Hormone binding globulins and anticonvulsant therapy

Special Considerations in the Management of Women with Epilepsy in Reproductive Years

Anti-seizure medications (ASMs) fail to prevent seizure recurrence in more than 30% of patients with epilepsy. The treatment is more difficult in premenopausal women with epilepsy (WWE) because changes in plasma estrogen and progesterone concentrations during the menstrual cycle often affect seizure frequency and intensity. Interactions between enzyme-inducin ASMs and hormonal contraceptives can lead to both a loss of seizure control and failure of contraception. Significant changes in the function of the liver and kidneys during pregnancy can accelerate metabolism and elimination of ASMs, causing breakthrough seizures. In addition, the teratogenic, cognitive, and psychological effects of ASMs on potential offspring have to be considered when choosing the best ASM regimen. Therefore, aspecialized approach is necessary for the treatment of premenopausal WWE.

Cortisol levels and seizures in adults with epilepsy: A systematic review

Stress has been suggested as a trigger factor for seizures in epilepsy patients, but little is known about cortisol levels, as indicators of stress, in adults with epilepsy. This systematic review summarizes the evidence on this topic. Following PRISMA guidelines, 38 articles were selected: 14 analyzing basal cortisol levels, eight examining antiepileptic drugs (AEDs) effects, 13 focused on seizure effects, and three examining stress. Higher basal cortisol levels were found in patients than in healthy people in studies with the most homogeneous samples (45% of 38 total studies). Despite heterogeneous results associated with AEDs, seizures were related to increases in cortisol levels in 77% of 38 total studies. The only study with acute stress administration found higher cortisol reactivity in epilepsy than in healthy controls. In studies using self-reported stress, high seizure frequency was related to increased cortisol levels and lower functional brain connectivity. Findings suggest that epilepsy could be considered a chronic stress model. The potential sensitizing role of accumulative seizures and issues for future research are discussed.

Psychotropics and Male Reproduction

Psychotropic drugs, including antidepressants, antipsychotics, and anticonvulsants, all have negative effects on sexual function and semen quality. These adverse events vary among men and are less pronounced for some medications, allowing their effects to be managed to some extent. Use of specific serotonin reuptake inhibitors (SSRIs) is prevalent in men of reproductive age; and application to treat premature ejaculation increases the number of young men on SSRI therapy. Oxidative damage to sperm can result from prolonged residence in the male reproductive tract. The increase in ejaculatory latency seen with SSRIs likely underlies some of their negative effects on semen quality, including higher sperm DNA fragmentation, seen in all SSRIs evaluated thus far. These medications increase prolactin (PRL) levels in some men, and this is often credited with inhibitory effects on male reproduction; however, testosterone levels are generally normal, reducing the likelihood of direct HPG axis inhibition by PRL. The tricyclic antidepressants have also been shown to increase PRL levels in some studies but not in others. The exception is the tricyclic antidepressant clomipramine, which profoundly increases PRL levels and may depress semen quality. Other antidepressants modulating synaptic levels of serotonin, norepinephrine, and/or dopamine may have toxicity similar to SSRIs, but most have not been evaluated. In limited studies, norepinephrine-dopamine reuptake inhibitors (NDRIs) and serotonin agonist/reuptake inhibitors (SARIs) have had minimal effects on PRL levels and on sexual side effects. Antipsychotic medications increase PRL, decrease testosterone, and increase sexual side effects, including ejaculatory dysfunction. The greatest evidence is for chlorpromazine, haloperidol, reserpine, risperidone, and thioridazine, with less effects seen with aripiprazole and clozapine. Remarkably few studies have looked at antipsychotic effects on semen quality, and this is an important knowledge gap in reproductive pharmacology. Lithium increases PRL and LH levels and decreases testosterone although this is informed by few studies. The anticonvulsants, many used for other indications, generally decrease free or bioavailable testosterone with variable effects on the other reproductive hormones. Valproate, carbamazepine, oxcarbazepine, and levetiracetam decrease semen quality; other anticonvulsants have not been investigated for this adverse reaction. Studies are required evaluating endpoints of pregnancy and offspring health for psychotropic medications.

Treatment of hypopituitarism in patients receiving antiepileptic drugs

Evidence suggests that there may be drug interactions between antiepileptic drugs and hormonal therapies, which can present a challenge to endocrinologists dealing with patients who have both hypopituitarism and neurological diseases. Data are scarce for this subgroup of patients; however, data for the interaction of antiepileptic drugs with the pituitary axis have shown that chronic use of many antiepileptic drugs, such as carbamazepine, oxcarbazepine, and topiramate, enhances hepatic cytochrome P450 3A4 (CYP3A4) activity, and can decrease serum concentrations of sex hormones. Other antiepileptic drugs increase sex hormone-binding globulin, which reduces the bioactivity of testosterone and estradiol. Additionally, the combined oestrogen-progestagen contraceptive pill might decrease lamotrigine concentrations, which could worsen seizure control. Moreover, sex hormones and their metabolites can directly act on neuronal excitability, acting as neurosteroids. Because carbamazepine and oxcarbazepine can enhance the sensitivity of renal tubules, a reduction in desmopressin dose might be necessary in patients with central diabetes insipidus. Although the effects of antiepileptic drugs in central hypothyroidism have not yet been studied, substantial evidence indicates that several antiepileptic drugs can increase thyroid hormone metabolism. However, although it is reasonable to expect a need for a thyroxine dose increase with some antiepileptic drugs, the effect of excessive thyroxine in lowering seizure threshold should also be considered. There are no reports of significant interactions between antiepileptic drugs and the efficacy of human growth hormone therapy, and few data are available for the effects of second-generation antiepileptic drugs on hypopituitarism treatment.

Toxicological assessment of drugs that affect the endocrine system in puberty-related disorders

INTRODUCTION

Toxicologists must ensure that clinical risk-to-benefit analysis should be made both for genders and age groups, with any treatment. Puberty concerns physiological changes leading to organism's maturation. Pubertal growth disorders are increasing in last decades: besides causing physical and psychological distress, they may signal underlying endocrine-metabolic abnormalities with serious health consequences later on. Therapeutic approaches for some health conditions in childhood and adolescence are considered.

AREAS COVERED

The authors discuss how some diseases and treatments can impact pubertal growth. The authors look at particular immunological disorders such as asthma and how both the disease and treatment affects pubertal growth. They also discuss how the provision of available data can help to assess the dose-response of the drug, in these cases, and minimize the chance of side effects. The authors also discuss pediatric inflammatory bowel disease and how both the disease and treatment can mitigate the growth delay. Last, but not least, the authors discuss how the effects of the drugs used in the treatment of psychiatric disorders may accentuate endocrine issues in juvenile patients. Hyperprolactinemia induction by some antipsychotics is highlighted as an example.

EXPERT OPINION

Appropriate risk-benefit analysis of drugs prescribed during childhood and adolescence and intended to be used in the long term is required. Furthermore, future treatment strategies and safer compounds development should be supported by the knowledge of mechanisms underlying adverse side effects in pubertal growth and development.

Neuroendocrine considerations in the treatment of men and women with epilepsy

Complex, multidirectional interactions between hormones, seizures, and the medications used to control them can present a challenge for clinicians treating patients with epilepsy. Many hormones act as neurosteroids, modulating brain excitability via direct binding sites. Thus, changes in endogenous or exogenous hormone levels can affect the occurrence of seizures directly as well as indirectly through pharmacokinetic effects that alter the concentrations of antiepileptic drugs. The underlying structural and physiological brain abnormalities of epilepsy and the metabolic activity of antiepileptic drugs can adversely affect hypothalamic and gonadal functioning. Knowledge of these complex interactions has increased and can now be incorporated in meaningful treatment approaches for men and women with epilepsy.

Antiepileptic drugs, sex hormones, and PCOS

Reproductive endocrine dysfunction in women with epilepsy is an important issue, and in recent years there is growing evidence to support the effect on sex hormones of both epilepsy per se and various antiepileptic drugs (AEDs). Focal epileptic discharges from the temporal lobe may have a direct influence on the function of the hypothalamic-pituitary axis, thereby altering the release of sex steroid hormones. The role of laterality and severity of epilepsy is still conflicting. The use of the liver enzyme-inducing AEDs--such as phenobarbital, phenytoin, and carbamazepine--can increase serum sex hormone-binding globulin concentrations, leading to diminished bioactivity of testosterone (T) and estradiol. Valproic acid, an enzyme inhibitor, has been associated with the occurrence of reproductive endocrine disorders characterized by high serum T, free androgen index, androstenedione, dehydroepiandrosterone sulfate concentrations, and with polycystic changes in ovaries and menstrual disorders. A better understanding of the effects of AEDs on sex hormones is key to selecting the appropriate AEDs and is crucial for reproductive health in female patients.

Epilepsy, sex hormones and antiepileptic drugs in female patients

Women with epilepsy have a higher incidence of reproductive endocrine disorders than the general female population. These alterations include polycystic ovary syndrome, hyperandrogenemia, infertility, hypothalamic amenorrhea and hyperprolactinemia. Reproductive dysfunction is attributed both to epilepsy itself and to antiepileptic drugs (AEDs). Focal epileptic discharges from the temporal lobe may have a direct influence on the function of the hypothalamic-pituitary axis, thus altering the release of sex steroid hormones, including the production of luteinizing hormone, follicle-stimulating hormone, gonadotropin-releasing hormone and prolactin. AEDs may modulate hormone release from the hypothalamic-pituitary-gonadal axis and they may alter the metabolism of sex hormones and their binding proteins. Hepatic enzyme-inducing AEDs, such as carbamazepine and phenytoin, may be most clearly linked to altered metabolism of sex steroid hormones, but valproic acid, an enzyme inhibitor, has also been associated with a frequent occurrence of polycystic ovary syndrome and hyperandrogenism in women with epilepsy. Therefore, treatment of epilepsy and selection of AEDs are important for reproductive health in female patients. The aim of the present review is to critically evaluate the recently published data concerning the interactions between sex hormones, epilepsy and AEDs.

Effect of antiepileptic drugs on reproductive endocrine function in individuals with epilepsy

It is well known that epilepsy, antiepileptic drugs (AEDs), and the reproductive system have complex interactions. Fertility is lower in both men and women with epilepsy than in the general population. Moreover, reproductive endocrine disorders are more common among patients with epilepsy than among the population in general. These disorders have been attributed both to epilepsy itself and to use of AEDs. The use of the liver enzyme-inducing AEDs phenobarbital, phenytoin and carbamazepine increases serum sex hormone-binding globulin (SHBG) concentrations in both men and women with epilepsy. Over time, the increase in serum SHBG levels leads to diminished bioactivity of testosterone and estradiol, which may result in diminished potency in men and menstrual disorders in some women, and thus to reduced fertility. Liver enzyme-inducing AEDs also reduce the efficacy of oral contraceptives. Valproic acid medication may have effects on serum androgen concentrations and it reduces serum follicle stimulating hormone levels in men with epilepsy. However, the clinical significance of valproic acid-related reproductive endocrine changes in men is unknown. On the other hand, in women, use of valproic acid appears to be associated with a frequent occurrence of reproductive endocrine disorders characterised by polycystic changes in the ovaries, high serum testosterone concentrations (hyperandrogenism) and menstrual disorders. These disorders are especially common among women who have gained weight during valproic acid treatment. There are some discrepancies regarding the reported occurrence of reproductive endocrine disorders in women taking valproic acid for epilepsy. However, most studies also including patients receiving valproic acid for other reasons than epilepsy, and studies in different non-epileptic animal models, have shown an association between valproic acid medication and hyperandrogenism and related reproductive endocrine disorders. From a practical point of view, the length of the menstrual cycles and bodyweight should be monitored in women with epilepsy after commencement of treatment with valproic acid. A serum testosterone assay is helpful in following the possible biochemical endocrine changes. Ultrasonography of the ovaries (preferably transvaginal) is indicated if clinical assessment and serum testosterone measurement imply that there is a clinically significant valproic acid-related reproductive endocrine problem. That would be the case if the menstrual cycles were irregular or prolonged (usually >35 days) and serum testosterone levels elevated, especially with associated weight gain. The endocrine effects of the new AEDs have not been widely studied. However, it seems they may offer an alternative if reproductive endocrine problems emerge during treatment with the older AEDs.

Predictors of ovulatory failure in women with epilepsy

Women with epilepsy (WWE) are at increased risk for reproductive disorders. This study was designed to evaluate whether WWE are more likely to have anovulatory cycles and to assess the relative association of the epilepsy syndrome category and antiepileptic drugs (AEDs) to ovulatory dysfunction. Subjects included women aged 18 to 40 years not receiving hormones. Women without epilepsy (23 controls) and women with localization-related epilepsy (LRE, n = 59) or idiopathic (primary) generalized epilepsy (IGE, n = 35) receiving either a cytochrome P450 enzyme (cP450) inducing AED (carbamazepine, phenytoin, and phenobarbital), a cP450 inhibiting AED (valproate), or an AED that does not alter cP450 enzymes (lamotrigine and gabapentin) in monotherapy for 6 months or more were followed for three menstrual cycles. A transvaginal ovarian ultrasound was obtained. Endocrine and metabolic variables were measured and luteinizing hormone sampled over 8 hours on days 2 to 5 of one cycle. Anovulatory cycles occurred in 10.9% of cycles in controls, 14.3% of cycles with LRE, and 27.1% of cycles with IGE. Of women using valproate currently or within the preceding 3 years, 38.1% had at least one anovulatory cycle in contrast with 10.7% of women not using valproate within the preceding 3 years. Predictors of ovulatory failure included IGE syndrome, use of valproate currently or within 3 years, high free testosterone, and fewer numbers of luteinizing hormone pulses, but not polycystic-appearing ovaries. WWE are more likely to experience anovulatory menstrual cycles and the effects of epilepsy syndrome, and AED therapy may be additive. Women with IGE receiving valproate were at highest risk for anovulatory cycles, polycystic-appearing ovaries, elevated body mass index, and hyperandrogynism. WWE with anovulatory cycles may have no other signs of reproductive dysfunction. Therefore, clinicians must be alert to this potential complication of epilepsy.

Reproductive dysfunction in women with epilepsy: recommendations for evaluation and management

BACKGROUND

Epilepsy is commonly associated with reproductive endocrine disorders. These include polycystic ovary syndrome (PCOS), isolated components of this syndrome such as polycystic ovaries, hyperandrogenaemia, hypothalamic amenorrhoea, and functional hyperprolactinaemia.

OBJECTIVE

To summarise the currently known relations between epilepsy and reproductive endocrine disorders.

METHODS

A review of clinical experience and published reports.

RESULTS

The most likely explanations for endocrine disorders related to epilepsy or antiepileptic drugs are: (1) a direct influence of the epileptogenic lesion, epilepsy, or antiepileptic drugs on the endocrine control centres in the brain; (2) the effects of antiepileptic drugs on peripheral endocrine glands; (3) the effects of antiepileptic drugs on the metabolism of hormones and binding proteins; and (4) secondary endocrine complications of antiepileptic drug related weight changes or changes of insulin sensitivity. Regular monitoring of reproductive function at visits is recommended, including questioning about menstrual disorders, fertility, weight, hirsutism, and galactorrhoea. Particular attention should be paid to patients on valproate and obese patients or those experiencing significant weight gain. Single abnormal laboratory or imaging findings without symptoms may not constitute a clinically relevant endocrine disorder. However, patients with these kinds of abnormalities should be monitored to detect the possible development of a symptomatic disorder associated with, for example, menstrual disorders or fertility problems.

CONCLUSIONS

If a reproductive endocrine disorder is found, antiepileptic drug treatment should be reviewed to ensure that it is correct for the particular seizure type and that it is not contributing to the endocrine problem. The possible benefits of a change in treatment must be balanced against seizure control and the cumulative side effect of alternative agents.

On the association between valproate and polycystic ovary syndrome

Recent studies by Isojärvi et al. have raised the issue of an increased incidence of polycystic ovary syndrome (PCOS) in women with epilepsy treated with valproate (VPA) and have proposed replacement with lamotrigine (LTG). Polycystic ovaries (PCO) are a common finding, with a prevalence >20% in the general population, and are easily detected by pelvic or vaginal ultrasonography, whereas PCOS is comparatively rare: few women with PCO have fully developed PCOS, which includes hirsutism, acne, obesity, hypofertility. hyperandrogenemia, and menstrual disorders. From an extensive review of the current literature, it appears that there are no reliable data on the actual prevalence of PCOS in normal women and in women with epilepsy. The pathogenesis of PCO is multifactorial, including genetic predisposition and the intervention of environmental factors, among which weight gain and hyperinsulinism with insulin resistance may play a part. The roles of central (hypothalamic/pituitary), peripheral, and local ovarian factors are still debated. PCO and PCOS appear to be more frequent in women with epilepsy, but there are no reliable data showing a greater prevalence after VPA. The recent studies by Isojärvi et al. may have been biased by the retrospective selection of patients. To date, there is no reason to contraindicate the use of VPA in women with epilepsy. However, patients should be informed about the risk of weight gain and its consequences.

The effect of seizures and kindling on reproductive hormones in the rat

Reproductive dysfunction and endocrine disorders are common among both women and men with epilepsy, and, in particular, with temporal lobe epilepsy. In clinical studies, it is hard to separate the effects of seizures from the effects of medication and life style. Studies in rodents, however, suggest that seizures per se can contribute to reproductive dysfunction. In female rats, generalized seizures disrupt normal ovarian cyclicity in adults, and repeated electroshock seizures delay the onset of puberty in juveniles. Right amygdala kindling in adult female rats causes acyclicity, the development of polycystic ovaries and premature aging of the hypothalamic-pituitary neuroendocrine axis, leading to chronic anovulation and continuous estrogen exposure. In adult male rats, repeated electroshock seizures result in transient hypogonadism, characterized by decreased serum testosterone levels and lowered gonadal tissue weight. In contrast, right amygdala kindling increases serum testosterone, estradiol levels and gonadal weight. These findings suggest that reproductive dysfunction in women and men with epilepsy may result from recurrent seizure activity, due to seizure-related interference with the normal functions of the hypothalamic-pituitary-gonadal axis.

Partial and generalized seizures affect reproductive physiology differentially in the male rat

PURPOSE

Reproductive dysfunction and endocrine disorders occur frequently among men with epilepsy. This study tested the hypothesis that focal limbic seizures and generalized seizures may both contribute to reproductive dysfunction.

METHODS

The rat kindling model was used to mimic focal limbic seizures. Kindling electrodes were placed in the basolateral amygdala. Male rats were either intact, gonadectomized (GDX) or GDX + testosterone (T) replaced and then kindled. Controls were left intact and sham-kindled. Maximal electroconvulsive shock (MES) treatment was used to model generalized seizures, by using eight stimulations, one every other day, for 2.5 weeks. Animals were killed either 3 h or 6 weeks after MES treatment to determine short- and long-term effects.

RESULTS

Kindled seizures resulted in an increase in serum testosterone, estradiol, and prolactin in intact males, accompanied by a significant increase in testis, epididymis, and pituitary weight, as well as a significant decrease in prostate weight. MES treatment caused a short-term reduction in serum testosterone and testis, epididymis, and prostate weight. All parameters were restored to control values within 6 weeks of the last MES seizure, with the exception of pituitary weight and serum prolactin, which remained significantly elevated 6 weeks after MES treatment.

CONCLUSIONS

Our results indicate that both focal limbic (amygdaloid) seizures and generalized MES seizures disturb normal reproductive physiology in the male rat. Amygdaloid-kindled seizures have mixed effects on different parameters of reproductive function, whereas MES seizures induce a transient hypogonadal state. These results suggest that reproductive dysfunction in men with epilepsy may result from seizure-related interference with the normal functions of the hypothalamic-pituitary-testicular axis.

Limbic seizures alter reproductive function in the female rat

PURPOSE

Reproductive dysfunction and endocrine disorders are common among women with temporal lobe epilepsy. This study used the kindled rat model to test the hypothesis that limbic seizures directly contribute to reproductive dysfunction.

METHODS

Kindling electrodes were implanted in the basolateral amygdala in adult female rats. Females were kindled by either brief, daily, suprathreshold stimulations with a bipolar electrode or sham-kindled (controls). Electrographic and behavioral seizures were monitored. Estrous cycles also were monitored with daily vaginal smears.

RESULTS

Seizures arrested ovarian cyclicity in all (n = 42) kindled animals, the rats exhibiting persistent vaginal cornification (PVC). In these animals PVC was associated with high serum estradiol, increased pituitary weight, and polyfollicular ovaries consisting of many cystic follicles, as well as follicles in various stages of growth and atresia. In 93% of females, this effect occurred after the development of stage 5 motor seizures, when focal seizures had secondarily generalized. In contrast, only five (21%) of 24 sham-kindled controls exhibited PVC. A single injection of progesterone (P4) temporarily restored cyclicity in five (18%) of 28 kindled females exhibiting PVC. In contrast, P4 administration restored cyclicity in all five sham-kindled controls that had spontaneously stopped cycling. P4 treatment to kindled females in PVC resulted in a different endocrine profile than that in non-P4-treated, kindled rats in PVC. P4-treated rats had high serum estradiol, testosterone, and prolactin levels; they showed an increase in pituitary weight; and their ovaries contained numerous corpora lutea and cystic follicles surrounded by markedly overdeveloped thecal cell layers.

CONCLUSIONS

Seizures initiated in the amygdala result in impairment of the hypothalamic-pituitary axis, resulting in loss of ovarian cyclicity.

Effects of antiepileptic drugs on hormones

A hormone is an intrinsic substance carried via the blood to a target organ which is then functionally stimulated. Similar to extrinsically administered medications, the metabolism and function of the hormones may be altered by antiepileptic drugs (AEDs). The proposed mechanisms are (a) enhanced metabolism (natural steroids, synthetic steroids, e.g., decadron and birth control pills, thyroxine, and vitamin D3), (b) altered protein bonding (thyroxine, sex hormones), (c) impaired release into the systemic circulation (calcitonin, insulin, vitamin K clotting factors) and (d) altered end-organ effect. The AEDs most likely to interact with hormones are barbiturates, carbamazepine, and phenytoin.

Sexual dysfunction in epilepsy

Sexual dysfunction may arise more frequently in men and women with epilepsy than with other chronic illnesses, manifesting primarily as diminished sexual desire and potency. Studies using retrospective self-report of sexual attitude and behavior find an incidence of sexual dysfunction ranging from 14-66%. Sexual dysfunction may be more common in partial than in generalized epilepsies. Sexual dysfunction in epilepsy may result from a disturbance in social or psychological factors affecting sexual responsiveness. Alternatively, epileptiform discharges may disrupt the function of structures mediating sexual behavior, particularly the limbic cortex, or alter the release of hypothalamic or pituitary hormones. Antiepileptic drugs modulate hormone release from the hypothalamic-pituitary-gonadal axis and may have direct inhibitory effects on sexual behavior. Evidence both supports and refutes each of these etiologies in the sexual dysfunction seen with epilepsy. Specific evaluation and treatment protocols for patients with sexual dysfunction are available.

Serum steroid hormones and pituitary function in female epileptic patients during carbamazepine therapy

Ten regularly menstruating women with epilepsy were studied in a 12-month prospective follow-up study to evaluate the short-term effects of carbamazepine (CBZ) on serum sex hormone balance and pituitary function. Thirteen female epilepsy patients receiving long-term CBZ monotherapy (mean medication duration 5.3 years) were also studied. Controls were 17 regularly menstruating healthy volunteers. Untreated patients had higher free testosterone (FT) and luteinizing hormone (LH) serum concentrations than control subjects, whereas the other parameters did not differ between these two groups. However, serum sex hormone binding globulin (SHBG) levels increased and dehydroepiandrosterone sulfate (DHEAS) levels decreased during CBZ treatment. Although calculated free androgen index (FAI) decreased during CBZ therapy, the directly measured FT levels remained unaltered. These changes were found after 2 months and continued after 12 months of CBZ treatment. Moreover, patients with long-term CBZ also had high SHBG levels, low serum DHEAS levels, and low FAI values. Basal LH serum levels decreased during the first year of CBZ treatment and luteinizing hormone-releasing hormone (LH-RH)-stimulated LH concentrations were lower after 2 months of CBZ treatment. Although the serum basal follicle-stimulating hormone (FSH) and prolactin (PRL) levels were unaffected during the first year of CBZ therapy, the LH-RH-stimulated FSH concentrations and metoclopramide (MC)-stimulated PRL concentrations were lower after 12 months of CBZ treatment than before CBZ. Both basal and stimulated gonadotropin and PRL serum levels of long-term CBZ patients were unaffected. No changes were found in estradiol (E2), testosterone (T), or cortisol (C) serum concentrations during short or long-term CBZ treatment.(ABSTRACT TRUNCATED AT 250 WORDS)