Navigating your health journey with new medications can bring up many questions, especially when it comes to an effective weight loss and diabetes treatment like Mounjaro (active ingredient: tirzepatide). If you are using Mounjaro, or considering it, and you are also using contraception, it is crucial to understand how they might interact.

Mounjaro and similar GLP-1 agonists have become an important tool for many people managing type two diabetes or seeking to lose weight. One of the main ways these medications work is by slowing down the rate at which food and drink leave your stomach. While this helps you feel fuller for longer, it can also change the way your body absorbs other medications you take by mouth, including your contraceptive pill.

This potential interaction is significant because it could reduce the effectiveness of your oral contraception, increasing the risk of an unplanned pregnancy. The advice for Mounjaro (tirzepatide) is different from other GLP-1 agonists like semaglutide (Ozempic, Wegovy) or liraglutide (Saxenda), making it vital to have the correct information.

What is Mounjaro and How Does It Work?

Mounjaro is a prescription-only medication belonging to a class of drugs known as GLP-1 receptor agonists. It is primarily prescribed for managing type 2 diabetes or to support weight loss. One of the key ways Mounjaro works is by slowing down the speed at which food leaves your stomach, a process called delayed gastric emptying. This effect helps you feel fuller for longer, but it can also potentially interfere with how your body absorbs other oral medications, including your contraceptive pill.

Mounjaro is the brand name for the medication tirzepatide. Other GLP-1 agonists include semaglutide (known as Ozempic or Wegovy) and liraglutide (Saxenda). However, the advice regarding contraception can differ between them.

Mounjaro and the Contraceptive Pill: A Key Interaction

If you take an oral contraceptive pill (either the combined pill or the progestogen-only ‘mini-pill’), you must take extra precautions when starting Mounjaro or increasing your dose.

The delayed stomach emptying caused by Mounjaro can reduce the absorption of your contraceptive pill, potentially making it less effective. Because of this, tirzepatide works slightly differently from other GLP-1 agonists.

The official recommendation is to use a barrier method of contraception, such as condoms, in addition to your regular pill for the following periods:

• For the first four weeks after you start taking Mounjaro.
• For four weeks after every time your dose of Mounjaro is increased.

This ensures you remain protected against unplanned pregnancy while your body adjusts to the new medication or dose. Alternatively, you might consider switching to a non-oral contraceptive method altogether while using Mounjaro.

For more information on managing your treatment, visit our dedicated Mounjaro page.

What if I’m Switching from another GLP-1 Agonist to Mounjaro?

The advice remains the same even if you are already used to taking a similar medication. If you are switching to Mounjaro from any other GLP-1 agonist (like Ozempic, Wegovy, or Saxenda), you must use a barrier method like condoms for four weeks after the switch, and again for four weeks after any dose increases, while still taking your pill.

Common Side Effects: Diarrhoea, Vomiting, and Your Pill

Diarrhoea and vomiting are known potential side effects of GLP-1 agonists. These can further compromise the effectiveness of your oral contraceptive pill.

The standard advice for illness applies here:

• If you vomit within three hours of taking your contraceptive pill, it may not have been absorbed properly.
• If you experience severe diarrhoea that lasts for more than 24 hours, this can also reduce the pill’s effectiveness.

In either of these situations, you should follow the “missed pill” guidance provided in your contraceptive pill’s patient information leaflet. If diarrhoea or vomiting continues, it is wise to use condoms or consider a non-oral form of contraception.

Do Non-Oral Contraceptives Interact with Mounjaro?

If you use a non-oral method of contraception, you can be reassured. There is currently no evidence to suggest that Mounjaro or other GLP-1 agonists affect the following methods:

• The contraceptive implant
• The contraceptive injection
• The contraceptive patch
• The intrauterine device (IUD or coil)
• The vaginal ring

These methods do not rely on absorption through the stomach, so their effectiveness is not impacted by Mounjaro’s effects. No extra precautions are needed when using these contraceptives with a GLP-1 agonist. If you are considering changing your contraception, explore your options on our contraception page.

Mounjaro and Emergency Contraception

What happens if you need emergency contraception while taking Mounjaro? This is an area where more research is needed. It is not yet known for certain if GLP-1 agonists affect oral emergency contraception (the ‘morning after pill’).

The most effective form of emergency contraception is the copper IUD (coil), which is not affected by Mounjaro or by side effects like diarrhoea and vomiting.

If you require emergency contraception, it is vital that you inform the healthcare professional about all medications you are taking, including Mounjaro.

Pregnancy Planning and Mounjaro

It is important to note that GLP-1 agonists like Mounjaro are not recommended for use during pregnancy. You should use effective contraception throughout your treatment.

If you are planning to become pregnant, these medications need to be stopped for a specific period beforehand to ensure they are completely out of your system. This is known as a “washout period”.

The recommended washout periods are:

• Tirzepatide (Mounjaro): Stop at least one month before a planned pregnancy.
• Semaglutide (Ozempic, Wegovy): Stop at least two months before.
• Exenatide (Bydureon): Stop at least 12 weeks before.

If you find out you’re pregnant while taking a GLP-1 agonist, the first thing to do is get in touch with your doctor. They can give you the best advice for your specific situation. Ultimately, any choices about your contraception and family planning should always be part of a conversation with a healthcare professional you trust. They can help you weigh your options and make a plan that feels right for you.

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