FDA Approves Tirzepatide (Mounjaro) to Treat Type 2 Diabetes

When the FDA approves a medication for a common health condition, it’s usually exciting news. This is because it can offer a new treatment option for millions of people. This is especially true when it comes to new medications that can treat Type 2 diabetes, a health condition that affects about 30 million people in the U.S.

The May 2022 FDA approval of tirzepatide (Mounjaro) is no exception to this excitement. This medication is the first in a new class of diabetes medications. Its clinical trials also suggest it can help lower hemoglobin A1C (HbA1C or A1C) more than other medications to which it was compared.

Read on to learn about tirzepatide: how it works, how to use it, and when you can expect it to be available in pharmacies.

What is tirzepatide?

Tirzepatide is a brand new type of medication approved to treat Type 2 diabetes in adults. It’s known as a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist. GLP-1 agonists, like semaglutide (Ozempic, Rybelsus), are already available. But this is the first dual GIP/GLP-1 receptor agonist.

Tirzepatide is an injectable medication. But it’s not a form of insulin. As we’ll discuss below, it can help lower your A1C and may also help you lose weight. It’s recommended to combine tirzepatide with a healthy diet and exercise for best results.

How is tirzepatide dosed?

Tizepatide is an injection you give to yourself once a week. It can be injected beneath the skin of your belly, upper arm, or thigh. Just be sure to change the area you inject with every dose to prevent skin irritation. You can use tirzepatide at any time of the day, with or without food.

Tirzepatide comes in in six different strengths, each as an individual single-dose pen:

• 2.5 mg/0.5 mL

• 5 mg/0.5 mL

• 7.5 mg/0.5 mL

• 10 mg/0.5 mL

• 12.5 mg/0.5 mL

• 15 mg/0.5 mL

It’s recommended to start with the lowest strength (2.5 mg per week). After 4 weeks, your dose will likely be raised to 5 mg once a week. After that, your dose can be raised by an additional 2.5 mg every 4 weeks until your blood sugar is well-controlled. The maximum dose you should use is 15 mg once a week.

How effective is tirzepatide?

Tirzepatide was studied in five phase 3 clinical trials (the last step before a manufacturer seeks FDA approval). These are known as the SURPASS trials. Overall, people using tirzepatide had about a 2% reduction in their A1C levels. Study participants also lost between 12 and 25 pounds during these studies.

The first clinical trial (SURPASS-1) compared three strengths of tirzepatide to placebo (an injection with no medication in it) over a 40-week period (a little more than 9 months). About 90% of those using tirzepatide were able to get their A1C under 7% (a typical goal for people with diabetes). This was compared to 20% of those using placebo.

In addition, between 31% and 52% of people using tirzepatide were able to drop their A1C to less than 5.7%, compared to 1% of those using placebo. An A1C of 5.7% is considered a normal level for people without diabetes.

What are the known side effects of tirzepatide?

Tirzepatide’s common side effects are mainly related to the stomach and intestines:

• Nausea

• Diarrhea

• Lower appetite

• Vomiting

• Constipation

• Upset stomach

• Stomach pain

Starting with the lowest strength of tirzepatide and raising the dose slowly helps to minimize these side effects. If you have gastroparesis (delayed stomach emptying), you shouldn’t use tirzepatide, as it can worsen symptoms of this condition.

Tirzepatide has a boxed warning (the strictest warning the FDA can give a medication) for thyroid C-cell tumors. These tumors were only seen in animal studies of the medication. Researchers aren’t sure if this can happen in humans too. But to be cautious, tirzepatide isn’t recommended for people with a personal or family history of thyroid cancer.

Medications that mimic GLP-1, like tirzepatide, can cause acute pancreatitis (swelling of the pancreas). In rare cases, this can be fatal. If you experience sudden and severe abdominal pain and vomiting, contact your healthcare provider immediately. These could be symptoms of pancreatitis.

While unlikely, tirzepatide can cause dangerously low blood sugar (hypoglycemia). This is more likely to happen if you also use insulin or medications that cause your body to release insulin, like sulfonylureas. Some symptoms of hypoglycemia include shakiness, dizziness, and sweating.

These aren't the only side effects of tirzepatide. Be sure to discuss all the risks of this medication with your healthcare provider before starting it.

Does tirzepatide interact with other medications?

It can. Because tirzepatide slows down how quickly your stomach empties, it can affect how well some medications are absorbed. This can be problematic for medications that have a narrow therapeutic index (NTI). This means a small change in dose or absorption can cause a big change in your response to the medication. One example of an NTI medication is the blood thinner warfarin (Coumadin, Jantoven).

You should also be cautious if you take oral birth control pills. Tirzepatide could affect how well these medications work to prevent pregnancy. It’s recommended to use a barrier method of protection, like condoms, for the first 4 weeks after starting tirzepatide or raising your dose. Non-oral birth control, like the patch or vaginal ring, shouldn’t be affected.

Make sure you provide a complete medication list to your pharmacist and healthcare provider before starting tirzepatide. They can double check for medication interactions and advise you how best to manage them.

How to save on Mounjaro

There are ways to save on Mounjaro, which is only available as a brand-name medication. GoodRx can help you find copay savings cards to save money on your prescription. If you have commercial insurance, you may be eligible to pay as little as $25 for Mounjaro using a savings card from the manufacturer.

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Written by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Reviewed by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

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