Antiepileptic Drug Therapy for Status Epilepticus

Status epilepticus (SE) is one of the most serious neurologic emergencies. SE is a condition that encompasses a broad range of semiologic subtypes and heterogeneous etiologies. The treatment of SE primarily involves the management of the underlying etiology and the use of antiepileptic drug therapy to rapidly terminate seizure activities. The Drug Committee of the Korean Epilepsy Society performed a review of existing guidelines and literature with the aim of providing practical recommendations for antiepileptic drug therapy. This article is one of a series of review articles by the Drug Committee and it summarizes staged antiepileptic drug therapy for SE. While evidence of good quality supports the use of benzodiazepines as the first-line treatment of SE, such evidence informing the administration of second- or third-line treatments is lacking; hence, the recommendations presented herein concerning the treatment of established and refractory SE are based on case series and expert opinions. The choice of antiepileptic drugs in each stage should consider the characteristics and circumstances of each patient, as well as their estimated benefit and risk to them. In tandem with the antiepileptic drug therapy, careful searching for and treatment of the underlying etiology are required.

Antiepileptic Drugs and Liver Disease

Acute, symptomatic seizures or epilepsy may complicate the course of hepatic disease. Choosing the most appropriate antiepileptic drug in this setting represents a difficult challenge, as most medications are metabolized by the liver. This article focuses on the acute and chronic treatment of seizures in patients with advanced liver disease and reviews the hepatotoxic potential of specific antiepileptic drugs. Newer antiepileptic drugs without, or with minimal, hepatic metabolism, such as levetiracetam, lacosamide, topiramate, gabapentin, and pregabalin should be used as first-line therapy. Medications undergoing extensive hepatic metabolism, such as valproic acid, phenytoin, and felbamate should be used as drugs of last resort. In special circumstances, as in patients affected by acute intermittent porphyria, exposure to most antiepileptic drugs could precipitate attacks. In this clinical scenario, bromides, levetiracetam, gabapentin, and vigabatrin constitute safe choices. For the treatment of status epilepticus, levetiracetam and lacosamide, available in intravenous preparations, are good second-line therapies after benzodiazepines fail to control seizures. Hepatotoxicity is also a rare and unexpected side effect of some antiepileptic drugs. Drugs such as valproic acid, phenytoin, and felbamate, have a well-recognized association with liver toxicity. Other antiepileptic drugs, including phenobarbital, benzodiazepines, ethosuximide, and the newer generations of antiepileptic drugs, have only rarely been linked to hepatotoxicity. Thus physicians should be mindful of the pharmacokinetic profile and the hepatotoxic potential of the different antiepileptic drugs available to treat patients affected by liver disease.

Treatment of Established Status Epilepticus

Status epilepticus is the most severe form of epilepsy, with a high mortality rate and high health care costs. Status epilepticus is divided into four stages: early, established, refractory, and super-refractory. While initial treatment with benzodiazepines has become standard of care for early status epilepticus, treatment after benzodiazepine failure (established status epilepticus (ESE)) is incompletely studied. Effective treatment of ESE is critical as morbidity and mortality increases dramatically the longer convulsive status epilepticus persists. Phenytoin/fosphenytoin, valproic acid, levetiracetam, phenobarbital, and lacosamide are the most frequently prescribed antiseizure medications for treatment of ESE. To date there are no class 1 data to support pharmacologic recommendations of one agent over another. We review each of these medications, their pharmacology, the scientific evidence in support and against each in the available literature, adverse effects and safety profiles, dosing recommendations, and limitations of the available evidence. We also discuss future directions including the established status epilepticus treatment trial (ESETT). Substantial further research is urgently needed to identify these patients (particularly those with non-convulsive status epilepticus), elucidate the most efficacious antiseizure treatment with head-to-head randomized prospective trials, and determine whether this differs for convulsive vs. non-convulsive ESE.