Please read the information below carefully if you are using Mounjaro and a Contraceptive tablet or oral HRT. If you feel this applies to you or would like to discuss further, please contact the surgery.

Many patients are now using weight loss medications like Tirzepatide (Mounjaro) or Semaglutide (Ozempic, Wegovy, Rybelsus) — either for diabetes or privately for weight loss. These medications work partly by slowing down how your stomach empties — which can affect how well other medicines (like the contraceptive pill or HRT tablets) are absorbed by your body.

GLP-1 Agonists and Oral Contraception

What should I do if I am taking the contraceptive pill and using Tirzepatide or a semaglutide:

Tirzepatide (Mounjaro):  Tirzepatide may reduce how well the contraceptive pill works. You should use a non-oral methods of contraception (e.g. coil or implant) or a barrier method (like condoms) for four weeks after starting Mounjaro and also for four weeks after increasing your dose of Tirzepatide (Mounjaro). You should also use extra protection (like condoms) if you have vomiting or diarrhoea and should follow the missed pill rules (see the patient information leaflet which comes with your pill) if you vomit within 3 hours of taking the pill or have diarrhoea for more than 24 hours.

Semaglutide (Ozempic, Wegovy, Rybelsus) and others: These do not appear to reduce the effectiveness of the pill currently however side effects like vomiting or diarrhoea can still reduce how well the pill is absorbed. Therefore you should use extra protection (like condoms) if you have vomiting or diarrhoea and follow the missed pill rules (see the patient information leaflet which comes with your pill) if you vomit within 3 hours of taking the pill or have diarrhoea for more than 24 hours.

Other GLP-1 Medications such as Exenatide, Liraglutide, Dulaglutide and Lixisenatide are currently not known to have a direct interaction with oral contraception.

Is Emergency Contraception affected if I am taking a GLP-1 medication?

We do not know yet if oral emergency contraception is affected by GLP-1 agonists. The copper IUD (Coil) is the most effective method of emergency contraception and is not affected by diarrhoea and vomiting. If you require emergency contraception, please ensure you tell the healthcare practitioner about all medication you are taking including GLP-1 agonists.

Please see further information here : Patient-information-GLP-1-agonists-and-contraception (EXTERNAL PDF LINK) which has been created by the Faculty of Sexual and Reproductive Healthcare (February 2025).

GLP-1 agonists and HRT medication

There is some concern that weight loss medications – such as Tirzepatide (Mounjaro) may reduce how well the progesterone tablets (Progesterone, Utrogestan, Norethisterone and Medroxyprogesterone Acetate)  are absorbed. This could lead to irregular bleeding and may affect the protection of your womb lining (potentially leading to an increased risk of endometrial cancer).

What are my options if I am taking oral progesterone as part of my HRT medication and also on a GLP-1 agonist?

Options are changing the oral progesterone component of HRT to

1. A Mirena Coil: which is the most ideal option as it works for 5 years as part of HRT and is also a contraception.
2. Combined HRT Patch: contains both oestrogen and progesterone and bypasses the stomach
3. Increasing the oral progesterone dose: It is currently recommended that the progesterone dose is doubled for four weeks after initiation of a GLP-1 agonist and also subsequently for four weeks after each increase in GLP-1 agonist dose.