Patterns of antiepileptic drugs use in epileptic pediatric patients in Jordan

Current role of carbamazepine and oxcarbazepine in the management of epilepsy

Epilepsy is one of the most common neurological disorders, affecting approximately 50 million people worldwide. Despite a dramatic increase in treatment options over the past 30 years, it still ranks fourth in the world's disease burden. There are now close to 30 antiepileptic drugs (AEDs), with more than two thirds introduced to the market after carbamazepine (CBZ) and one third after its derivative, oxcarbazepine (OXC). Following the introduction of these newer AEDs, the role of CBZ and OXC in the therapeutic armamentarium for seizure control and effective epilepsy management needs to be reviewed. The main guidelines list both CBZ and OXC as first-line options or second-line alternatives for the treatment of focal-onset epilepsy and primary generalized tonic-clonic seizures. While evidence suggests that overall AEDs have similar efficacy, some newer AEDs may be better tolerated than CBZ. In line with this, there have been changes in treatment patterns, with many variations across different countries. However, CBZ remains among the two or three most prescribed drugs for focal epilepsy in many countries, and is widely used across Europe, Africa, South America, and Asia, where it represents a good compromise between cost, availability, and effectiveness. OXC is among the first-choice options for the initial treatment of focal-onset seizures in several countries, including the US and China, where the oral suspension is commonly prescribed. This review provides guidance on the optimal use of these two drugs in clinical practice, including in children, the elderly, and in pregnancy.

Frequency of antiepileptic drugs and response change in pediatric patients receiving 2 or more antiepileptic drugs

OBJECTIVE

To investigate the frequency of changes in antiepileptic drugs (AEDs) use, as well as concomitant changes in the degree of seizure control in pediatric patients, who are receiving 2 or more AEDs.

METHODS

A prospective follow-up study at Jordan University Hospital`s pediatric neurology clinics was conducted on epileptic pediatric patients receiving at least 2 AEDs between December 2013 and April 2014. Patients were followed for 12 months.

RESULTS

A total of 82 patients were included, with a mean age of 7.2+/- 4.7 years. The mean number of AEDs received by patients at enrollment was 2.4+/-0.6, and 2.5+/-0.7 after follow-up. Most patients (63.4%) experienced no change in seizure control, and the majority reported at least one adverse drug reaction. Most patients received lower doses than recommended, both at the beginning and end of the study. During the year, only 3 patients (4%) were eligible for dose tapering, which would then be converted to monotherapy. Follow-up appointments average was 4.2+/-2.9 visits/patients in one year. The frequency of medication changes and dose adjustment was very low, about one-third (29.3%) of patients requiring no change in AEDs during any follow-up visits.

CONCLUSION

During the one year follow-up study, most patients on polytherapy maintained their level of response to the AEDs, with minimal changes in their regimen despite frequent follow-up visits. Only a small percent could be converted to AEDs monotherapy.

Pharmacogenetics of carbamazepine

Carbamazepine (CMZ) is a drug from the group of anticonvulsants, similar in chemical structure to tricyclic antidepressants. CMZ is widely used for mental disorders and neurological diseases. The lecture discusses the safety of CMZ in respect to personalized medicine, while considering the pharmacogenetic profile of the patient.

The authors declare about the absence of conflict of interest with respect to this publication. All authors contributed equally to this article.

Pharmacokinetics and Pharmacogenetics of Carbamazepine in Children

Although carbamazepine is one of the oldest anticonvulsant drugs, it is still heavily utilized for treatment of epilepsy in children. The aim of this article was to review the current knowledge about pharmacokinetics and pharmacogenetics of carbamazepine in children. The literature for this review was systematically searched for in the MEDLINE and SCINDEKS databases. Oral bioavailability of carbamazepine in children is about 75-85%, and it is approximately 75-85% bound to plasma proteins. Apparent volume of distribution is 1.2-1.9 l/kg and total clearance between 0.05 and 0.1 l/h/kg. Pharmacokinetics of carbamazepine in children is age and body weight dependent and highly variable due to influence of dosing regimen and co-medication. The current evidence on the importance of pharmacogenetics for carbamazepine efficacy and safety in children supports the association of PXR*1B, HNF4a rs2071197, CYP1A2*1F, ABCC2 1249G>A, and PRRT2 c.649dupC with either pharmacokinetics or pharmacodynamics of carbamazepine. The importance of human leukocyte antigen (HLA) typing for prediction of adverse drug reactions to carbamazepine in children is also confirmed. Both genetic and environmental factors are responsible for shaping pharmacokinetics and pharmacodynamics of carbamazepine in children. To ensure safe and effective use of carbamazepine in this population, physicians should adjust dosing regimen according to existing pattern of genetic and environmental influences.

Anti-epileptic drug utilisation in paediatrics: a systematic review

OBJECTIVES

This study aims to determine global anti-epileptic drug (AED) utilisation prevalence and describe utilisation trends in different countries.

METHODS

Databases Embase (1980-May 2017), Medline (1946-May 2017) and PubMed were searched for original research on AED utilisation. All paediatric national or regional database studies and surveys were included.

RESULTS

Twenty-one studies were identified. Five were excluded from the analysis as the data were collected before 2005, leaving 16 studies. Monotherapy regimen varied between 58% and 94% in different countries. In several of the studies, sodium valproate was the most frequently prescribed AED. However, there is a trend towards increasing utilisation of new-generation AEDs, particularly levetiracetam, in some countries.

CONCLUSION

Monotherapy was used in 58%-94%of patients. There is increasing utilisation of the new-generation AEDs, in particular lamotrigine, levetiracetam and topiramate. Old-generation AEDs are still used in the majority of patients. There is a need for up-to-date studies to determine the prevalence of AEDs in children.

Effect of early postnatal exposure to valproate on neurobehavioral development and regional BDNF expression in two strains of mice

Valproate has been used for over 30years as a first-line treatment for epilepsy. In recent years, prenatal exposure to valproate has been associated with teratogenic effects, limiting its use in women that are pregnant or of childbearing age. However, despite its potential detrimental effects on development, valproate continues to be prescribed at high rates in pediatric populations in some countries. Animal models allow us to test hypotheses regarding the potential effects of postnatal valproate exposure on neurobehavioral development, as well as identify potential mechanisms mediating observed effects. Here, we tested the effect of early postnatal (P4-P11) valproate exposure (100mg/kg and 200mg/kg) on motor and affective development in two strains of mice, SVE129 and C57Bl/6N. We also assessed the effect of early valproate exposure on regional BDNF protein levels, a potential target of valproate, and mediator of neurodevelopmental outcomes. We found that early life valproate exposure led to significant motor impairments in both SVE129 and C57Bl/6N mice. Both lines of mice showed significant delays in weight gain, as well as impairments in the righting reflex (P7-8), wire hang (P17), open field (P12 and P21), and rotarod (P25 and P45) tasks. Interestingly, some of the early locomotor effects were strain- and dose-dependent. We observed no effects of valproate on early markers of anxiety-like behavior. Importantly, early life valproate exposure had significant effects on regional BDNF expression, leading to a near 50% decrease in BDNF levels in the cerebellum of both strains of mice, while not impacting hippocampal BDNF protein levels. These observations indicate that postnatal exposure to valproate may have significant, and region-specific effects, on neural and behavioral development, with specific consequences for cerebellar development and motor function.