Contraception and Epilepsy
Why the epilepsy medicine matters when choosing contraception
Having epilepsy does not mean someone cannot use contraception.
Most contraceptive methods can be used by people with epilepsy. The important question is whether the particular contraceptive and the particular antiseizure medicine interact with each other.
Some antiseizure medicines can make hormonal contraception less effective.
Some hormonal contraceptives can change the amount of an antiseizure medicine in the bloodstream.
This is especially important with medicines such as lamotrigine, enzyme-inducing antiseizure medicines, valproate and topiramate.
Contraception may also be used for reasons other than pregnancy prevention, including:
reducing heavy bleeding
making periods more predictable
menstrual suppression
managing painful periods
or other gynaecological conditions.
The best method therefore depends on the person's epilepsy treatment, health, preferences and reason for using contraception.
Why can epilepsy medicines affect contraception?
Some antiseizure medicines increase the activity of liver enzymes that break down hormones.
These are commonly called enzyme-inducing medicines.
If contraceptive hormones are broken down more quickly, their level in the body can fall and the contraceptive may become less reliable.
FSRH guidance states that enzyme-inducing drugs can reduce the effectiveness of:
combined hormonal contraception
progestogen-only pills
the etonogestrel contraceptive implant
and oral emergency contraception.
The contraceptive injection, hormonal intrauterine system and copper IUD are not thought to lose effectiveness because of this type of interaction.
Which epilepsy medicines can interfere with hormonal contraception?
NICE specifically highlights medicines including:
carbamazepine
oxcarbazepine
phenytoin
topiramate
as examples that can impair the effectiveness of hormonal contraception.
Other antiseizure medicines can also have clinically important interactions.
Epilepsy Action's current UK information includes medicines such as:
carbamazepine
cenobamate
eslicarbazepine
oxcarbazepine
perampanel
phenobarbital
phenytoin
primidone
rufinamide
and topiramate
among medicines that may affect hormonal contraception.
Not every interaction is identical, and some are dose-dependent.
For this reason, the exact medicine and dose should be checked rather than assuming all antiseizure medicines behave in the same way.
Which contraceptives can be affected?
When someone is taking an enzyme-inducing antiseizure medicine, effectiveness may be reduced for:
Combined contraceptive pill
The combined pill contains oestrogen and a progestogen.
Enzyme induction can make those hormones leave the body more quickly and may reduce protection against pregnancy.
Progestogen-only pill
The progestogen-only pill, often called the mini-pill, can also be affected by enzyme-inducing medicines.
Contraceptive implant
The etonogestrel implant may become less reliable when used with enzyme-inducing medicines.
Contraceptive patch
The patch is a form of combined hormonal contraception and can also be affected.
Vaginal ring
The vaginal ring is also combined hormonal contraception and may be affected by enzyme induction.
Oral emergency contraception
The emergency contraceptive pills can also be less reliable when someone is taking, or has recently taken, an enzyme-inducing drug.
Which methods are not affected by enzyme induction?
Professional UK guidance identifies several methods whose effectiveness is not expected to be reduced by enzyme-inducing medicines.
These include:
Copper IUD
The copper intrauterine device contains no hormones.
Its contraceptive effectiveness is not affected by antiseizure medicines.
Hormonal IUS
A levonorgestrel-releasing intrauterine system acts mainly within the uterus.
Its contraceptive effectiveness is not expected to be reduced by enzyme-inducing medicines.
Contraceptive injection
Depot medroxyprogesterone acetate, usually known as DMPA, reaches sufficiently high hormone levels that its effectiveness is not thought to be reduced by enzyme induction.
Barrier contraception
Condoms are not affected by antiseizure medicines.
They are also the contraceptive method that can reduce the risk of many sexually transmitted infections.
Lamotrigine is different
Lamotrigine deserves its own discussion because the interaction works differently.
Lamotrigine is not simply a straightforward example of the classic liver-enzyme interaction.
The major concern is that oestrogen-containing contraception can substantially lower lamotrigine levels.
NICE specifically warns that oestrogen-containing hormonal contraceptives can impair the effectiveness of lamotrigine.
That can matter because a lower lamotrigine concentration may mean poorer seizure control.
Which contraceptives can lower lamotrigine?
The interaction is particularly important with combined hormonal contraception, including:
the combined contraceptive pill
the contraceptive patch
the vaginal ring.
Oestrogen can increase the breakdown of lamotrigine, reducing the amount in the bloodstream.
For some people, this can increase the risk of breakthrough seizures.
What happens during the pill-free week?
The interaction can become even more complicated if the contraceptive includes a hormone-free interval.
While oestrogen-containing contraception is being taken, lamotrigine levels can fall.
During a pill-free or hormone-free interval, the amount of lamotrigine can then rise again.
FSRH guidance warns that this fluctuation may create a risk of:
inadequate seizure control while hormones are being taken
followed by higher lamotrigine exposure and possible side effects during the hormone-free interval.
Possible symptoms of excessive lamotrigine exposure can include:
dizziness
poor coordination
double vision
or other dose-related adverse effects.
Anyone taking lamotrigine should discuss starting, stopping or changing hormonal contraception with their epilepsy team rather than making the change without informing them.
Can progestogen-only contraception affect lamotrigine?
Possibly.
Evidence is much more limited than for oestrogen-containing contraception.
FSRH notes that desogestrel may increase lamotrigine exposure in some people, although evidence about other progestogen-only methods is limited.
This is another reason that symptoms and medication changes should be reviewed individually rather than assuming every progestogen method behaves in exactly the same way.
Can lamotrigine make contraception less effective?
There is some uncertainty here too.
Research suggests lamotrigine may modestly reduce exposure to contraceptive progestogens.
FSRH notes that the clinical effect on contraceptive reliability is not clearly established because the available evidence is limited.
For people using lamotrigine, contraceptive choice should therefore be discussed with someone able to consider both:
seizure control
and
pregnancy prevention.
Methods such as the copper IUD, hormonal IUS and DMPA injection are not expected to have their effectiveness reduced by lamotrigine.
Topiramate needs particular care
Topiramate can be used to treat epilepsy and is also used for migraine prevention.
It is particularly important when discussing contraception because:
it may reduce the effectiveness of some hormonal contraception; and
exposure during pregnancy can cause serious harm to an unborn child.
NICE lists topiramate among antiseizure medicines that can impair hormonal contraceptive effectiveness.
FSRH advises treating topiramate cautiously as a potential enzyme inducer because enzyme induction is clearer at higher doses but individual variation exists.
The UK Topiramate Pregnancy Prevention Programme
Current MHRA rules state that topiramate should not generally be used by women or girls who could become pregnant unless the requirements of the Pregnancy Prevention Programme are met.
This includes:
pregnancy testing before treatment
understanding the pregnancy risks
using highly effective contraception
completing a Risk Awareness Form
and treatment review at least annually.
Contraception should be used throughout topiramate treatment and for at least four weeks after the final dose.
For epilepsy, topiramate should not be stopped suddenly if pregnancy is suspected.
Urgent advice should instead be obtained from the epilepsy team because abrupt withdrawal can cause seizures to return or worsen.
Valproate and contraception
Valproate has particularly important reproductive safety requirements.
Exposure to valproate during pregnancy is associated with a high risk of congenital abnormalities and neurodevelopmental problems.
Current MHRA guidance says valproate should not be prescribed to a woman or girl who could become pregnant unless the conditions of the Valproate Pregnancy Prevention Programme are followed.
The programme requires the reproductive risks to be discussed and, where applicable, highly effective contraception to be used.
Valproate should never be stopped suddenly without specialist advice.
Which contraception is considered highly effective?
For pregnancy-prevention programmes, methods with very low typical-use failure rates are preferred.
Examples include:
copper IUD
hormonal IUS
contraceptive implant where there is no interacting enzyme-inducing drug
and sterilisation.
The exact suitable method depends on what other medicines the person is taking.
For example, an implant may be considered highly effective in general, but it can become less reliable if an enzyme-inducing medicine is also being used.
So “highly effective” does not automatically mean “suitable with every epilepsy medicine.”
Emergency contraception and epilepsy medicine
Emergency contraception becomes especially important if:
contraception has failed
pills have been missed
a condom has broken
an interacting medicine has been started
or unprotected sex has occurred.
Anyone seeking emergency contraception should tell the pharmacist, GP, sexual-health clinician or contraception service exactly which epilepsy medicines they take.
Copper IUD as emergency contraception
The copper IUD is the most effective form of emergency contraception and its effectiveness is not reduced by enzyme-inducing medicines.
FSRH recommends offering a copper IUD where appropriate to someone who requires emergency contraception while using an enzyme-inducing drug.
It can also continue to provide ongoing contraception afterwards if the person wishes.
Emergency contraceptive pills and enzyme-inducing medicines
Enzyme-inducing drugs can reduce the effectiveness of oral emergency contraception.
FSRH advises that if a copper IUD is unsuitable or not accepted, a 3 mg dose of levonorgestrel — twice the usual standard dose — may be considered.
However, people should be told that the effectiveness of this adjusted dose is uncertain.
Ulipristal acetate may also be affected by enzyme induction, and simply doubling the ulipristal dose is not recommended.
Because the advice depends on the medicine, timing and contraceptive method already being used, emergency contraception is a situation where same-day professional advice is particularly important.
What if someone has only just stopped an enzyme-inducing medicine?
The interaction does not necessarily disappear as soon as the last tablet is taken.
FSRH guidance advises that reduced contraceptive effectiveness may persist for a period after an enzyme inducer has been stopped.
For many contraceptive decisions, precautions may be required for 28 days after stopping the enzyme-inducing medicine.
The exact advice should be checked for the specific medicine.
What if more than one epilepsy medicine is taken?
Polytherapy means taking more than one antiseizure medicine.
If even one of those medicines has an important contraceptive interaction, the contraceptive plan needs to take that interaction into account.
Do not assume another non-interacting medicine cancels out the effect.
A pharmacist, epilepsy specialist or sexual-health clinician can check the complete medication list.
Are there epilepsy medicines that do not reduce contraceptive effectiveness?
Yes.
Many modern antiseizure medicines are not known to reduce the effectiveness of contraception through enzyme induction.
Current Epilepsy Action information lists examples including:
brivaracetam
clobazam
clonazepam
ethosuximide
gabapentin
lacosamide
levetiracetam
stiripentol
tiagabine
vigabatrin
and zonisamide.
However, this does not mean every medicine is completely free of reproductive considerations.
Pregnancy safety and contraceptive interaction are two different questions.
Pregnancy safety is not the same as contraceptive interaction
A medicine can have pregnancy-related risks even if it does not make contraception less effective.
Likewise, another medicine may interact with contraception but have a different pregnancy-risk profile.
This distinction matters.
The questions are:
Will this medicine make my contraception less reliable?
and separately:
What are the risks if pregnancy occurs while I am taking this medicine?
Both need to be considered.
Contraception and seizure patterns
Some people use hormonal contraception partly to change or suppress menstruation.
For someone with a suspected menstrual-related seizure pattern, altering hormone cycles or bleeding patterns may also change the pattern they are tracking.
That does not mean hormonal contraception will necessarily improve or worsen seizures.
The effects differ between individuals.
If seizures change after starting, stopping or changing contraception, record:
when the contraceptive changed
what method was used
seizure dates
bleeding pattern
medication doses
and any other possible triggers.
Take that information to the epilepsy team.
Related Information Hub pages:
Menstruation and Epilepsy
Catamenial Epilepsy
Do condoms still matter?
Yes.
Even when another highly effective method is being used, condoms may still be useful.
They are the only contraceptive method discussed here that also provides protection against many sexually transmitted infections.
With some interacting medicines, professional guidance may also recommend a barrier method in addition to another contraceptive.
What about men taking valproate?
Current UK advice also includes precautions for males taking valproate.
MHRA guidance recommends that, as a precaution, men taking valproate and their female partners use effective contraception during treatment and for three months after valproate is stopped.
This allows time for one sperm cycle after exposure to valproate.
Men who are planning a family should discuss treatment options with their specialist rather than stopping valproate themselves.
Starting or stopping contraception
Starting contraception is not the only time interactions matter.
Tell the epilepsy team if you are:
starting hormonal contraception
stopping hormonal contraception
changing from one method to another
having an implant or IUD inserted or removed
changing from cyclic to continuous hormonal contraception
or using emergency contraception.
This is especially important with lamotrigine, because changes in oestrogen exposure can alter lamotrigine concentrations.
Never stop epilepsy medicine because of contraceptive concerns
If someone discovers that their epilepsy medicine and contraception interact, the answer is not to suddenly stop the epilepsy medicine.
Abrupt withdrawal of an antiseizure medicine can lead to:
breakthrough seizures
seizure clusters
prolonged seizures
or serious deterioration in seizure control.
Instead, speak to:
the epilepsy specialist
epilepsy specialist nurse
GP
pharmacist
or sexual and reproductive health service.
Often the contraceptive method can be changed without destabilising epilepsy treatment.
What should someone ask at an appointment?
Useful questions include:
Does my epilepsy medicine affect this contraceptive?
Could this contraceptive change my epilepsy-medicine level?
Do I need a contraceptive that is unaffected by enzyme induction?
Does lamotrigine need monitoring if I start or stop this method?
Does my medicine have pregnancy-related risks?
Do I need a Pregnancy Prevention Programme?
What should I do if I need emergency contraception?
How long do interactions continue after stopping my medicine?
What should I do if I want to become pregnant in the future?
Taking a current medication list to the appointment can help.
The most important message
People with epilepsy have many contraceptive choices.
The challenge is not epilepsy itself.
It is making sure the contraceptive and the antiseizure medicine are compatible.
Some antiseizure medicines increase the breakdown of contraceptive hormones and can make pills, patches, rings and implants less reliable.
Oestrogen-containing contraception can substantially reduce lamotrigine levels and may affect seizure control.
Valproate and topiramate have additional UK pregnancy-prevention requirements because of their reproductive risks.
The safest approach is to check the exact medicine, exact dose and exact contraceptive method rather than relying on general rules.
And if contraception or epilepsy treatment needs changing, make the change with appropriate medical advice rather than stopping antiseizure medication suddenly.
Sources and further reading
NICE — Epilepsies in children, young people and adults (NG217).
Current UK guidance recommends regular discussion of contraception and reproductive health, recognises interactions between some antiseizure medicines and hormonal contraception, and specifically warns about oestrogen-containing contraception reducing lamotrigine effectiveness. Last updated January 2025.
Faculty of Sexual & Reproductive Healthcare — Drug Interactions with Hormonal Contraception.
Professional UK guidance on enzyme-inducing drugs, contraceptive effectiveness, lamotrigine and topiramate interactions.
Faculty of Sexual & Reproductive Healthcare — Emergency Contraception guideline.
Guidance covering copper IUDs, levonorgestrel and ulipristal when enzyme-inducing medicines are being used.
Epilepsy Action — Contraception and epilepsy.
Current UK patient information covering contraception, enzyme-inducing antiseizure medicines, lamotrigine, topiramate and valproate.
MHRA — Topiramate: Pregnancy Prevention Programme.
UK regulatory requirements concerning contraception, pregnancy testing, annual review and pregnancy risks associated with topiramate.
MHRA — Valproate: reproductive risks.
Current UK safety requirements covering valproate prescribing and pregnancy prevention.
Information reviewed: September 2026.
This page provides general educational information. Contraceptive and antiseizure-medicine interactions can be complex and should be checked for the individual medicine, dose and contraceptive method. Do not stop antiseizure medication without specialist medical advice.
