Epilepsy and contraception

What are liver enzyme inducers?

Liver enzyme inducers are certain anti-epilepsy medicines that speed up how quickly some contraceptive pills and injections are processed by the liver. This can make these contraceptives less effective.

Which specific anti-epilepsy medicines are considered liver enzyme inducers?

The anti-epilepsy medicines that are liver enzyme inducers include carbamazepine, eslicarbazepine, oxcarbazepine, phenobarbital, phenytoin, primidone, and topiramate.

What if my anti-epilepsy medicine is not a liver enzyme inducer? Are my contraceptive options still affected?

If you are taking an anti-epilepsy medicine that is not a liver enzyme inducer, such as sodium valproate or ethosuximide, your contraceptive choices, doses, and recommendations are usually the same as for any other woman. However, lamotrigine is an exception and may still interact with the combined oral contraceptive pill.

What types of contraception are generally recommended if I am taking a liver enzyme-inducing medicine for epilepsy?

If you are taking a liver enzyme-inducing medicine, barrier methods of contraception (like condoms), or any type of coil (including the intrauterine system), are usually the most suitable options.

If I'm using emergency contraception and taking a liver enzyme inducer, do I need to do anything differently?

Yes, if you use emergency contraception tablets, the initial dose of levonorgestrel needs to be increased to 3 mg. This means you will need to take two tablets instead of the usual one.

Can I use the Depo-Provera® injection if I am taking a liver enzyme-inducing medicine?

Yes, the progestogen injection called Depo-Provera® can be used, but the injections will need to be given more frequently than usual to maintain effectiveness.

Why is lamotrigine mentioned separately, even though it's not a liver enzyme inducer?

Lamotrigine may interact with the combined oral contraceptive (COC) pill in a different way. This interaction can make both the pill and lamotrigine less effective, potentially increasing your risk of seizures. Due to this, adjusting medication doses may be necessary, or an alternative contraceptive method might be preferred.