including thyroid cancer. It is not known whether Mounjaro will cause thyroid tumors or a type of thyroid cancer called medullary thyroid carcinoma (MTC) in people.

You should not use this medicine if you or you have a family history of a type of thyroid cancer called medullary thyroid carcinoma (MTC) or if you have an endocrine system condition called Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).

Keep all appointments with your doctor and the laboratory. Your doctor may order certain tests to check your body's response to this medicine.

You should follow the directions on your prescription label carefully and ask your pharmacist or doctor to explain any part you do not understand. It is important to use this medicine exactly as directed. Do not take more or less of it or more often than your doctor prescribes.

Mounjaro is a pre-filled pen injected under the skin (subcutaneously). 

Mounjaro is usually given:

• once a week.
• can be given with or without meals at any time of the day. 
• may be injected into the thigh, abdomen, or upper arm. 
• you should rotate the injection site with each dose.

Your doctor will usually start you on a low dose, which will be gradually increased, but not more than once every 4 weeks.

You may change the day of the week you use this medicine as long as there is at least three days between doses.

You may give insulin in the same area as this medicine, but they should not be given right next to each other. Do not mix insulin and Mounjaro in the same injection.

Mounjaro controls type 2 diabetes but does not cure it. It may take four weeks or longer before you see the full benefit of this medicine. Continue to take this medicine even if you feel well. Do not stop taking this medicine without talking to your doctor.

For more detailed instructions with diagrams, on how to use this medicine, click here: Instructions for Mounjaro.

Usual Adult Dose for Diabetes Type 2:

Initial dose: 2.5 mg under the skin (subcutaneously) once a week.

After 4 weeks: The dosage should be increased to 5 mg subcutaneously once a week.

If additional glycemic control is needed: The dosage should be increased in 2.5 mg increments after at least 4 weeks on the current dose.

Maximum dose: 15 mg subcutaneously once a week.

Comments: The 2.5 mg dosage is for starting of treatment and is not intended for glycemic control. The day of weekly administration can be changed, if necessary, as long as the time between the 2 doses is at least 3 days (72 hours).

What strength are Mounjaro pens available as?

• 2.5 mg/0.5 mL single-dose pen
• 5 mg/0.5 mL single-dose pen
• 7.5 mg/0.5 mL single-dose pen
• 10 mg/0.5 mL single-dose pen
• 12.5 mg/0.5 mL single-dose pen
• 15 mg/0.5 mL single-dose pen.

There have been issues with Mounjaro availability with drug shortages for some strengths due to increase for the demand.

You should not use this medicine if you:

• are allergic to the tirzepatide or any ingredients contained in this medicine, click here for a full list of Mounjaro ingredients.
• have a personal or family history of medullary thyroid carcinoma (a type of thyroid cancer); or
• multiple endocrine neoplasia type 2 (tumors in your glands).

Tell your doctor if you have ever had:

• pancreas problems;
• kidney disease;
• a severe stomach problem such as problems with digesting food or slowed emptying of your stomach (gastroparesis); or
• diabetic retinopathy (a diabetes complication that affects the eyes).

Pregnancy

Tell your healthcare provider if you are pregnant, you become pregnant, or plan to become pregnant while using this medicine. It is not known if this medicine will harm your unborn baby. 

This medicine can make birth control pills less effective. Ask your doctor about other birth control options such as an injection, implant, skin patch, vaginal ring, condom, diaphragm, cervical cap, or contraceptive sponge. If you take birth control pills, you may need to use additional birth control methods for 4 weeks after starting this medicine, and for 4 weeks each time, the dose is raised.

Breastfeeding

Tell your healthcare provider if you are breastfeeding or plan to breastfeed while using this medicine. It is not known whether this tirzepatide passes into your breast milk. Talk to your healthcare provider about the best way to feed your baby while using this medicine.

Take the missed dose as soon as you remember it within 4 days after the missed dose. However, if more than 4 days have passed, skip the missed dose and continue your regular dosing schedule. Do not inject two doses within 3 days of each other.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at Poison Help If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Common Mounjaro side effects

The most common side effects include nausea, diarrhea, decreased appetite, vomiting, constipation, dyspepsia, and abdominal pain.

• nausea, diarrhea, decreased appetite, vomiting; or
• constipation, indigestion, or stomach pain.

Serious Mounjaro side effects

Stop using this medicine and get emergency medical help if you have:

• signs of an allergic reaction: hives; difficulty breathing; feeling light-headed; swelling of your face, lips, tongue, or throat; or
• pancreatitis with symptoms of severe pain in your upper stomach spreading to your back, nausea and vomiting.

Call your doctor at once if you have:

• severe stomach problems;
• eye side effects or vision changes, including blurry vision or blurred vision;
• signs of a thyroid tumor symptoms may include swelling or a lump in your neck, trouble swallowing, a hoarse voice, or if you feel short of breath;
• gallbladder problem with symptoms including chalky-colored stools, stomach pain after eating, nausea, heartburn, bloating, and severe upper stomach pain that may spread to your back;
• low blood sugar symptoms may include headache, hunger, weakness, sweating, confusion, irritability, dizziness, fast heart rate, or feeling jittery; or
• kidney problems with little or no urination, swelling in your feet or ankles, feeling tired or short of breath.

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.

Birth control pills may not work as well while receiving this medicine. Your doctor may suggest you use another form of birth control for 4 weeks after starting this medicine and for 4 weeks after each dose change.

Taking tirzepatide with other medicines to treat diabetes like insulin or sulfonylureas may increase your risk of hypoglycemia. Talk to your doctor and pharmacist about low blood sugar and how to manage it.

This list is not complete. Many other drugs may interact with this medicine, including prescription and over-the-counter medicines, vitamins, and herbal products. To check for interactions with this medicine click the link below.