Warning: Risk of Thyroid C-Cell Tumors
In rats, Mounjaro caused thyroid tumors, including thyroid cancer. It is not known if Mounjaro will cause thyroid tumors or a type of thyroid cancer called medullary thyroid carcinoma (MTC) in humans. Tell your provider if you get a lump or swelling in your neck, hoarseness, trouble swallowing, or shortness of breath. These may be symptoms of thyroid cancer.
Do not use Mounjaro if you or any of your family have ever had 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).
What is the FDA-approved use of Mounjaro?
Mounjaro is used along with a reduced-calorie diet and increased physical activity for chronic weight management in adults with obesity or with overweight plus a weight-related condition.
Limitations of Use:
Mounjaro should not be used in combination with other tirzepatide-containing products or any other GLP-1 receptor agonists.
Who should not use Mounjaro?
Do not use Mounjaro if:
- You or any of your family have ever had a type of thyroid cancer called medullary thyroid carcinoma (MTC) or if you have Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).
- You have a known allergic reaction to tirzepatide.
How should I take Mounjaro?
Mounjaro is available as a single-dose pre-filled injector pen or as a single-dose vial with syringe and needle. Both are self-administered as a subcutaneous injection in the stomach, thigh, or upper arm once a week on the same day every week.
You can take Mounjaro with or without food. Do not change your dosing regimen or stop taking Mounjaro as prescribed without discussing with your provider first. Your healthcare provider will guide you on a treatment regimen that may include an increase in dose every four weeks.
What should I tell my healthcare provider before using Mounjaro?
Mounjaro has certain drug interactions. It’s important to tell your healthcare provider all of the medications you are currently taking, including prescription, over-the-counter medications, vitamins, and herbal and dietary supplements.
Some medications to watch out for include:
- Medications for diabetes: Medications used to treat type 1 or type 2 diabetes, including insulin or sulfonylureas (such as Amaryl or Glucotrol XL)
- Other oral medications: Mounjaro causes a delay in gastric emptying, so it can impact the absorption of medications taken by mouth. Your provider can guide you on how to schedule your medications.
- Hormonal birth control: If you are using an oral hormonal contraceptive (birth control), Mounjaro may reduce its efficacy, especially after the first dose. Switch to a non-oral contraceptive method or use a barrier method for 4 weeks after starting Mounjaro and for 4 weeks after each dose escalation, until you reach the maintenance dose.
- Other GLP-1 medications: Including Zepbound, Wegovy, Ozempic, Saxenda, Victoza, Byetta, or Bydureon. These medications should not be taken with Mounjaro.
- Other products for weight loss: Including dietary supplements.
It’s important to share your entire medical history with your provider, especially if you have or had a history of:
- Type 1 or type 2 diabetes
- Thyroid cancer
- Gastrointestinal disease
- Pancreatitis
- Kidney disease
- Diabetic retinopathy
- Depression
- Suicidal thoughts or behavior
Pregnancy and Breastfeeding:
- If you are pregnant: Mounjaro should not be used during pregnancy. Based on animal studies, there may be potential risks to an unborn baby from exposure to Mounjaro during pregnancy. There is no benefit to weight loss during pregnancy and it may cause harm to the unborn baby.
- If you are a female of reproductive potential: Mounjaro may reduce the efficacy of oral hormonal contraceptives. Switch to a non-oral contraceptive method or use a barrier method for 4 weeks after starting medication and for 4 weeks after each dose escalation until you reach a maintenance dose.
- If you are breastfeeding: It is not known if Mounjaro passes into breast milk. Talk to your provider first about the benefits and risks of using Mounjaro while breastfeeding.
Pregnancy Registry: A pregnancy exposure registry will monitor pregnancy outcomes in women exposed to Mounjaro during pregnancy. Pregnant patients exposed to Mounjaro and healthcare providers are encouraged to contact Eli Lilly and Company at 1-800-LillyRx (1-800-545-5979).
What are the most serious side effects that I or a caregiver should monitor for when taking Mounjaro?
If you are experiencing a medical emergency, call 911 or seek immediate medical attention.
These serious side effects are rare, but can occur with Mounjaro. You or a caregiver should carefully monitor for these side effects, especially during the beginning of treatment or with dose changes.
- Thyroid C-Cell Tumors: In rats, Mounjaro caused thyroid tumors, including thyroid cancer. It is unknown whether Mounjaro causes thyroid C-cell tumors in humans. Tell your provider if you get a lump or swelling in your neck, hoarseness, trouble swallowing, or shortness of breath. These may be symptoms of thyroid cancer.
- Severe Gastrointestinal Disease: Mounjaro is associated with gastrointestinal side effects, such as nausea, diarrhea, vomiting, constipation, and stomach pain. It hasn’t been studied in patients with severe gastrointestinal disease and isn’t recommended in these patients.
- Acute Kidney Injury: Gastrointestinal side effects like diarrhea, nausea, and vomiting may lead to dehydration, which could cause kidney problems. It’s important to drink plenty of water to reduce dehydration risk.
- Acute Gallbladder Disease: Mounjaro is associated with an increased chance of acute gallbladder disease. Tell your provider right away if you have pain in your upper stomach, yellowing of skin or eyes (jaundice), fever, or clay-colored stools.
- Inflammation of the Pancreas (Acute Pancreatitis): Monitor for signs of acute pancreatitis, such as severe abdominal pain that doesn’t go away, possibly radiating to the back, with or without vomiting.
- Allergic Reactions: Stop using Mounjaro immediately if you experience symptoms of a serious allergic reaction, including swelling of your face, lips, tongue, or throat, severe rash, itching, rapid heartbeat, breathing difficulties, or fainting.
- Low Blood Sugar (Hypoglycemia): Mounjaro lowers blood glucose and can cause low blood sugar in patients with type 2 diabetes who take other glucose control medications. Monitor your blood sugar and be aware of symptoms of low blood sugar such as dizziness, blurred vision, mood changes, sweating, or fast heartbeat.
- Suicidal Behavior and Ideation: Pay attention to any changes in mental health, especially sudden mood or behavior changes. Contact your healthcare provider if you notice new or worsening mental health concerns.
- Pulmonary Aspiration During Surgery: Mounjaro can delay gastric emptying, and there have been reports of pulmonary aspiration in people taking GLP-1 medications during surgeries requiring sedation. Contact your provider if you have a planned surgery.
Never Share a Pen or Needle: Sharing of pens or needles poses a risk of infection.
What are the most common side effects of Mounjaro?
- Nausea
- Diarrhea
- Vomiting
- Constipation
- Stomach pain
- Indigestion
- Injection site reactions
- Fatigue
- Allergic reactions
- Belching
- Hair loss
- Gastroesophageal reflux disease (heartburn)
You are encouraged to report any negative side effects of prescription products to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.
This information is not comprehensive. Please see the full Prescribing Information for complete safety information.