By Dr. Abdolghader Pakniyat, peer-reviewed by Dr. S. Berdouk.

Scope: Adult generalized convulsive status epilepticus, with discussion of refractory and nonconvulsive status. Doses and timings are educational examples, not an adopted local protocol. Neonatal and pediatric dosing require separate pathways. Count rescue medication already given before arrival.

Status Epilepticus — Shift Cheat Sheet (ED)

Mantra: Right drug. Right dose. Right now.
Timing: Treat an ongoing generalized convulsive seizure at 5 minutes, or immediately on arrival if that duration has already elapsed or is unknown. Escalate promptly after adequate benzodiazepine treatment fails; do not wait for a displayed time window. Record onset-to-treatment and arrival-to-treatment separately. Arrange cEEG as soon as feasible when indicated.

Stabilize while the first drug is given

Call for help. Position and suction the airway, give oxygen for hypoxemia, and assist ventilation if breathing is inadequate. Monitor ECG, blood pressure, oxygen saturation and temperature. Check bedside glucose and treat hypoglycemia immediately. Obtain IV access; use IO access when necessary. Access attempts, blood sampling and CT must not postpone seizure treatment. AES guideline, 2016.

First-line treatment: an adequate benzodiazepine

These are route-specific AES regimens. Review prehospital doses before giving more; do not automatically repeat 10 mg IM midazolam or substitute that fixed dose intravenously. Prepare second-line therapy during the initial response assessment. AES guideline, 2016.

Give IV lorazepam slowly, no faster than 2 mg/min, with ventilation equipment and cardiorespiratory monitoring. Two 4-mg doses total 8 mg; 8 mg is not the initial-dose ceiling. Follow the local emergency protocol for reassessment and repeat timing. Lorazepam prescribing information.

Persistent convulsions: load a second-line drug

The following are the ESETT trial regimens, each infused over 10 minutes. Select one promptly when adequate benzodiazepine treatment fails; check contraindications and the local preparation protocol. ESETT randomized trial, 2019.

PE means phenytoin equivalents. Fosphenytoin requires ECG, blood-pressure and respiratory monitoring during and after infusion; do not exceed 150 mg PE/min in adults. Avoid it with relevant conduction disease, including second- or third-degree AV block. IM administration is unsuitable for urgent control. Fosphenytoin prescribing information.

If treatment fails, escalate immediately

Ongoing seizures despite an adequate benzodiazepine and an appropriate second-line load are refractory status epilepticus. Call neurology and critical care, secure the airway when required, and arrange cEEG. Persistent convulsive RSE generally needs a monitored anesthetic infusion, such as midazolam or propofol, with a maintenance antiseizure plan. Do not wait for a 30- or 60-minute mark. Neurocritical Care Society guideline, 2012.

If convulsions stop but consciousness does not improve, consider nonconvulsive seizures alongside postictal, sedative, metabolic and structural causes. ACNS advises considering cEEG when alertness is not clearly improving within 10 minutes, or remains impaired beyond 30 minutes after clinical seizure cessation. Start as soon as feasible. ACNS EEG consensus, 2015.

Deep Dive

The clinical snapshot

A 79-year-old with atrial fibrillation arrives convulsing; EMS gave 5 mg IM midazolam en route. At minute 9, he remains in tonic–clonic activity; glucose 108 mg/dL, BP 168/92, SpO₂ 89% on NRB, no IV access.

Treat hypoxemia and ongoing convulsions together. Confirm when EMS gave midazolam and count that dose when planning further rescue treatment. Obtain IV/IO access and prepare the second-line load; arrival in the ED does not restart the seizure clock. RAMPART randomized trial, 2012.

Why early treatment matters

For generalized tonic–clonic SE, ILAE uses t1 = 5 minutes as the treatment threshold and t2 ≈30 minutes as the point beyond which lasting injury may occur. Recurrent convulsions without recovery also warrant urgent treatment. Thirty minutes is neither a safe waiting period nor an exact injury boundary for every patient. Other forms of SE have different thresholds. ILAE definition, 2015.

Prolonged firing can weaken inhibition as synaptic GABA-A receptors move away from the cell surface. Experimental receptor-trafficking studies help explain declining benzodiazepine responsiveness. They do not establish a universal human switch at minute 5 or 30, or justify skipping initial benzodiazepines in a late presentation. Naylor receptor-trafficking experiment, 2005.

Excitatory receptor changes also help sustain seizure activity. This makes treatments acting through other mechanisms biologically plausible. It does not prove that a fixed early drug combination improves patient outcomes. Escalation should follow treatment response, supported clinical evidence and EEG findings, rather than an assumed receptor timetable. NMDA-receptor trafficking experiment.

What the trials support

When IV access is absent, a practical route matters. RAMPART found IM midazolam at least as effective as IV lorazepam for prehospital seizure cessation; IV access delayed treatment. This supports giving an available, appropriate non-IV rescue treatment promptly rather than repeatedly trying to cannulate first. RAMPART randomized trial, 2012.

Benzodiazepines can depress breathing, so prepare to ventilate. However, ongoing status itself causes respiratory compromise: in the placebo-controlled prehospital trial, respiratory or circulatory complications were numerically more frequent with placebo. Fear of sedation should not become a reason for ineffective dosing. Prehospital benzodiazepine trial, 2001.

ESETT studied benzodiazepine-refractory convulsive SE in patients aged at least 2 years. Its clinical endpoint, 60 minutes after infusion began, combined seizure cessation, improved responsiveness and no additional antiseizure treatment; roughly half responded to each drug. No clear winner emerged. This was not proof of universal equivalence, and it did not establish EEG-confirmed seizure freedom. ESETT randomized trial, 2019.

The age-group analysis likewise detected no efficacy difference, but the older-adult subgroup was small. These results do not create a neonatal pathway or settle drug choice in pregnancy, severe organ disease or toxin-induced seizures. Match treatment to the individual patient. ESETT age-group analysis, 2020.

Choose by the risks that matter

Levetiracetam: renal function matters for subsequent maintenance dosing. Separate the emergency loading decision from the ongoing dose and interval; involve pharmacy for renal impairment or dialysis. Levetiracetam prescribing information.

Valproate: avoid with hepatic disease or significant hepatic dysfunction, known POLG-related mitochondrial disease or urea-cycle disorders. Pregnancy requires urgent specialist selection of alternatives where suitable because of fetal risks; ongoing status still requires immediate treatment. Thrombocytopenia and hyperammonemic encephalopathy also matter. Valproate prescribing information.

Existing antiseizure therapy: maintenance use alone does not prohibit emergency loading. Check recent doses, available drug levels, interactions and toxicity. Continue an appropriate maintenance plan; do not omit needed treatment while waiting for levels. UK adult status guidance, 2025.

Route matters: IM diazepam has delayed, variable effects and is a poor routine choice for convulsive SE. This should not be generalized to licensed diazepam nasal spray, which is a seizure-cluster rescue product with its own age/weight dosing and repeat instructions. A cluster plan and a monitored ED status pathway are different clinical contexts. Japanese epilepsy guideline, 2018. Diazepam nasal-product label.

Refractory care: control seizures without adding harm

Super-refractory SE persists or recurs at least 24 hours after anesthetic treatment begins, including during its withdrawal. NCSE without coma needs EEG-informed specialist decisions; the convulsive RSE pathway should not trigger automatic anesthesia for every nonconvulsive presentation. UK adult status guidance, 2025.

Continuous anesthetic treatment needs ICU support, cEEG and reassessment of perfusion, ventilation and the cause. Have vasopressors available. Plan for hypotension and cumulative respiratory depression, especially with barbiturates plus benzodiazepines. Infusion dose, EEG target and weaning are specialist decisions; 24–48 hours of electrographic control before tapering is a consensus approach, not a universal guarantee. Neurocritical Care Society guideline, 2012.

Propofol: monitor for infusion syndrome, including new metabolic acidosis, rhabdomyolysis, hyperkalemia and cardiac dysfunction. Risk rises with prolonged high-dose exposure but is not confined to one dose/time cutoff. Propofol prescribing information.

Lacosamide: an additional drug may be selected by the specialist team, but review ECG and interacting medicines because PR prolongation and serious arrhythmias can occur. Lacosamide prescribing information.

Ketamine: observational SRSE cohorts report reductions in seizure burden, often with other anesthetics already running. They do not establish the best dose, timing, comparative benefit or outcome. Use an institutional neurocritical-care regimen with cEEG rather than a universal high-dose range. Hemodynamic stability cannot be assumed. Ketamine SRSE cohort, 2020.

Ketamine labeling warns against coadministration with theophylline or aminophylline because seizure threshold may fall. Hypotension, hypertension and arrhythmias are possible. Sedative combinations can cause profound respiratory depression; monitor cardiac and respiratory function. Ketamine prescribing warnings.

Neuromuscular blockade stops movement without treating cortical seizures. Do not use routine prolonged paralysis as a seizure endpoint. If paralysis is needed for airway management or another compelling indication, continue antiseizure/sedative treatment and obtain urgent EEG; lifesaving intubation must not wait for EEG availability. ACNS EEG consensus, 2015.

Find and treat the cause in parallel

Review epilepsy history, missed medicines, withdrawal, toxins, infection and acute structural disease. Check electrolytes, renal/liver function, pregnancy testing when relevant and targeted drug levels; investigate persistent lactate elevation, hyperthermia or rhabdomyolysis. Obtain urgent brain imaging after stabilization when the cause is unclear or structural disease is suspected. For possible CNS infection, assess for lumbar puncture and contraindications; do not postpone indicated empiric treatment while arranging tests. UK adult status guidance, 2025.

Drug-induced seizures: involve the poison center early. Benzodiazepines are first-line; phenytoin/fosphenytoin is generally unsuitable. Do not assume levetiracetam, valproate or ketamine is preferred for every tricyclic-antidepressant, cocaine or theophylline exposure. Treat toxin-specific threats as well as the seizure. Utah Poison Control seizure guidance.

Suspected isoniazid poisoning: give pyridoxine with benzodiazepines and call the poison center. The Quebec adult regimen starts with 5 g by slow IV infusion over 10 minutes while convulsing; if seizures stop sooner, give the remainder over 4 hours. The dose may be repeated once for recurrence under toxicology guidance. Confirm preparation and any adjustment for a known ingestion with the poison center. Quebec Poison Control pyridoxine guide.

Eclampsia: call obstetrics and critical care. NICE uses magnesium sulfate 4 g IV over 5–15 minutes, then 1 g/hour for 24 hours after the last fit. Recurrent fits require another 2–4 g IV over 5–15 minutes. Monitor respiration, reflexes, urine output and magnesium; renal impairment needs dose adjustment. Stop for significant toxicity and have injectable calcium available under the obstetric protocol. Assess other possible causes of seizures in pregnancy. NICE eclampsia guidance. Magnesium sulfate product information.

Metabolic triggers: correct hypoglycemia and dangerous sodium, calcium or magnesium abnormalities promptly with the relevant emergency protocol. Antiseizure drugs alone cannot correct the underlying disturbance. Neurocritical Care Society guideline, 2012.

NORSE/FIRES

New-onset refractory SE without an immediately clear cause needs tertiary neurocritical-care investigation, including infectious and autoimmune causes. NORSE/FIRES consensus supports first-line immunotherapy within 72 hours, often earlier after common infections are excluded, and second-line treatment within 7 days when appropriate. These are specialist, low-certainty recommendations; treatment choice depends on the suspected cause, and plasma exchange is not a universal default. International NORSE/FIRES consensus, 2022.

Reassessment and handover

Keep onset time, arrival time, every dose/route, response, respiratory support and escalation decisions together. Agree a maintenance plan, EEG access and admission or transfer. As a local quality-improvement measure, audit treatment delays and adequate dosing separately; a service target must never become permission to wait. NICE epilepsy guidance.

Recovery depends on the cause, duration and clinical course. In older adults, do not assume persistent reduced consciousness is simply postictal; reassess and obtain EEG when indicated. Early treatment cannot promise recovery. ILAE definition, 2015. ACNS EEG consensus, 2015.