• Medicines watchdog issued new guidance over emergency contraceptive
  • Pills which contain levonorgestrel linked to 400 pregnancies since 1970s
  • Warned women taking medicines for epilepsy, tuberculosis, HIV and fungal infections might need to take double the dose to be effective

Kate Pickles For Mailonline



Women using the morning after pill may need a double dose to avoid conceiving if they are taking other drugs.

Medicines for epilepsy and common infections – as well as some herbal remedies – can interfere with the emergency contraceptive and make it ineffective.

The morning after pill (known as Plan B in the US) contains the progesterone levonorgestrel.

It stops the ovaries releasing eggs and irritates the lining of the uterus, making it incredibly difficult for a fertilized egg to implant.

But when paired with common anti-seizure medication such as phenytoin, or herbal remedies to ease stress, the hormone to kick-start this process is drowned out. 

Medicines for epilepsy and some common infections – as well as herbal remedies such as St John’s Wort – can interfere with the emergency contraceptive and make it ineffective

It is a global concern that few women are aware of. 

And now, after at least 400 unwanted pregnancies, the British medicine watchdog Medicines and Healthcare Products Regulation Agency (MHRA) is releasing new guidelines. 

The guidelines, released on Thursday, urge women to take two packs of emergency contraceptive, instead of the standard one, if they are on medication. 

A spokesman said it was not clear how many of these pregnancies since 1970 were due to interactions with other drugs. 

But he said research has shown a link.

The MHRA said that women taking medicines for epilepsy, tuberculosis, HIV and fungal infections may need to take a double dose of the emergency contraceptive for it to be effective.

Women taking herbal remedies containing St John’s Wort are also affected.

Dr Sarah Branch, deputy director of MHRA’s vigilance and risk management of medicines division, said: ‘This is important new advice for women who want to use the emergency contraceptive pill.

‘It will help to protect women who are taking certain medicines against unwanted pregnancies.

It said it had data on 400 unwanted pregnancies in women taking levonorgestrel since it was first licensed in the 1970s and women taking certain medications would need a double dose

‘Our new patient information sheet provides information on what types of medicines could interfere with how the emergency contraceptive works.

‘It tells women what steps they need to take to ensure they receive the correct dose.

‘The earlier that emergency contraception is taken after unprotected intercourse, the better it works.’

The new information sheet will be available through GP surgeries and pharmacies.

Levonorgestrel has to be taken within 72 hours (three days) of unprotected sex.


Most watched News videos

  • Syrian rebel takes selfie with phone rigged to bomb

  • Gang of neo-Nazis in vicious street fight with migrants in Germany

  • Epic moment Trump allows Jimmy Fallon to mess up his hair

  • Prisoner appears to headbutt guard moments before execution

  • Clashes in Germany between far-right protesters and refugees

  • Prince William rushes to the aid of veteran who takes tumble

  • Moment woman uses hijab to shoplift and gets caught in the act

  • Mob of students angry over cultural appropriation email

  • Video shows road rage between school bus and FedEx truck in NJ

  • Woman’s shock as police shoot dog dead while attending home

  • Protester grabs microphone at Tim Kaine rally in New Hampshire

  • Model’s nipples send internet into frenzy during QVC clip

Comments (41)

Share what you think

The comments below have not been moderated.

The views expressed in the contents above are those of our users and do not necessarily reflect the views of MailOnline.

Find out now