Other Pharmacologic Therapy for Refractory Status Epilepticus

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Wasterlain : Table of Contents: Other Pharmacologic Therapy for Refractory Status Epilepticus : Introduction

Introduction

Most cases of status epilepticus (SE) remit with the first-line therapies discussed in this book. When status continues, however, doctors must turn to other therapies, the efficacies of which are less established. This chapter considers a miscellany of drug treatments not elsewhere described: propofol, inhaled anesthetics, etomidate, lidocaine, paraldehyde, magnesium, furosemide, and direct infusion of drugs at the seizure focus. The clinical characteristics of these drugs are described in Table 46.1. Midazolam is discussed in Chapter 49.

**Table 46.1 : Summary of clinical characteristics of the “miscellany treatments” for status epilepticus**
Drug	Safe and Efficacious	Special Considerations	Dosage and Regimen
Propofol	Yes	Probable need to push to coma-inducing doses	Loading dose: 1–2mg/kg.
Maintenance dose: Start at 2mg/kg/hr. Requires EEG monitoring with titration to burst suppression.
Subcoma doses: Continuous infusion. Start at 0.1mg/ kg/hr; titrate upward until seizure activity stops.
Inhaled anesthetics	Mixed reports	Need special apparatus for delivery; requires skilled anesthetist in attendance	Induction: Inhaled concentration of 1.5%–3.0%.
Maintenance dose: Dose should be titrated to burst suppression on EEG (generally will be in range of 0.8%–2.0% inhaled isoflurane concentration). Halothane may require mixing with N₂O to achieve burst suppression without loss of cardiac output.
Etomidate	Probably not	Inhibition of adrenocorticoid synthesis; requires exogenous	Loading dose (optional): 300µg/kg.
Maintenance dose: Start at 25µg/kg/min. May require escalation due to tachyphylaxis. Continuous EEG monitoring should be used with titration to burst suppression.
Lidocaine	Yes	Short period of efficacy, epileptogenic at high serum concentrations	Loading dose: 0.7–3mg/kg (typically 100mg total). May repeat if first bolus is ineffective.
Maintenance dose: Continuous infusion up to 0.06mg/kg/min. The maximum recommended dose is 300mg/hr (although higher dosages have been reported in past).
Paraldehyde	Yes (efficacy) Mixed reports (safety)	Not available in the United States; need to use dilute mixture to avoid dangerous adverse effects	IV or PO administration:
Loading dose: 100–200mg/kg (over 1hr if given IV).
Maintenance dose: Continuous infusion of 20mg/kg/hr or sequential bolus every 2–4hr of 40–80mg/kg.
Rectal administration:
Loading dose: 125–250mg/kg; then 50–100mg/kg every 2–4hr.
IM administration: Not recommended. Titrate paraldehyde to the lowest dose necessary to control seizures.
Magnesium	Yes: hypomagnesemia Yes: eclampsia No: other causes of SE	Useful in seizures due to eclampsia and hypomagnesemia, but not other causes	In hypomagnesemia: Replete to serum concentration 1.8–2.8mEq/L.
In eclampsia: 5gIV over 5–30min; then 1g/hr infusion. Intramuscular injection may be substituted with 10g bolus; then 5g every 4hr. Goal of 3.5–6.0mEq/L.
Note: None of the drugs listed in the table has been studied in a well-controlled clinical trial, and doses and regimens (if used) must be individualized for each patient.