Effect of antiepileptic drug comedication on lamotrigine concentrations

The teratogenesis risk associated with antiseizure medication duotherapy in women with epilepsy

PURPOSE

To investigate rates of occurrence of pregnancies associated with a foetal malformation (FM pregnancy rates) following simultaneous intrauterine exposure to two antiseizure medications in 524 pregnancies in women with epilepsy from the Australian Pregnancy Register who were treated simultaneously with various combinations and dosages of two antiseizure medications (duotherapy).

RESULTS

FM pregnancy rates tended to be higher in those exposed simultaneously to two antiseizure medications, each of which was a statistically significant teratogen (valproate, topiramate, or carbamazepine), than when there was exposure to only one such teratogen. When there was exposure to only one such teratogen together with clonazepam or levetiracetam, for neither of which there was statistically significant evidence of heightened teratogenicity, the FM pregnancy rates also tended to be higher, but less so. When lamotrigine was the other component of the duotherapy with an established teratogen, FM pregnancy rates tended to be lower than that for the teratogen used as monotherapy.

CONCLUSION

Leaving aside issues in relation to seizure control, our data suggest that it would be best to avoid using established teratogenic antiseizure medications (carbamazepine, valproate and topiramate) in combination with each other due to the increased FM risks. When combining an established teratogenic medication with a less teratogenic one, i.e. lamotrigine, levetiracetam or clonazepam, lamotrigine appears to be the safer option.

Adverse Event Profiles of Antiseizure Medications and the Impact of Coadministration on Drug Tolerability in Adults with Epilepsy

BACKGROUND

Antiseizure medication (ASM) as monotherapy or in combination is the treatment of choice for most patients with epilepsy. Therefore, knowledge about the typical adverse events (AEs) for ASMs and other coadministered drugs (CDs) is essential for practitioners and patients. Due to frequent polypharmacy, it is often difficult to clinically assess the AE profiles of ASMs and differentiate the influence of CDs.

OBJECTIVE

This retrospective analysis aimed to determine typical AE profiles for ASMs and assess the impact of CDs on AEs in clinical practice.

METHODS

The Liverpool AE Profile (LAEP) and its domains were used to identify the AE profiles of ASMs based on data from a large German multicenter study (Epi2020). Following established classifications, drugs were grouped according to their mode of action (ASMs) or clinical indication (CDs). Bivariate correlation, multivariate ordinal regression (MORA), and artificial neural network (ANNA) analyses were performed. Bivariate correlation with Fisher's z-transformation was used to compare the correlation strength of LAEP with the Hospital Anxiety and Depression Scale (HADS) and Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) to avoid LAEP bias in the context of antidepressant therapy.

RESULTS

Data from 486 patients were analyzed. The AE profiles of ASM categories and single ASMs matched those reported in the literature. Synaptic vesicle glycoprotein 2A (SV2A) and voltage-gated sodium channel (VGSC) modulators had favorable AE profiles, while brivaracetam was superior to levetiracetam regarding psychobehavioral AEs. MORA revealed that, in addition to seizure frequency, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) modulators and antidepressants were the only independent predictors of high LAEP values. After Fisher's z-transformation, correlations were significantly lower between LAEP and antidepressants than between LAEP and HADS or NDDI-E. Therefore, a bias in the results toward over interpreting the impact of antidepressants on LAEP was presumed. In the ANNA, perampanel, zonisamide, topiramate, and valproic acid were important nodes in the network, while VGSC and SV2A modulators had low relevance for predicting relevant AEs. Similarly, cardiovascular agents, analgesics, and antipsychotics were important CDs in the ANNA model.

CONCLUSION

ASMs have characteristic AE profiles that are highly reproducible and must be considered in therapeutic decision-making. Therapy using perampanel as an AMPA modulator should be considered cautiously due to its relatively high AE profile. Drugs acting via VGSCs and SV2A receptors are significantly better tolerated than other ASM categories or substances (e.g., topiramate, zonisamide, and valproate). Switching to brivaracetam is advisable in patients with psychobehavioral AEs who take levetiracetam. Because CDs frequently pharmacokinetically interact with ASMs, the cumulative AE profile must be considered.

TRIAL REGISTRATION

DRKS00022024, U1111-1252-5331.

Analysis of the clinical characteristics of lamotrigine-induced haemophagocytic lymphohistiocytosis

WHAT IS KNOWN AND OBJECTIVE

Lamotrigine is currently known to be related to haemophagocytic lymphohistiocytosis (HLH). Knowledge regarding the association between HLH and lamotrigine is mainly based on case reports. The purpose of this study was to evaluate the clinical characteristics of lamotrigine-induced HLH.

METHODS

We collected literature from 1994 to 31 August 2020 in Chinese and English on HLH induced by lamotrigine for retrospective analysis.

RESULTS AND DISCUSSION

A total of 17 patients (12 men and 5 women) from 15 studies were included, with a median age of 29 years old (range 4-47). Symptoms of lamotrigine-induced HLH were reported to have occurred within 6-24 days following treatment initiation. Six cases reported doses that ranged from 25 mg every other day to 800 mg once daily. The major clinical features of lamotrigine-induced HLH are fever, cytopenia, rash and hyperferritinaemia. Bone marrow showed haemophagocytosis. Fifteen patients improved with drug discontinuation, and 2 patients eventually died.

WHAT IS NEW AND CONCLUSION

Hemophagocytic lymphohistiocytosis is a potentially serious adverse reaction to lamotrigine (LTG). Patients should be informed that if they experience any symptoms of HLH while taking lamotrigine, they should immediately seek medical attention.

Lamotrigine-induced neutropenia after high-dose concomitant initiation with phenytoin

Lamotrigine has been repeatedly reported to cause hematologic toxicities, which may be associated with high initial doses or excessive escalation. A 29-year-old lady experienced profound neutropenia after two weeks of lamotrigine high initial dose, started within two days of phenytoin. The too-early dose intensification may have produced lamotrigine-induced blood dyscrasia.

Lessons learned from the discovery of sodium valproate and what has this meant to future drug discovery efforts?

INTRODUCTION

The discovery of the anticonvulsant properties of valproic acid and the development of valproic acid/valproate to market authorization for specific epilepsy types and syndromes, as well as their repurposing for other indications, are illustrative examples of both the strengths and weaknesses of drug development strategies.

AREAS COVERED

This review summarizes and interprets the development and repurposing history of valproic acid/valproate. The article is based on articles, including original studies and systematic reviews obtained from PubMed, Scopus, EBSCO, SCIndeks and Google Scholar databases.

EXPERT OPINION

Random screening and careful observation of the experimental effects of tested substances were crucial for discovering the anticonvulsant effects of valproic acid, while rational drug design and clinical observation strategies led to repurposing valproic acid and valproate for bipolar disorder maintenance treatmentand prevention of migraine attacks. Early planning and feasibility studies of future clinical trials are essential for obtaining marketing authorization of new substances or new indications of old anticonvulsants. Significant progress has been made recently toward understanding, treatment and prevention of hepatotoxicity caused by valproic acid/valproate, making its long-term administration safer. There are ongoing efforts to repurpose valproic acid/valproate for augmentation with antipsychotic drugs for the treatment of schizophrenia.

Influence of genetic variants and antiepileptic drug co-treatment on lamotrigine plasma concentration in Mexican Mestizo patients with epilepsy

Genetic and nongenetic factors may contribute to lamotrigine (LTG) plasma concentration variability among patients. We simultaneously investigated the association of UGT1A1, UGT1A4, UGT2B7, ABCB1, ABCG2, and SLC22A1 variants, as well as antiepileptic drug co-treatment, on LTG plasma concentration in 97 Mexican Mestizo (MM) patients with epilepsy. UGT1A4*1b was associated with lower LTG dose-corrected concentrations. Patients with the UGT2B7-161T allele were treated with 21.22% higher LTG daily dose than those with CC genotype. Two novel UGT1A4 variants (c.526A>T; p.Thr185= and c.496T>C; p.Ser166Leu) were identified in one patient. Patients treated with LTG + valproic acid (VPA) showed higher LTG plasma concentration than patients did on LTG monotherapy or LTG + inducer. Despite the numerous drug-metabolizing enzymes and transporter genetic variants analyzed, our results revealed that co-treatment with VPA was the most significant factor influencing LTG plasma concentration, followed by UGT1A4*1b, and that patients carrying UGT2B7 c.-161T required higher LTG daily doses. These data provide valuable information for the clinical use of LTG in MM patients with epilepsy.

Development and validation of an improved HPLC-UV method for simultaneous determination of lamotrigine and oxcarbazepine and its active metabolite 10,11-dihydro-10-hydroxycarbazepine in human blood plasma and comparison with an UHPLC-MS/MS method

Lamotrigine (LTG) and oxcarbazepine (OXC) are first-line drugs for epilepsy treatment. Their large pharmacokinetics variabilities and relations between efficacy and toxicity and blood plasma concentration require routine monitoring for dose adjustment. In this study, we developed and validated a simple, accurate, and reliable method for simultaneous determination of LTG, OXC and 10,11-dihydro-10-hydroxycarbazepine (MHD) in human blood plasma by high-performance liquid chromatography-ultraviolet detection (HPLC-UV) with a simple one-step protein precipitation using methanol (1% acetic acid) and 15 min elution time under isocratic elution at 1 mL/min. Calibration range was 2.4 to 120 mg/L for LTG, OXC, and MHD. The intra-day and inter-day bias were − 8.84 to 4.18%, and the imprecision was less than 8.08% for all analytes. The internal standard (fluconazole) normalized recovery was 96.30 to 107.69% for LTG, 98.51 to 111.04% for MHD, and 95.04 to 109.86% for OXC. A total of 186 LTG samples and 25 MHD samples were used to evaluate the agreement between HPLC-UV and ultra-performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) by Passing-Bablok regression and Bland-Altman plot. The mean bias and the 95% limits of agreement (95% LOA) of the two measurements were 0.575 mg/L and − 1.238 to 2.387 mg/L for LTG (n = 186) and − 1.222 mg/L and − 8.271 to 5.827 mg/L for MHD (n = 25), which indicated the UV method was comparable with the MS method for LTG and MHD analysis.