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PEER REVIEW: EPILEPSY Contraceptive Choice in Women on Antiepileptic Drugs (AEDs) Introduction
efficacy of contraceptives while Written by Authors: Sarah Cullen and Benedetta Soldati some contraceptives affect the It is crucial to counsel all women efficacy of AEDs (see table below). of childbearing age about As a consequence, the rate of oral future pregnancies, since half contraceptive failure is expected to Contraceptive on Antiepileptic Drugs (AEDs) of all pregnanciesChoice happen in to Women be be much higher in women taking unplanned. This recommendation enzyme-inducing AEDs compared becomesby even moreCullen important Written Sarah andfor Benedetta to theSoldati general population. For women with epilepsy, where all women on enzyme inducing AEDs, pregnancies should be planned the World Health Organisation and preconception advice should (WHO) recommends against the Introduction be sought. Considering that 25% use of the combined hormonal of people with epilepsy in Ireland contraception (pill, patch, ring) or areischild-bearing only contraception It crucial to women, counselthis all womenprogesterone of childbearing age about future pregnancies, since half of all amounts to about 10,000 people (implant, mini-pill). The copper pregnancies happen to be unplanned. This recommendation becomes even more important for women who we must consider the use of IUD, levonorgestrel IUD and the with epilepsy,for. where all pregnancies should be planned and preconception advice should be sought. contraceptives medroxyprogesterone acetateConsidering that 25% of people with epilepsy in Ireland are child-bearing women, this amounts to about depot injection (DMPA) are not What does contraception involve attenuated by contraceptives drug interactions, 10,000 people who we must consider the use of for. for a woman with epilepsy? and are therefore the suggested alternative for women on enzymeContraception can be divided into Sarah Cullen, (Pharmacy Intern, NMH) What does contraception involve for a woman inducing AEDs. with epilepsy? three main types: natural, barrier and hormonal methods. As natural Emergency contraception methods are notcan appropriate Contraception be divided into three main types – natural, hormonal and barrier methods. As natural choices while taking for women of child-bearing age Lamotrigine andnot Sodium methods are not appropriate for women of child-bearing they will be discussed enzyme-inducing AEDsage with epilepsy, with epilepsy, they will not be Valproate further. discussed further. Levonorgestrel and ulipristal Lamotrigine levels are decreased acetate are the two types Barrier methods include condoms, by coil. combined hormonal of emergency hormonal and the copper Barrier methods include condoms, femidoms, diaphragms The copper coil is a good femidoms, diaphragms and the contraception. For women who contraception (EHC). These are copper coil. for The women copper coil is alternative searching forboth a long-term contraceptive solution without the hormonal effects. are taking the COC alongside heavily impacted by enzymea good alternative for women lamotrigine, this may result in a inducing medications. The copper Condoms alone are not strongly recommended because of the risk of failure. searching for a long-term reduced efficacy of lamotrigine coil is a non-hormonal form of contraceptive solution without the during the pill cycle and an emergency contraception (EC) Hormonal methods include the following; combined contraceptive pillincrease (COC),in progesterone only pill hormonal effects. Condoms alone lamotrigine levels and, as such, it is not affected by are not strongly recommended (mini-pill), contraceptive implant, patch, depot injection, hormonal coilduring and the thevaginal pill free ring. break.Hormonal This enzyme-inducing medications. because of the risk of failure. means women women may more contraceptive methods are the mostAs commonly chosen byinwomen, withbe epilepsy. women may present need including likely to experience loss in seizure Hormonal methods include the of EC, it is strongly recommended control during the pill cycle and following: combined contraceptive that, if EC is necessary, they are Enzyme-inducing AEDs and contraception experience lamotrigine toxicity on pill (COC), progesterone only pill referred to their doctor to avail their pill-free interval. (mini-pill), contraceptive implant, of the copper coil, as this is the Enzyme-inducing AEDs can interact with hormonal contraceptives. Interaction types – some patch, depot injection, hormonal Sodium valproate hasvary caused safest and most effective form coil and the vaginal ring. Hormonal birth defects in babies whose of emergency contraception in AEDs may affect the efficacy of contraceptives while some contraceptives affect the efficacy of AEDs contraceptive methods are the mothers had taken the drug during those taking enzyme-inducing (see below). As abyconsequence, the rate of oral contraceptive failure is expected to be much higher mosttable commonly chosen women, pregnancy and, therefore, it is not medications. If it is not possible including women with epilepsy. in women taking enzyme-inducing for AEDs compared totouch the general population. For women on enzyme recommended for the treatment of a patient to get in with epilepsy in women child-bearing their doctor, or (WHO) if they dorecommends not Enzyme-inducing AEDs and Health Organisation inducing AEDs, the World against the use ofofthe combined age. It is only to be considered if wish to avail of the copper coil, contraception hormonal contraception (pill, patch,levonorgestrel ring) or progesterone only (implant, mini-pill). The there is no alternative and it must can be given at contraception Enzyme-inducing AEDs be used in conjunction with the double the usual dose (3mg). There Copper IUD, levonorgestrel IUD and the medroxyprogesterone acetate-depot injection (DMPA), are can interact with hormonal ‘Valproate Pregnancy Prevention is no evidence to recommend the not attenuated Interaction by drug interactions, andofare therefore thefor suggested for women on itenzymecontraceptives. types use ulipristal acetate patients alternative Programme’. As a result, is rarely vary: someAEDs. AEDs may affect the on enzyme-inducing medications. used in women with childbearing inducing
Submission Date: 24-06-2022
AEDs that decrease the serum levels of hormonal contraceptives Carbamazepine Oxcarbazepine Phenobarbital Phenytoin Topiramate (reduce ethinylestradiol only) Eslicarbamazepine Primidone Lamotrigine (reduces progesterone only)
Word Count: 907 + table
AEDs that do not affect the serum levels of hormonal contraceptives Levetiracetam Gabapentin Vigabatrin Pregabalin Zonisamide Sodium Valproate Tiagabine Lacosamide
AEDs whom levels have been reduced by hormonal contraceptives Lamotrigine Sodium Valproate
Benedetta Soldati, (Sr. Pharmacist, NMH)
potential. However, it is important to highlight that ethinylestradiol can modestly reduce its levels. Conclusion In conclusion, the prevalence of women with epilepsy who are of childbearing age means it is important for healthcare professional to be aware of the considerations of contraception. Furthermore, women taking AEDs may present looking for preconception advice. Healthcare professionals should advise women who wish to become pregnant while on AEDs to engage with their consultants to optimise their medications and begin a course of folic acid. It is recommended that women on AEDs begin taking 5mg of folic acid at least three months prior to conception and remain on this dose throughout the pregnancy. The HSE National Clinical Programme for epilepsy recommends that women with epilepsy who are considering becoming pregnant engage with preconception planning 12 months before conception. Though this article focused on women of child-bearing age, it is important to remember that hormonal replacement therapy (HRT) can also interact with AEDs. Common medications used in HRT such as estradiol and dydrogesterone have similar effects to COCs, and while there is no longer a concern of pregnancy, the efficacy of both the HRT and the AED must be considered. References available on request
HOSPITALPROFESSIONALNEWS.IE | HPN • AUGUST 2022
