Antiepileptic Drugs Under Investigation for Treatment of Focal Epilepsy

Medical Management in Focal versus Generalized Epilepsy

About 70% of children with new-onset epilepsy have the potential to become seizure-free on antiepileptic drug (AED) monotherapy with appropriately selected first-line medication. In ideal world, physician is expected to achieve best possible seizure control without impacting the quality of life. There is rapid increase in number of AEDs available over last couple of decades. Although not necessarily all of them are superior to old generation drugs in terms of seizure control, certainly there is change in landscape from perspective of tolerability and side-effect profile. Physicians must therefore be familiar with safety, tolerability, therapeutic effects, synergistic combinations as well as AEDs to avoid in specific circumstances. The article attempts to give general overview of available AEDs under broad umbrella of effectiveness against focal and generalized seizures as well as drugs with “broad spectrum.” The emergence of newer AEDs with broad spectrum and favorable side-effect profile is welcome. However, the future lies in better understanding of underlying diverse pathophysiology of clinical symptom “epilepsy” and developing new compounds acting on molecular targets as well as individualizing therapy. Technological advances in molecular genetics research are bringing precision medicine to the fore.

A Volumetric Absorptive Microsampling Technique to Monitor Cannabidiol Levels in Epilepsy Patients

Purpose: Interest in cannabis-based therapies has recently increased, due to the availability of cannabidiol (CBD) for the treatment of epilepsy without psychoactive effects. Therapeutic drug monitoring can prevent drug interactions and minimize drug toxicity. We evaluated a volumetric absorptive microsampling (VAMS) method combined with LC-MS/MS (liquid chromatography coupled to tandem mass spectrometry) for the quantification of CBD blood levels in patients with refractory epilepsy.

Methods: Prospective observation of patients with Dravet syndrome receiving open-label, add-on GW-purified CBD (Epidyolex^®) at different doses. CBD plasma samples were obtained from venipuncture and LC-MS/MS was used to measure CBD in venous and capillary blood samples collected by VAMS.

Results: We enrolled five patients with a mean age of 13 (range: 4–27) years. CBD levels measured by VAMS on capillary blood did not differ from CBD levels measured in plasma by venipuncture (R² > 0.93).

Conclusion: This proof-of-concept study suggests that VAMS allows monitoring of CBD plasma levels and can offer valuable support for personalized therapy in refractory epilepsy.

Pharmacodynamics and common drug-drug interactions of the third-generation antiepileptic drugs

INTRODUCTION

Anticonvulsants that belong to the third generation are considered as 'newer' antiepileptic drugs, including: eslicarbazepine acetate, lacosamide, perampanel, brivaracetam, rufinamide and stiripentol. Areas covered: This article reviews pharmacodynamics (i.e. mechanisms of action) and clinically relevant drug-drug interactions of the third-generation antiepileptic drugs. Expert opinion: Newer antiepileptic drugs have mechanisms of action which are not shared with the first and the second generation anticonvulsants, like inhibition of neurotransmitters release, blocking receptors for excitatory amino acids and new ways of sodium channel inactivation. New mechanisms of action increase chances of controlling forms of epilepsy resistant to older anticonvulsants. Important advantage of the third-generation anticonvulsants could be their little propensity for interactions with both antiepileptic and other drugs observed until now, making prescribing much easier and safer. However, this may change with new studies specifically designed to discover drug-drug interactions. Although the third-generation antiepileptic drugs enlarged therapeutic palette against epilepsy, 20-30% of patients with epilepsy is still treatment-resistant and need new pharmacological approach. There is great need to explore all molecular targets that may directly or indirectly be involved in generation of seizures, so a number of candidate compounds for even newer anticonvulsants could be generated.

The long-term prognosis of epilepsy patients with medically treated over a period of eight years in Turkey

Objective:

The aim of this study was to investigate the effect of demographic and clinical characteristics on temporal changes in seizure control and frequency in medically treated epilepsy patients to guide treatment modalities.

Methods:

We retrospectively analyzed the association between clinical and demographic characteristics and seizure frequency in 1329 epilepsy patients who were followed up at an outpatient clinic for one to eight years, 2008-2015..

Results:

Younger age at first seizure (p = 0.0465) and a long disease duration (p = 0.0406) had a negative effect on seizure control in all the epilepsy patients. Febrile convulsions (FCs) (p > 0.0001), perinatal risk (PNR) (p > 0.0002), a family history of epilepsy (FHE) (p > 0.0016), antiepileptic drug (AED) use (p > 0.001), mental retardation (MR) (p > 0.001), and psychiatric disorders (p > 0.0478) were prognostic indictors of temporal changes in seizure frequency. The presence of PNR (p = 0.0416), age at onset of epilepsy (p = 0.034), central nervous system infection (CNSI) (p = 0.04), and AEDs number (p = 0.0282) were prognostic indicators of not remaining seizure free for one year. In those with partial epilepsy, a trauma history (p = 0.05), a longer epilepsy duration (p = 0.0057), and FHE (p = 0.0466) increased the frequency of seizures, whereas cerebrovascular event (CVE) history decreased the seizure frequency (p = 0.0413). In addition, FHE (p = 0.0438) and psychotic disorders (p = 0.0416) increased generalized seizures frequency.

Conclusion:

In all the epilepsy patients, a younger age at onset and longer duration of epilepsy were associated with a poor prognosis. The presence of PNR, age at onset of epilepsy, CNSI, and AEDs numbers were prognostic indicators of not remaining seizure free for one year. Increasing AEDs number was not effective in controlling seizures in partial epilepsy, but it was effective in controlling seizures in generalized epilepsy.