Status Epilepticus Medication

Updated: Feb 13, 2018
  • Author: Julie L Roth, MD; Chief Editor: Stephen A Berman, MD, PhD, MBA  more...
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Medication

Medication Summary

Most patients with status epilepticus (SE) who are treated aggressively with a benzodiazepine, fosphenytoin, and/or phenobarbital experience complete cessation of their seizures. If SE does not stop, general anesthesia is indicated. The use of pentobarbital, thiopental, midazolam infusion, propofol, levetiracetam, topiramate, valproate, and inhaled anesthetic agents has been described for this purpose.

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Benzodiazepines

Class Summary

These are first-line agents for treating SE. They rapidly achieve therapeutic CNS concentrations after IV administration and act to potentiate action of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter in the CNS, and rapidly abrogate ongoing seizure activity. Their effect is temporary, which is a limitation; diazepam begins to redistribute out of CNS within minutes. Lorazepam, when available, is thought to be the most effective and has a longer seizure half-life than diazepam. Because the effect is time limited, loading of a traditional AED, such as phenytoin, is recommended soon after administration to help mitigate seizure recurrence.

Lorazepam (Ativan)

Lorazepam is preferred by most neurologists for treatment of SE because of its more prolonged CNS action. It is less fat-soluble than diazepam and therefore takes slightly longer (5-10 min) to stop seizures. It has a smaller volume of distribution than diazepam. Serum concentrations reach 50% of Cmax at 20 min. Lorazepam clears from the brain slower than diazepam but loses protective effect over 30-120 min.

It is important to monitor the patient's blood pressure after administering a dose. Adjust as necessary.

Diazepam (Diastat, Valium)

Diazepam is an extremely lipid-soluble agent that quickly enters the brain in first pass and often stops seizures in 1-2 min. It rapidly distributes to other stores of body fat. Its serum concentration decreases to 20% of maximum concentration (Cmax) 20 min after IV infusion. Individualize dosage and increase cautiously to avoid adverse effects.

Midazolam (Versed)

Midazolam is used as an alternative agent in termination of refractory SE. Because midazolam is water soluble rather than fat soluble, it takes approximately 3 times longer than diazepam to peak EEG effects. Thus, the clinician must wait 2-3 min to fully evaluate sedative effects before repeating a dose.

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Anticonvulsant Agents

Class Summary

These agents are used to terminate clinical and electrical seizure activity and to prevent seizure recurrence. Since the full antiepileptic effect of phenytoin, whether given as fosphenytoin or parenteral phenytoin, is not immediate, use of these agents usually follows administration of an IV benzodiazepine.

Phenytoin (Dilantin, Phenytek)

Phenytoin blocks sodium channels in the CNS. It may act in the motor cortex, where it may inhibit spread of seizure activity. The activity of brainstem centers responsible for tonic phase of grand mal seizures also may be inhibited. The dose should be individualized.

A mainstay in the treatment of SE, phenytoin must be administered slowly and therefore takes longer than benzodiazepines to enter the brain. Phenytoin has the advantage of being a long-term anticonvulsant and can be administered orally after acute illness.

Phenytoin is not water soluble, and must be solubilized in propylene glycol carrier with pH 12 to prepare IV form; therefore, it cannot be given at a rate faster than 50 mg/min without risk of significant hypotension and cardiac arrhythmias, as well as major risk of potential irritation at IV site and vascular compromise of the infused limb. Therefore, its use in SE should be avoided if possible.

Fosphenytoin (Cerebyx)

A phosphorylated phenytoin prodrug, fosphenytoin is highly water-soluble at physiologic pH and therefore is easier to administer than phenytoin. It is hydrolyzed rapidly and completely to phenytoin by endogenous phosphatases after a mean of 8 min and therefore can be administered more rapidly than standard phenytoin. Fosphenytoin also eliminates the risk of phlebitis and purple-glove syndrome seen with phenytoin, while achieving therapeutic CNS levels as quickly as phenytoin.

To avoid the need to perform molecular weight–based adjustments when converting between fosphenytoin and phenytoin sodium doses, the fosphenytoin dose is expressed as phenytoin equivalents (PE).

IM administration of fosphenytoin has been approved. However IV is still the route of choice for SE. Cardiac monitoring is required when this agent is administered IV but is not required for IM administration.

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Barbiturates

Class Summary

This class of anticonvulsant may be useful when SE fails to respond to phenytoin and benzodiazepines. It is the most commonly used third-line drug, but midazolam, propofol, and others are increasingly used in preference to phenobarbital, although no rigorous evidence supports the use of one third-line drug over another.

Phenobarbital

Phenobarbital works at CNS GABA receptors to potentiate CNS inhibition. It exhibits anticonvulsant activity in anesthetic doses. Phenobarbital is the best-studied barbiturate in treatment of SE.

In SE, achieving therapeutic levels as quickly as possible is important. IV dose may require approximately 15 min to attain peak levels in the brain. To terminate generalized convulsive SE, administer up to 15-20 mg/kg. If the patient has received a benzodiazepine, the potential for respiratory suppression significantly increases. Ventilation and intubation may be necessary. Hypotension may require treatment.

Phenobarbital is generally used after phenytoin or fosphenytoin fails. However, it can be used in lieu of phenytoin in certain circumstances.

If the IM route is chosen, administer this agent into a large muscle such as the gluteus maximus or vastus lateralis or other areas where risk of encountering nerve trunk or major artery is low. Permanent neurologic deficit may result from injection into or near peripheral nerves.

Restrict IV use to conditions in which other routes are not possible, either because patient is unconscious or because prompt action is required.

A trend is to recommend agents other than phenobarbital (propofol, midazolam, other barbiturates) for refractory SE.

Pentobarbital (Nembutal)

A short-acting barbiturate with sedative, hypnotic, and anticonvulsant properties, pentobarbital can produce mood alteration at all levels of CNS. Use only in refractory status when other agents have failed. Patients need intubation and respiratory support.

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Anesthetics

Class Summary

These agents stabilize the neuronal membrane so the neuron is less permeable to ions. This prevents the initiation and transmission of nerve impulses, thereby producing the local anesthetic effects. In SE, lidocaine is indicated for refractory cases only and its use is supported only by anecdotal reports. The consensus seems to be moving toward propofol or midazolam infusions for refractory status epilepticus.

Propofol (Diprivan)

A phenolic compound unrelated to other types of anticonvulsants, propofol has general anesthetic properties when administered IV. There are increasing anecdotal reports of its use in refractory status epilepticus. Intubation and ventilation are required. Hypotension may require treatment.

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