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Updated contraception advice for Mounjaro (tirzepatide)

Medicine Safety Update

Reminder not to use GLP-1 RAs during pregnancy

Published

Summary

Our investigation into the potential for reduced effectiveness of oral contraception during initiation or dose escalations with Mounjaro (tirzepatide) has found that this association could not be ruled out.

As a precautionary measure, the Product Information (PI) and Consumer Medicines Information (CMI) for tirzepatide has been updated to include further advice for patients using oral contraceptives. Patients are advised to switch to a non-oral contraceptive or add a barrier method of contraception for 4 weeks after initiation and for 4 weeks after each dose escalation with tirzepatide.

Tirzepatide is a dual glucose-dependent insulinotropic polypeptide (GIP)/glucagon-like-peptide-1 receptor agonist (GLP-1 RA). It is approved in the treatment of type 2 diabetes mellitus (T2DM), chronic weight management and for the treatment of obstructive sleep apnoea in adults with obesity.

It belongs to the GLP-1 RA class of prescription medicines used primarily to manage T2DM and obesity.

The GLP-1 RAs currently marketed in Australia are:

None of these medicines are recommended for use during pregnancy.

Ozempic and Trulicity are both PBS subsidised in certain circumstances.

What health professionals should do

Be alert to the PI update for tirzepatide and advise patients taking oral contraceptives to switch to a non-oral contraceptive or add a barrier method of contraception for 4 weeks after initiation and for 4 weeks after each dose escalation.

Advise patients that GLP-1 RAs should not be used during pregnancy and individuals of childbearing potential are advised to use effective contraception during treatment with a GLP-1 RA.

Background

In June 2025, the United Kingdom’s Medicines and Healthcare products Regulatory Agency published guidance for GLP-1 medicines for weight loss and diabetes, including advice on contraception and pregnancy.

We conducted an independent investigation for GLP-1 RAs and the potential for reduced effectiveness of oral contraception which resulted in the tirzepatide PI update.

We will continue to monitor the safety of GLP-1 RA medicines and will take appropriate regulatory action to address safety concerns when they are identified.

Updates to Product Information

The following text was added to the existing interaction for tirzepatide and oral contraceptives:

4.5 INTERACTIONS WITH OTHER MEDICINES AND OTHER FORMS OF INTERACTIONS:

Oral contraceptives

Reduced efficacy of oral contraceptives cannot be excluded, it is therefore advised that patients using oral hormonal contraceptives switch to a non-oral contraceptive method or add a barrier method of contraception for 4 weeks after initiation and for 4 weeks after each dose escalation with Mounjaro.

Adverse events reported to us

A search of our Database of Adverse Event Notifications (DAEN) on 9 September 2025 for ‘pregnancy on oral contraceptive’ retrieved 1 case report with tirzepatide and 1 case report with semaglutide.

Further reading

Disclaimer

Medicine Safety Updates are aimed at health professionals. They are intended to provide practical information to health professionals on medicine safety, including emerging safety issues. The information in Medicine Safety Updates is necessarily general and is not intended to be a substitute for a health professional's judgment in each case, taking into account the individual circumstances of their patients. Reasonable care has been taken to ensure that the information is accurate and complete at the time of publication. The Australian Government gives no warranty that the information in this document is accurate or complete and shall not be liable for any loss whatsoever due to negligence or otherwise arising from the use of or reliance on this document.

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Medicines Safety Update is written by staff from the Pharmacovigilance Branch.

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