UK health officials warn women on Mounjaro cannot rely on the pill
So-called skinny jabs have been associated with a mini ‘baby boom’ after apparently reducing the effectiveness of the oral contraceptive pill.
Weight-loss jabs could stop the contraceptive pill working and lead to unwanted pregnancies, health officials have warned.
The UK’s medicines regulator, the MHRA, issued an alert that women taking Mounjaro should “not rely on oral contraception” and urged them to use additional “barrier” methods such as condoms, or switch to a non-oral contraceptive such as the coil.
The watchdog has received more than 40 reports of pregnancy among women on GLP-1 drugs, which have been linked to a “baby boom” and women having unexpected “Ozempic babies”.
However, only Mounjaro - the brand name for tirzepatide - appeared to reduce the effectiveness of the pill, according to the alert, not Wegovy or Ozempic, brand names for semaglutide.
Experts believe this is because Mounjaro works slightly differently from other GLP-1 drugs and therefore has a greater impact on different hormones in the body.
The MHRA said: “Mounjaro may reduce the effectiveness of oral contraceptives in those who are overweight. Therefore, those taking Mounjaro who are overweight and are using an oral form of contraception are advised to also use a non-oral form of contraception.
“This only applies to those taking Mounjaro and is especially important for the four weeks after starting Mounjaro and after any dose increase.”
GLP-1 drugs help people feel fuller by mimicking a natural hormone released after eating. Some, such as Mounjaro, also act on a second hormone involved in appetite and blood sugar control.
Weight-loss drugs may also make it harder to absorb the contraceptive pill, due to common side-effects such as nausea and diarrhoea.
The MHRA also said the drugs - which are glucagon-like peptide-1 receptor agonists (GLP-1 or GLP-1 RAs) - must not be taken during pregnancy, while trying to get pregnant or during breastfeeding.
Anyone who gets pregnant while using the drugs should also stop taking the medicine, it added, because “there is not enough safety data to know whether taking the medicine could cause harm to the baby”.
In some cases, women are also advised to continue using contraception for up to two months between stopping the medicine and trying to get pregnant. The MHRA also stressed that weight-loss jabs should not be bought from unregulated sellers such as beauty salons or via social media, or taken without speaking to a health professional.
More than a million Britons are now on the jabs, with Mounjaro the most popular. The vast majority buy them privately from online pharmacies for about 200 pounds ($420) a month.
Dr Alison Cave, the MHRA’s chief safety officer, said: “Skinny jabs are medicines licensed to treat specific medical conditions and should not be used as aesthetic or cosmetic treatments. They are not a quick fix to lose weight and have not been assessed to be safe when used in this way.
“Our guidance offers patients a ‘one-stop shop’ for our up-to-date advice on how to use these powerful medicines safely. This guidance should not be used as a substitute to reading the patient information leaflet or having a conversation with a healthcare professional as part of the prescribing process.”
The latest guidance also reminds patients taking jabs of the symptoms to look out for in the event of acute pancreatitis, which, although uncommon, can be serious. The main symptom is severe pain in the stomach that radiates to the back and does not go away, and people should seek immediate medical help.
Dr Channa Jayasena, of Imperial College London, said: “The guidance produced by the MHRA is sensible, since it highlights that women could accidentally get pregnant when taking GLP-1 drugs.
“We don’t know how harmful GLP-1 drugs are during pregnancy; however, we know that other forms of weight loss like weight-loss surgery can increase chances of a miscarriage. So, women are advised to do all they can to prevent pregnancy while taking GLP-1 drugs.”
The Times
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