EXECUTIVE SUMMARY
Epilepsy affects 2.2 million Americans, of which approximately half are women of reproductive age. The Association of Reproductive Health Professionals has just released a webinar to help providers review evidence-based information on the subject.
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Hormonal contraception is safe and effective for many women with epilepsy. However, it is important to identify interactions between anti-epilepsy drugs (AEDs) and hormonal contraception. Variable interactions exist between hormonal contraceptives and anti-epileptic drugs. An AED may impact efficacy of hormonal contraception, and/or hormones can impact AED levels.
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Discuss That Intrauterine Contraception Can Be Used Safely By Women Who Are Nulliparous.
Epilepsy is common, affecting 2.2 million Americans, of which approximately half are women of reproductive age.1 The Association of Reproductive Health Professionals (ARHP) has just released a webinar, “Women with Nerve: Providing Reproductive Health Care for Women with Epilepsy,” to help providers review evidence-based information on the subject.
The webinar offers information on the interaction between epilepsy and women’s reproductive health, including tips on evaluating and recommending contraceptive options for women with epilepsy, the importance of planning pregnancy for these patients, and available resources to assist in their reproductive health care. (Go to http://bit.ly/1YuPX3f to view the webinar.) The webinar was co-presented by Caryn Dutton, MD, an instructor in obstetrics and gynecology at Harvard Medical School and the medical director of the gynecology clinic at Brigham and Women’s Hospital, both in Boston, and Amanda Dennis, DrPH, MBE, an associate in the Cambridge, MA, office of Ibis Reproductive Health, an international nonprofit organization with a mission to improve women’s reproductive autonomy, choices, and health worldwide.
Identify interactions between anti-epilepsy drugs (AEDs) and hormonal contraception, says Dutton. Variable interactions exist between hormonal contraceptives and anti-epileptic drugs. An AED may impact efficacy of hormonal contraception, and/or hormones can impact AED levels. There is very little high-quality research published on the interaction between AEDs and hormonal contraception, particularly for more modern AEDs and modern methods of birth control, states Dutton.
Use of combined oral contraceptives does not appear to change the incidence of epilepsy; however, endogenous hormones may increase or decrease seizure threshold, Dutton says. “Menstrual suppression is a reasonable approach for any woman with epilepsy, even if her seizure pattern is not clearly linked to the same time point in her cycle,” she states.
AEDs and steroid hormones are substrates of the Cytochrome P450 system in the liver; certain AEDs will induce metabolism and increase clearance of hormones, Dutton notes. Enzyme-inducing AEDs, therefore, can reduce levels of hormonal contraception and place women at higher risk of method failure. In addition, a unique interaction between lamotrigine and hormonal contraceptives containing estrogen will increase lamotrigine metabolism.2
The following AEDs are enzyme inducers:
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carbamazepine;
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felbamate;
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oxcarbazepine;
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phenobarbital;
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phenytoin;
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primidone;
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rufinamide.
The following AEDs are enzyme non-inducers:
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clobazam;
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clonazepam;
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ethosuximide;
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ezogabine;
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gabapentin;
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lacosamide;
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levetiracetam;
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pregabalin;
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tiagabine;
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vigabatrin;
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zonisamide.
Lamotrigine lowers the Cmax, area under the curve (AUC), and trough levels of the progestin levonorgestrel; however, lamotrigine does not impact levels of ethinyl estradiol.1 Another AED, topiramate, given at a dose of 200 mg a day, does not impact levels of norethindrone. Topiramate decreases AUC and Cmax, but not trough levels, of ethinyl estradiol when given at a dose of 200 mg a day.1
A good resource for contraceptive selection for women with epilepsy is the U.S. Medical Eligibility Criteria for Contraceptive Use (US MEC), says Dutton.3 The US MEC lists the criteria for use of contraceptive methods in specific medical conditions, based on best available evidence.
Regardless of any interactions, use of hormonal contraception is safe and effective for many women with epilepsy. Patients can use hormonal contraception with barrier methods to reduce risk of method failure, and even if there are anti-epilepsy drug interactions, any hormonal contraception is better than no method, says Dutton. In addition, intrauterine contraception can be used safely by women who are nulliparous. Finally, some women with epilepsy will associate seizures with their menstrual bleeding. These women can be reassured that unscheduled bleeding associated with use of some contraceptives — for example, the contraceptive shot — should not be a trigger for seizures.1
For women with epilepsy who are considering pregnancy, remember that some AEDs are teratogenic. The rate of fetal malformations with anti-epilepsy drug exposure is 2-11%.1 Women desiring pregnancy need expert advice on the decision to stay on their current AEDs or switch or change doses, states Dutton. Discourage women from stopping their AEDs without first consulting their neurologists.
USE PATIENT RESOURCES
To support women with epilepsy in navigating the challenges of reproductive health, Ibis Reproductive Health has created a contraceptive decisions aid, a tool designed to provide contraceptive information, says Dennis. The tool helps individuals clarify and communicate values related to their decision, and it also offers structured guidance for going through the steps of contraceptive decision-making. The decision aid is meant to be an adjunct to clinical advice. Clinicians can download it from Ibis’s website (http://bit.ly/1LhmFNA) to share with patients, she notes.
After conducting research about the specific sexual and reproductive health needs of female teens with epilepsy, Ibis also decided to create a website to meet their needs: http://girlswithnerve.com. The site’s format and content are driven by teens’ preferences, needs, and suggestions, including information about sexual and reproductive health issues and epilepsy, stories from other teens with epilepsy, structured guidance for talking with healthcare providers and parents, and blogs by teens with epilepsy.
REFERENCES
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Davis AR, Pack AM, Dennis A. Contraception for women with epilepsy. In: Allen RH, Cwiak C, eds. Contraception for the Medically Challenging Patient. New York: Springer; 2014.
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Dutton C, Foldvary-Schaefer N. Contraception in women with epilepsy: Pharmacokinetic interactions, contraceptive options, and management. Int Rev Neurobiol 2008; 83:113-134.
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Centers for Disease Control and Prevention. U.S. medical eligibility criteria for contraceptive use. MMWR 2010; 59(RR04):1-6.
