From fat jabs to antibiotics – all the common medicines that can stop the pill working and get you pregnant
ACCIDENTLY falling pregnant isn’t something most of us expect when we take antibiotics or antifungals for athlete’s foot.
But some medicines could stop the contraceptive pill from working properly, increasing the risk of an unplanned pregnancy.
3
Now, experts warn that even weight loss jabs like Wegovy and Ozempic could interfere with how well the pill works.
Today, drug regulators cautioned that these popular treatments might reduce the pill’s effectiveness, especially in women who are overweight or obese.
This happens because common side effects of the jabs, like vomiting and diarrhoea, can stop the pill from being properly absorbed.
The medicines also slow down how quickly the stomach empties, which can affect absorption.
The Medicines and Healthcare products Regulatory Agency (MHRA), which issued the warning, says women should continue using contraception while taking GLP-1 medicines.
They also advise waiting before trying for a baby, two months after stopping Wegovy or Ozempic, and one month after stopping Mounjaro, also called the King-Kong jab for how effective it is.
For women on the blockbuster jab who take the pill, it’s recommended to use condoms for the first four weeks, or switch to a more reliable method like the coil or implant.
So, what other drugs could have the same effect?
Most antibiotics don’t affect the pill, but rifampin, used to treat tuberculosis, is a known exception.
It speeds up how your body breaks down contraceptive hormones, making the pill less effective.
The Centers for Disease Control and Prevention (CDC) advises using backup contraception while taking rifampin and for 28 days afterward.
Some anti-seizure drugs like carbamazepine and phenytoin also interfere with the pill.
Like rifampin, they speed up hormone metabolism, meaning the pill may not work as well.
The Epilepsy Foundation warns that these medications can reduce the reliability of hormonal contraception.
3
Some antifungal drugs, such as griseofulvin and ketoconazole, are suspected to interfere with the pill.
Griseofulvin is used to treat skin infections like athlete’s foot and jock itch.
Ketoconazole is generally used when other antifungals haven’t worked.
The Faculty of Sexual & Reproductive Healthcare (FSRH) says there’s not much solid proof that these drugs reduce the pill’s effectiveness in real life.
However, the British National Formulary (BNF), which provides medics with drug advice, recommends using extra contraception during treatment and for one month afterwards, just to be safe.
Certain HIV drugs drugs can affect the pill too.
The Faculty of Sexual & Reproductive Healthcare (FSRH) says some of these “may reduce the effectiveness of hormonal contraceptives.”
This includes treatments like darunavir (Prezista), efavirenz (Sustiva), lopinavir/ritonavir (Kaletra), and nevirapine (Viramune).
They advise using condoms or switching to a non-hormonal method if you’re on one of these medications.
DR Zoe Williams is The Sun’s resident GP.
Q: What if I am pregnant and taking fat jabs?
The fact these drugs suppress appetite means the majority of women who got pregnant on them will have come off, because they are nourishing their baby.
The advice is to come off them immediately if you’re either pregnant or breastfeeding and speak to your doctor if you have any concerns.
Q: Why has this advice been issued now?
It is because not enough is known about the effect on pregnancy.
It’s not from studies that found any adverse effects.
As a result, the advice is preventative until more is known.
If women are on any weight loss jabs and want a baby, the advice is to come off it at least two months before trying.
Q: Are fat jabs going to be the ‘new thalidomide’ scandal?
No, the GLP-1 drugs are peptides that work by mimicking existing proteins in our bodies. In contrast, thalidomide is a drug that can affect blood vessel growth.
It is not likely that the jabs would cause such significant birth defects, as seen with thalidomide.
So far there has been no evidence of danger to the baby, despite many women getting pregnant on them.
Q: I’m worried and don’t know what to do?
When news like this breaks, it is common to have patients get in touch with concerns.
Stop taking the medication.
But be reassured, there is nothing your GP or midwife will need to do urgently.
If they are really concerned, they will get in touch.
Modafinil, used to treat sleep disorders like narcolepsy and sleep apnea, can also mess with the pill.
It speeds up how your body processes hormones, which might make the pill less effective.
The British National Formulary (BNF) suggests playing it safe by using extra contraception, like condoms, while on modafinil and for two months after stopping.
St John’s Wort is a common herbal remedy for mild to moderate depression, but if you take it, be aware it can reduce the effectiveness of the pill.
Like many of the other drugs listed here, it increases how quickly contraceptive hormones are broken down in the body.
The MHRA warns that St John’s Wort can interfere with hormonal contraceptives, so it’s best to use a backup method like condoms while taking it.
3
thesun
