Hormone replacement therapy in women with epilepsy: a randomized, double-blind, placebo-controlled study

Are lamotrigine kinetics altered in menopause? Observations from a drug monitoring database

To assess possible alterations in the pharmacokinetics of lamotrigine (LTG) in menopause, we reviewed the database of the drug monitoring service at the Karolinska University Hospital. Dose/plasma concentration (D/C) ratios of LTG in different age groups of women under treatment with LTG were compared with ratios for men. For further comparison, D/C ratios were calculated for men and women treated with carbamazepine (CBZ). D/C ratios were available for 752 men and 1115 women on LTG, and for 3464 men and 3088 women on CBZ. The D/C ratios of CBZ were very similar among men and women in all age groups under study. In contrast, LTG D/C ratios seemed to decline in women 51-55 years of age, and were in this age group significantly lower among women than among men (P<0.05). Our data suggest that there may be a transient decline in clearance of LTG in conjunction with presumed menopause.

Treatment of epilepsy in postmenopausal women

Menopausal women represent a rapidly growing proportion of the population. Epidemiologic evidence for the increased incidence of epilepsy in elderly patients suggests that with global aging of the population, there is likely to be a growing need for healthcare workers to manage seizures in older women. Unfortunately, there has been relatively little scientific investigation into the unique concerns of postmenopausal woman with epilepsy. There is some evidence that women may experience increased seizure activity during the menopausal transition owing to the effects of estrogen and progesterone on neuronal excitability. During perimenopause and menopause, use of hormone-replacement therapy can also worsen seizure control. Menopausal women are particularly vulnerable to osteoporosis and fragility fractures, both of which demonstrate increased risk following exposure to antiepileptic drugs. Optimization of epilepsy therapy to avoid both seizures and falls caused by antiepileptic drug-induced imbalance is crucial in order to minimize fracture risk in this group of women. Elderly patients are more susceptible to adverse medication side effects owing to drug interactions and the physiologic changes of aging that result in altered drug pharmacokinetics.

Hormonal aspects of epilepsy

The relationships among hormones, epilepsy, and the medications used to treat epilepsy are complex, with tridirectional interactions that affect both men and women in various ways. Abnormalities of baseline endocrine status occur more commonly in people with epilepsy. Abnormalities are most often described for the sex steroid hormone axis, commonly presenting as sexual dysfunction in men and women with epilepsy and lower fertility. Other signs and symptoms in women with epilepsy include menstrual irregularities, premature menopause, and polycystic ovarian syndrome. The evaluation and care of adult patients with epilepsy should include considerations of the common hormonal aberrations that occur in this patient population. Questions about reproductive health disorders, sexual function, symptoms of thyroid disorders, and bone health should be part of the evaluation of all adult patients with epilepsy. Further laboratory or radiologic testing and referral to other specialists to participate in collaborative care may be warranted if underlying disorders are suspected, especially given that many of these hormone abnormalities can result in long-term health risks as well as negatively affect quality of life. AEDs and hormones have a bidirectional interaction that can impair the efficacy of contraceptive hormone treatments and of the AEDs. Endogenous hormones can influence seizure severity and frequency, resulting in catamenial patterns of epilepsy. However, this susceptibility to hormonal influences can be used to develop hormonal strategies to improve seizure control in women with epilepsy with use of cyclic PROG supplementation or alteration of the endogenous hormone release. Additionally, development of the neurosteroid analog ganaxolone provides a novel approach that can potentially be used across both genders and all age groups.

The role of neurosteroids in the pathophysiology and treatment of catamenial epilepsy

Catamenial epilepsy is a multifaceted neuroendocrine condition in which seizures are clustered around specific points in the menstrual cycle, most often around perimenstrual or periovulatory period. Generally, a twofold or greater increase in seizure frequency during a particular phase of the menstrual cycle could be considered as catamenial epilepsy. Based on this criteria, recent clinical studies indicate that catamenial epilepsy affects 31-60% of the women with epilepsy. Three types of catamenial seizures (perimenstrual, periovulatory and inadequate luteal) have been identified. However, there is no specific drug available today for catamenial epilepsy, which has not been successfully treated with conventional antiepileptic drugs. Elucidation of the pathophysiology of catamenial epilepsy is a prerequisite to develop specific targeted approaches for treatment or prevention of the disorder. Cyclical changes in the circulating levels of estrogens and progesterone play a central role in the development of catamenial epilepsy. There is emerging evidence that endogenous neurosteroids with anticonvulsant or proconvulsant effects could play a critical role in catamenial epilepsy. It is thought that perimenstrual catamenial epilepsy is associated with the withdrawal of anticonvulsant neurosteroids. Progesterone and other hormonal agents have been shown in limited trials to be moderately effective in catamenial epilepsy, but may cause endocrine side effects. Synthetic neurosteroids, which enhance the tonic GABA-A receptor function, might provide an effective approach for the catamenial epilepsy therapy without producing hormonal side effects.

Gender-specific psychosocial impact of living with epilepsy

Although many psychosocial issues affect all people living with epilepsy, certain issues either are specific to one gender or have a different prevalence or significance between men and women with epilepsy. Most studies suggest that the incidence of epilepsy is slightly higher in males with epilepsy. Sexual dysfunction is common among men and women with epilepsy and has been related to epilepsy type and treatment. Women living with epilepsy are often prone to increased seizure frequency at certain phases of their menstrual cycles. Hormone replacement therapy in postmenopausal women may worsen seizures. Treatment during pregnancy is often a precarious balancing act between the teratogenic risks of AEDs and the maintenance of maternal seizure control. However, pregnancy registries and other prospective studies have given us invaluable information on how to optimize treatment regimens as well as information about safety of breastfeeding. These gender-specific factors should be a key consideration when counseling and treating patients with epilepsy.

Hormonal therapies: progesterone

Seizures do not occur randomly in the majority of people with epilepsy. They tend to cluster. Seizure clusters, in turn, commonly occur with a temporal rhythmicity that shows a readily identifiable and predictable periodicity. When the periodicity of seizure exacerbation in women conforms to that of the menstrual cycle, it is commonly known as catamenial epilepsy. This may be attributable to 1) the neuroactive properties of steroid hormones and 2) the cyclic variation in their serum levels. If hormones play a role in seizure occurrence, hormones may also have a role in treatment. Progesterone has potent GABAergic metabolites that may provide safe and effective seizure control in women who have catamenial epilepsy.

Epilepsy in older women

Women suffering from epilepsy require special attention throughout their life. In this review, management of epilepsy during the periods of perimenopause, menopause and late maturity is discussed. The effect of epilepsy on age at menopause, changes in seizure frequency during perimenopause and menopause, and the risks of hormone replacement therapy are also presented. Altered antiepileptic drug pharmacokinetics with increasing age and the management of this vulnerable population is also discussed.

Hormones, seizures, and lamotrigine: Oh, my!

Oral Contraceptives Induce Lamotrigine Metabolism: Evidence from a Double-Blind, Placebo-Controlled Trial. Christensen J, Petrenaite V, Atterman J, Sidenius P, Öhman I, Tomson T, Sabers A. Epilepsia 2007;48(3):484–489.

Purpose

This study evaluates the effect of oral contraceptives on lamotrigine (LTG) plasma concentrations and urine excretion of LTG metabolites in a double-blind, placebo-controlled, crossover study in patients with epilepsy.

Methods

Women with epilepsy, treated with LTG in monotherapy and taking combination-type oral contraceptives, were randomized to treatment with placebo or a standard combination-type contraceptive pill. The dose-corrected trough plasma concentration of LTG and the ratio of N-2-glucuronide/unchanged LTG on urine after 21 days of concomitant placebo treatment was analyzed versus those after 21 days of concomitant treatment with the oral contraceptive pill.

Results

The mean dose-corrected LTG concentration after placebo treatment was 84% [95% confidence interval (CI), 45–134%] higher than after oral contraceptives, signifying an almost doubling of the concentration after cessation of oral contraceptives. Most of this increase took place within the first week after oral contraceptives were stopped. The N-2-glucuronide/LTG ratio in the urine was decreased by 31% (95% CI, −20–61%) when shifting from oral contraceptives to placebo.

Conclusions

Cessation of oral contraceptives leads to an 84% increase in the concentration of LTG. In parallel, the excretion of the N-2-glucuronide was decreased, indicating that the changes are caused by altered LTG glucuronidation. The change in LTG concentrations was observed within 1 week of the shift of treatment, suggesting that induction and deinduction of LTG glucuronidation is faster than that seen for other metabolic pathways (e.g., cytochrome P450).

Hormone replacement therapy: will it affect seizure control and AED levels?

Interest in the years of reproductive changes for women with epilepsy (WWE), specifically perimenopause, menopause and postmenopause has been emerging in the epilepsy community. This article discusses evidence for changes in seizure frequency during perimenopause and postmenopause. Further, a catamenial epilepsy pattern during the reproductive years may be a hallmark for the observed seizure frequency change during these years; that is, an increase at perimenopause but a decrease at menopause. This finding implies that a subset of WWE are particularly susceptible to endogenous reproductive hormonal changes. An adverse effect on seizure frequency with the use of hormone replacement therapy (HRT) during postmenopause for WWE was reported in questionnaires, and was later borne out in a clinical trial. The laboratory counterpart of this human trial, HRT in ovariectomized rodent seizure models, shows that estrogen and progesterone are neuroprotective and do not uniformly increase seizure frequency. Possible reasons for the discrepancy between "the lab and the clinic" are presented. Strategies for managing HRT in symptomatic postmenopausal WWE using estrogenic and progestogenic compounds that may be less likely to promote seizures are discussed.

Alzheimer's disease and other neurological disorders

Menopausal status and estrogen-containing hormone therapy may influence several neurological disorders, including Alzheimer's disease, epilepsy, migraine headache, multiple sclerosis, Parkinson's disease, sleep disorders, and stroke. For most of these illnesses, evidence on hormone therapy is insufficient to guide practice decisions. For stroke, clinical trial evidence indicates that hormone therapy increases risk of cerebral infarction. For women with Alzheimer's disease, estrogen treatment trials have tended to be small and of short duration. Most suggest that estrogen started after the onset of dementia symptoms does not meaningfully improve cognition or slow disease progression. Hormone therapy initiated after age 64 increased all-cause dementia in the Women's Health Initiative Memory Study. Many observational studies, however, report protective associations between hormone use and Alzheimer risk. Apparent risk reduction may represent a bias toward hormone therapy, since hormones are more often prescribed to healthier women. However, when compared to the Women's Health Initiative Memory Study, estrogen exposures in many observational studies reflect hormone initiation at a younger age, closer to the time of menopause. One intriguing hypothesis is that hormone therapy initiated or used during an early critical window may reduce later Alzheimer incidence. Public health implications of this hypothesis are important, but current data are inadequate to decide the issue.

Pharmacology of antiepileptic drugs during pregnancy and lactation

Most women with epilepsy require continuous treatment during pregnancy, making antiepileptic drugs (AEDs) one of the most frequent chronic teratogen exposures. Therapeutic decisions should balance the risks to the developing fetus of AED exposure and of not treating or undertreating the epilepsy. The International AED Pharmacology Work Group of the Health Outcomes in Pregnancy and Epilepsy (HOPE) Forum identified four pharmacology topics critical to enhancing maternal and fetal outcomes for pregnancies exposed to AEDs: (1) hormonal therapies and endogenous changes: bidirectional interactions with AEDs; (2) pharmacokinetic alterations during pregnancy, the role of therapeutic drug monitoring, and the influence on seizure control and maternal and fetal outcomes; (3) multidrug transporters and their various roles during pregnancy; (4) breastfeeding in mothers taking AEDs. The report provides an overview of these key topics, highlights gaps in the current knowledge, and provides future directions for needed research.

Women with epilepsy: hormonal issues from menarche through menopause

Epilepsy is a multilayered disorder complicated by numerous comorbid conditions and hormonal changes. More than 1.5 million girls and women with epilepsy face side effects that are compounded at different ages by menstruation, fertility, pregnancy, fetal health, bone health, and other health issues. Changes in hormonal balance during maturation, from menarche through menopause, affect seizure thresholds and antiepileptic drugs, and vice versa. This overview provides physicians with a background on the multiple issues relevant to women of all ages in the reproductive years, including those planning to conceive and those who are pregnant, and beyond the childbearing years.

The current state of postmenopausal hormone therapy: update for neurologists and epileptologists

Appropriate and safe use of hormone replacement therapy (HRT) in postmenopausal women is an evolving saga, triggered by the unexpected results from the first publication of the Women's Health Initiative (WHI) Trial in 2002. These results showed a slight but significantly increased risk of breast cancer, stroke, and dementia with standard HRT compared with placebo. A reanalysis of these results shows that use of HRT within the first few years after the onset of menopause may be associated with decreased risk of dementia and coronary artery disease. However, HRT in its commonly used form of conjugated equine estrogen and medroxyprogesterone acetate can increase seizure frequency in menopausal women with epilepsy; this outcome may be an adverse effect of these neuroactive steroids on the epileptic female brain, which is already in a hormonally deprived state. To explore this possibility, more information about the neurophysiologic activity of medroxyprogesterone acetate is needed and alternatives to this specific HRT regimen should be considered for women with epilepsy.

Epilepsy

PURPOSE OF REVIEW

To provide a critical review of studies published between December 2005 and November 2006, and detect the advances of basic and clinical research in epilepsy.

RECENT FINDINGS

The complexity of the mechanisms underlying epileptogenesis and drug resistance was repeatedly highlighted. Seizure diagnosis and classification are still difficult, despite the use of valid and reliable instruments. Even well defined epilepsy syndromes may exhibit complex genetic patterns and atypical electroencephalogram features. Low prevalence rates of active epilepsy have been reported from several countries, suggesting underreporting for sociocultural reasons. Several pregnancy and neonatal factors can be found to increase the risk of epilepsy when accurate data are available from well defined populations. Early remission of seizures does not always predict terminal remission after prolonged follow-up. Cognitive regression may be associated with the presence of interictal electroencephalographic epileptiform abnormalities. A Cochrane review showed lamotrigine to be less frequently withdrawn than carbamazepine. However, these findings are contrasted by clinical practice, which showed no individual drug to be more likely to confer seizure freedom than any other.

SUMMARY

Recent research highlights the complexity of the mechanisms of epileptogenesis and drug response, and the difficulties with the classification of epilepsy into separate phenotypic categories.