Epilepsy, antiepileptic drugs, and the risk of major cardiovascular events

OBJECTIVE

This study was undertaken to determine whether epilepsy and antiepileptic drugs (including enzyme-inducing and non-enzyme-inducing drugs) are associated with major cardiovascular events using population-level, routinely collected data.

METHODS

Using anonymized, routinely collected, health care data in Wales, UK, we performed a retrospective matched cohort study (2003-2017) of adults with epilepsy prescribed an antiepileptic drug. Controls were matched with replacement on age, gender, deprivation quintile, and year of entry into the study. Participants were followed to the end of the study for the occurrence of a major cardiovascular event, and survival models were constructed to compare the time to a major cardiovascular event (cardiac arrest, myocardial infarction, stroke, ischemic heart disease, clinically significant arrhythmia, thromboembolism, onset of heart failure, or a cardiovascular death) for individuals in the case group versus the control group.

RESULTS

There were 10 241 cases (mean age = 49.6 years, 52.2% male, mean follow-up = 6.1 years) matched to 35 145 controls. A total of 3180 (31.1%) cases received enzyme-inducing antiepileptic drugs, and 7061 (68.9%) received non-enzyme-inducing antiepileptic drugs. Cases had an increased risk of experiencing a major cardiovascular event compared to controls (adjusted hazard ratio = 1.58, 95% confidence interval [CI] = 1.51-1.63, p < .001). There was no notable difference in major cardiovascular events between those treated with enzyme-inducing antiepileptic drugs and those treated with non-enzyme-inducing antiepileptic drugs (adjusted hazard ratio = .95, 95% CI = .86-1.05, p = .300).

SIGNIFICANCE

Individuals with epilepsy prescribed antiepileptic drugs are at an increased risk of major cardiovascular events compared with population controls. Being prescribed an enzyme-inducing antiepileptic drug is not associated with a greater risk of a major cardiovascular event compared to treatment with other antiepileptic drugs. Our data emphasize the importance of cardiovascular risk management in the clinical care of people with epilepsy.

Vitamin D deficiency in a Portuguese epilepsy cohort: who is at risk and how to treat

The epilepsy-related risk factors for vitamin D deficiency, particularly the use of enzyme-inducing antiepileptic drugs (EIAEDs), and how to treat vitamin D deficiency in patients with epilepsy remain unclear. Our aims were to explore risk factors and the influence of EAIEDs in vitamin D status and to determine the efficacy of a daily dose of oral cholecalciferol (vitamin D3) in epileptic patients with vitamin D deficiency. Clinical data were collected and 25-hydroxyvitamin D (25(OH)D) serum levels were measured. All patients with vitamin D deficiency (25(OH)D ≤20 ng/mL) or insufficiency (25(OH)D from 21-29 ng/mL) were treated with 6,670 IU/day cholecalciferol for eight weeks and 25(OH)D was then remeasured. Descriptive and inferential statistics were employed. A total of 92 patients (44.6% males), with mean age of 41.0±14.8 years, were included. Measurements of 25(OH)D revealed that 79.3% patients had abnormal levels: 56.5% were vitamin D deficient and 22.8% were vitamin D insufficient. The statistically significant risk factors for vitamin D deficiency identified were: number of AEDs, treatment with EIAEDs, low sun exposure, high body mass index (BMI) and a high frequency of epileptic seizures. After treatment, 25(OH)D mean level increased by 98.99% (regardless of EIAED use or being overweight). In our sample, more than half of the adults with epilepsy showed 25(OH)D deficiency. Patients on EIAEDs had lower 25(OH)D levels. A daily dose of 6,670 IU cholecalciferol successfully led to the correction of 25(OH)D levels. A higher dose in obese patients or in patients taking EIAEDs may not be warranted and this should be considered in future guidelines for routine vitamin D deficiency treatment.

Drug interactions with solid tumour-targeted therapies

Drug interactions are an on-going concern in the treatment of cancer, especially when targeted therapies, such as tyrosine kinase inhibitors (TKI) or mammalian target of rapamycin (mTOR) inhibitors, are being used. The emergence of elderly patients and/or patients with both cancer and other chronic co-morbidities leads to polypharmacy. Therefore, the risk of drug-drug interactions (DDI) becomes a clinically relevant issue, all the more so as TKIs and mTOR inhibitors are essentially metabolised by cytochrome P450 enzymes. These DDIs can result in variability in anticancer drug exposure, thus favouring the selection of resistant cellular clones or the occurrence of toxicity. This review provides a comprehensive overview of DDIs that involve targeted therapies approved by the FDA for the treatment of solid tumours for more than 3 years (sorafenib, sunitinib, erlotinib, gefitinib, imatinib, lapatinib, everolimus, temsirolimus) and medicinal herb or drugs. This review also provides some guidelines to help oncologists and pharmacists in their clinical practice.

Phase 1 study of erlotinib HCl alone and combined with temozolomide in patients with stable or recurrent malignant glioma

The purpose of this study was to define the maximum tolerated dose of erlotinib and characterize its pharmaco-kinetics and safety profile, alone and with temozolomide, with and without enzyme-inducing antiepileptic drugs (EIAEDs), in patients with malignant gliomas. Patients with stable or progressive malignant primary glioma received erlotinib alone or combined with temozolomide in this dose-escalation study. In each treatment group, patients were stratified by coadministration of EIAEDs. Erlotinib was started at 100 mg orally once daily as a 28-day treatment cycle, with dose escalation by 50 mg/day up to 500 mg/day. Temozolomide was administered at 150 mg/m2 for five consecutive days every 28 days, with dose escalation up to 200 mg/m2 at the second cycle. Eightythree patients were evaluated. Rash, fatigue, and diarrhea were the most common adverse events and were generally mild to moderate. The recommended phase 2 dose of erlotinib is 200 mg/day for patients with glioblastoma multiforme who are not receiving an EIAED, 450 mg/day for those receiving temozolomide plus erlotinib with an EIAED, and at least 500 mg/day for those receiving erlotinib alone with an EIAED. Of the 57 patients evaluable for response, eight had a partial response (PR). Six of the 57 patients had a progression-free survival of longer than six months, including four patients with a PR. Coadministration of EIAEDs reduced exposure to erlotinib as compared with administration of erlotinib alone (33%-71% reduction). There was a modest pharmacokinetic interaction between erlotinib and temozolomide. The favorable tolerability profile and evidence of antitumor activity indicate that further investigation of erlotinib is warranted.