Convulsive Status Epilepticus — Adult Doses
Reference doses, not an order. Select a drug for its contraindications and US label position — read them before giving any of these.
For clinicians. If you are not a healthcare professional and someone is seizing now, call emergency services and do not use this page for dosing. Single loading doses only, for convulsive status epilepticus in adults at least 40 kg — not maintenance dosing, not children, not non-convulsive status. Choose one drug per phase, not all of them, and verify against your local protocol before administration. Infusion times shown are floors set by each FDA label, not targets. Elderly, debilitated or critically ill patients: every label here requires a reduced dose or a slower rate, and this page calculates from weight only.
Showing the page default of 70 kg — this is not a measured weight. Enter the patient’s weight above.
Before any drug: airway, breathing, circulation and a neurological exam; oxygen, and consider intubation if respiratory assistance is needed; ECG monitoring; finger-stick glucose — if under 60 mg/dL give thiamine 100 mg IV then 50 mL D50W; IV access with electrolytes, hematology, toxicology screen and anticonvulsant levels. Time the seizure from its onset: the phase clocks below are minutes of seizure duration, not minutes since arrival.
Three equivalent first-line benzodiazepines, plus one fallback below them; pick by route and access, not by rank. AES directs an adequate single full dose rather than several small ones, and names insufficient dosing as one reason patients still receive inadequate treatment. Count what has already been given, including prehospital doses: one benzodiazepine, one repeat, then move to Phase 2 — do not restart the phase with a different benzodiazepine. The algorithm also lists rectal diazepam (0.2–0.5 mg/kg, max 20 mg, Level B) and intranasal or buccal midazolam (Level B) as alternatives, chiefly prehospital; this page does not dose them.
Only if none of the three above is available — AES grades phenobarbital Level A but places it below the benzodiazepines because it is slower to give.
Only if convulsions continue. One agent, one full single dose. The letter grades describe how much evidence exists for each drug on its own, not which is better — ESETT compared them head to head and found none most or least effective. Safety was also comparable and none of the differences reached significance: intubation within 60 minutes 20.0% (levetiracetam), 26.4% (fosphenytoin) and 16.8% (valproate); life-threatening hypotension 0.7%, 3.2% and 1.6%. If none is available, phenobarbital at the Phase 1 dose is the Level B fallback if it has not already been given.
Only if convulsions continue. The algorithm offers two choices: repeat the second-line therapy, or give anesthetic doses of thiopental, midazolam, pentobarbital or propofol — all with continuous EEG monitoring. Secure the airway and have vasopressors immediately available before starting anesthetic therapy. AES gives no dose here, so the figures below are from the 2024 Intensive Care Medicine review by Rossetti, Claassen and Gaspard. They are starting points, not targets: that review states the dose must be adjusted to reach EEG seizure control rather than a pre-specified number, and boluses are repeated as the rate rises. Midazolam and propofol are the two first choices, with comparable efficacy and safety; there is no evidence one is better. Continuous infusion calculators: propofol · midazolam · ketamine.
The number on each card is the bolus; the infusion rate that follows is in the note and is titrated on EEG. Seizure suppression, not burst suppression, is a reasonable EEG target, and expert opinion suggests holding sedation 24–48 h before weaning.
Cessation of convulsions is not cessation of seizures. Without EEG you cannot distinguish post-ictal or benzodiazepine sedation from continuing non-convulsive status epilepticus, and the goal of therapy is termination of both clinical and electrical seizure activity — so any patient who does not return to baseline after Phase 1 or Phase 2 needs an EEG, not just observation. The phase windows are ceilings, not waiting periods: AES states patients may move through the phases faster, or skip the second phase entirely, depending on etiology and severity. This page ends at the emergency load — maintenance dosing, drug levels and renal or hepatic adjustment are not covered, and about 1 in 9 patients re-seizes between 1 and 12 hours.
About This Status Epilepticus Drug Dose Calculator
This Status Epilepticus Drug Dose Calculator turns one patient weight into stepwise emergency doses for adult convulsive status epilepticus, laid out in the order and on the clock the American Epilepsy Society (AES) 2016 algorithm uses. The phase framework and Phase 1–2 regimens follow AES 2016; ESETT 2019 supplies the comparative second-line evidence, and a 2024 Intensive Care Medicine review supplies the Phase 3 starting doses, where AES names the drugs but gives no dose. It is built for the emergency physician, intensivist, neurologist or pharmacist at the bedside of a convulsing adult, where the arithmetic is trivial but doing it correctly under pressure, in the right order and within the right minutes, is not.
The scope is deliberately narrow: convulsive status epilepticus in an adult of at least 40 kg. It does not cover children, non-convulsive status epilepticus, or maintenance dosing after the emergency, including the renal and hepatic adjustments that apply to continuing therapy rather than to a single load. What it adds beyond the algorithm is the part that is easy to forget: each drug’s single-dose cap, and the minimum infusion time its own FDA label rate ceiling forces on the dose just calculated.
Treatment Algorithm
Figure 1. Adult convulsive status epilepticus treatment algorithm for adults ≥ 40 kg. The phase framework and Phase 1–2 regimens follow AES 2016, applied as an adults-only implementation: AES shows a 5 mg IM midazolam band for 13–40 kg, which was the pediatric dose in RAMPART, so 10 mg is used throughout this adult ≥ 40 kg scope. ESETT 2019 supports the second-line regimens and the 10-minute infusion; refractory-therapy starting doses are from Rossetti et al. 2024. The fosphenytoin 150 mg PE/min ceiling follows the Cerebyx prescribing information. Reference doses, not an order — verify local protocol.
Download this algorithm as a PDF — print or keep it on the unit.
How the Phases Work
Phase 1 (5–20 minutes): a benzodiazepine, and enough of it
Three options carry Level A evidence and the algorithm treats them as equivalent: intramuscular midazolam, intravenous lorazepam and intravenous diazepam. The choice is driven by access, not preference. IM midazolam needs no line, which is why RAMPART found seizures had stopped without rescue therapy at ED arrival in 73.4% of the IM midazolam group versus 63.4% of the IV lorazepam group. The difference was driven by how fast the drug reached the patient rather than by the drug itself: among subjects whose seizures ceased before arrival, median time to active treatment was 1.2 minutes for IM versus 4.8 for IV, while once given, IV lorazepam stopped convulsions in a median 1.6 minutes versus 3.3. Intubation was equally common (14.1% versus 14.4%). Where a line is already in, the two are equivalent. If none of the three is available, phenobarbital is one alternative at this stage and the only Level A one, though AES places it below the benzodiazepines because it is slower to give.
Phase 2 (20–40 minutes): one full second-line dose
The AES grades this phase Level U: there is no evidence-based preferred agent. ESETT, which randomized levetiracetam, fosphenytoin and valproate in benzodiazepine-refractory status, is the reason. Cessation with improvement in the level of consciousness occurred in 47%, 45% and 46% of patients, and the trial was stopped for futility because no drug was likely to prove most or least effective. Safety was comparable and no difference was significant: intubation within 60 minutes 20.0%, 26.4% and 16.8%, life-threatening hypotension 0.7%, 3.2% and 1.6%. The practical consequence is that the fastest agent to reach the patient is usually the best one, provided no contraindication applies.
Phase 3 (40–60 minutes): repeat, or anesthesia with cEEG
Beyond one full second-line dose the evidence runs out. The algorithm allows either a repeat of second-line therapy or anesthetic doses of thiopental, midazolam, pentobarbital or propofol, and requires continuous EEG for the anesthetic route. This calculator deliberately produces no number here: an anesthetic infusion is titrated to a burst-suppression or seizure-suppression target on EEG, not calculated from body weight in advance.
Levetiracetam (Keppra) Loading Dose
The status epilepticus loading dose is 60 mg/kg as a single dose, capped at 4,500 mg, infused over 10 minutes. A 70 kg adult receives 4,200 mg; from 75 kg upwards every adult receives the same 4,500 mg. None of that is labeled: the US injection is approved only as adjunct therapy when oral dosing is not feasible, at a maximum recommended daily dose of 3,000 mg. The loading dose is off-label on indication, dose and infusion time at once, and comes from AES 2016 and ESETT rather than the package insert.
Where the Guideline Dose Sits Outside the US Label
Four of the seven regimens are standard of care and are not labeled uses, which matters when a pharmacist queries the order: levetiracetam (off-label on indication, dose and infusion time), valproate (indication and speed), intramuscular midazolam (no status epilepticus indication at all), and phenobarbital, whose label gives a mg/kg status epilepticus dose only for children. Fosphenytoin, lorazepam and diazepam carry status epilepticus indications, though fosphenytoin’s 1,500 mg PE cap falls below its labeled 15–20 mg PE/kg range above 100 kg. Each card states its own drug’s label position in full. None of this argues against the guideline — it is why the page prints each label’s own ceiling beside the dose.
How Current These Sources Are
The algorithm’s backbone is the AES 2016 guideline, which is ten years old but has not been superseded: no newer evidence-based treatment guideline for adult convulsive status epilepticus has been published, and the 2026 Neurocritical Care Society guideline covers neuroprognostication rather than dosing. The largest randomized trial of second-line therapy is still ESETT (2019). Where the guideline is silent — the Phase 3 anesthetics — the doses come from the 2024 Intensive Care Medicine review, the most recent authoritative source with a dosing table. RAMPART (2012) and the Treiman VA trial (1998) are cited for their own results, which no later trial has restated. Every FDA label used here was retrieved in its current version, dated between February 2025 and August 2026, and all six cited papers were checked for errata, corrections and retractions: none has any.
Limitations
Doses are single doses on total body weight, and the algorithm’s repeat allowances are stated on each card rather than folded into the headline number. The page takes weight only: it cannot apply the dose reductions every one of these labels requires in the elderly, the debilitated and the critically ill, and it does not cover pregnancy, where phenobarbital is Category D and valproate carries a fetal-risk boxed warning. Minimum infusion times are arithmetic from each label’s maximum rate: they are floors, not recommendations. Contraindications are summarized, not exhaustive. This tool does not replace clinical judgment, local protocol, or the pharmacist.
Frequently Asked Questions (FAQ)
1. Why is lorazepam capped at 4 mg in status epilepticus?
The AES algorithm doses lorazepam at 0.1 mg/kg per dose with a maximum of 4 mg, and 0.1 mg/kg reaches 4 mg at 40 kg. Every adult therefore receives the same 4 mg. The FDA label agrees, stating a flat 4 mg for patients 18 years and older at no more than 2 mg per minute. The cap is per dose, not per episode: one repeat is part of the algorithm.
2. Is this the same as a Keppra loading dose for seizures?
Yes. Levetiracetam, sold as Keppra, is one of the three second line options, loaded at 60 mg/kg to a maximum of 4,500 mg as a single dose. This is not a labeled use: the US injection label covers levetiracetam only as adjunct therapy when oral dosing is not feasible, with a maximum recommended daily dose of 3,000 mg. The loading dose comes from ESETT and the guideline, not the package insert.
3. Which second line drug for status epilepticus is best?
None is established as better. ESETT randomized levetiracetam, fosphenytoin and valproate in benzodiazepine refractory status and found seizure cessation with improvement in the level of consciousness in 47, 45 and 46 percent. The trial was stopped for futility because no drug was likely to prove most or least effective. AES grades the choice Level U. Choose on what is stocked and drawn up fastest, on liver disease or pregnancy for valproate, and on cardiac risk for fosphenytoin.
4. When does status epilepticus need anesthetic doses and cEEG?
The third phase begins at 40 to 60 minutes, when seizures continue after an adequate benzodiazepine and one full second line agent. AES lists two Level U options: repeat the second line therapy, or give anesthetic doses of thiopental, midazolam, pentobarbital or propofol, all with continuous EEG monitoring. Without EEG you cannot distinguish sedation from continuing non convulsive status epilepticus, and the goal of therapy is termination of both clinical and electrical seizure activity.
5. Why does this status epilepticus calculator exclude children?
Pediatric dosing diverges exactly where this tool starts. Intramuscular midazolam is 10 mg above 40 kg but 5 mg in the 13 to 40 kg band, and the fosphenytoin label sets a weight based rate ceiling of 2 mg PE/kg/min for children instead of the adult flat ceiling. Applying adult rules to a small child would overdose the benzodiazepine, so the weight floor here is 40 kg.
Related Calculators
📖 Sources:
- Glauser T, Shinnar S, Gloss D, et al. (2016). Evidence-Based Guideline: Treatment of Convulsive Status Epilepticus in Children and Adults. Epilepsy Curr. PMID: 26900382.
- Kapur J, Elm J, Chamberlain JM, et al. (2019). Randomized Trial of Three Anticonvulsant Medications for Status Epilepticus. N Engl J Med. PMID: 31774955.
- Silbergleit R, Durkalski V, Lowenstein D, et al. (2012). Intramuscular versus intravenous therapy for prehospital status epilepticus. N Engl J Med. PMID: 22335736.
- Treiman DM, Meyers PD, Walton NY, et al. (1998). A comparison of four treatments for generalized convulsive status epilepticus. N Engl J Med. PMID: 9738086.
- Rossetti AO, Claassen J, Gaspard N. (2024). Status epilepticus in the ICU. Intensive Care Med. PMID: 38117319. — source of the Phase 3 anesthetic doses, which the AES algorithm does not specify.
- Cerebyx (fosphenytoin sodium) injection PI, Pfizer (label version current as of Aug 2025). DailyMed setid d4c36fad-0ba2-4cd4-9c5e-dcf843f38a5a.
- Lorazepam Injection PI (Hospira, Jul 2026) · Diazepam Injection PI (Baxter, Aug 2026) · Phenobarbital Sodium Injection PI (Nexus, Dec 2025). DailyMed.
- Levetiracetam in Sodium Chloride Injection PI (Fresenius Kabi, Jun 2026) · Valproate Sodium Injection PI (Fresenius Kabi, Feb 2025) · Midazolam Injection PI (Hospira, Aug 2026). DailyMed.
- Diprivan (propofol) injectable emulsion PI (Fresenius Kabi, Sep 2025) · Ketalar (ketamine) injection PI (Par, Mar 2026) · Pentobarbital Sodium Injection PI (Hikma, Mar 2026). DailyMed — Phase 3 contraindications and the propofol infusion syndrome warning.
📝 How to cite this page:
DosePilot Medical Team. Status Epilepticus Drug Dose Calculator. DosePilot. Published August 17, 2026. Last medically reviewed August 2026. https://dosepilot.com/calc/status-epilepticus-dose-calculator/
⚠️ Disclaimer:
This Status Epilepticus Drug Dose Calculator is intended to assist, not replace, experienced medical personnel. All treatment decisions must be made by a qualified healthcare professional considering the individual patient’s full clinical context. Status epilepticus is a time-critical emergency requiring airway, breathing and circulation management alongside drug therapy.
