Contraception and epilepsy

Some methods of contraception may be less effective in preventing pregnancy for women taking certain anti-seizure medication (ASM). This is because some ASMs affect how well methods of contraception work.

ASMs are either enzyme-inducing or non-enzyme-inducing, although topiramate and perampanel can be either, depending on the dose.
 

Enzyme-inducing ASMs

Enzyme-inducing ASMs may affect methods of contraception that contain hormones, such as the Pill, or contraceptive implants, because they increase the amount of enzymes that break down hormones in the body. 

This means the hormones in contraceptives are broken down more quickly than usual, so they stay in the body for less time and are less effective in preventing pregnancy. 

If you take an enzyme-inducing ASM, you may be advised by your doctor to use a method of contraception that is not affected by your ASM, such as a barrier method, or to use more than one method to help prevent pregnancy.

Non-enzyme-inducing ASMs

Non-enzyme-inducing ASMs are unlikely to affect any form of contraception. However, see below for details on lamotrigine.

Perampanel and Topiramate are on both lists as it depends on the dose.
 

Lamotrigine - a special case

There is evidence that the Pill lowers lamotrigine levels in the blood, and this could lead to seizures happening. 

Research suggests that lamotrigine can lower the amount of progestogen from the combined oral contraceptive pill in the blood, but not the oestrogen. However, there is no conclusive evidence that lamotrigine reduces the effectiveness of the Pill.

If you take lamotrigine, it is important to talk to your doctor before starting any contraception that contains the hormones progestogen and oestrogen.
 

What is best for me?

You may want to talk to your neurologist, epilepsy specialist nurse (ESN), or a family planning advisor about the combination of ASM and contraception that is best for you.

Further information on contraception is available from Family Planning Association (FPA)  and the NHS website.

Further information

National Institute for Health and Care Excellence.
nice.org.uk/guidance/ng217 
Guidance on the diagnosis and treatment of epilepsy.

Epilepsy Society is grateful to Dr F J Rugg-Gunn, Consultant Neurologist & Honorary Associate Professor Clinical Lead, Chalfont Centre for Epilepsy, who reviewed this information.

Information updated: September 2023