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Ketamine RSI dose for adults: verify the 2 mg/kg estimate and when sources go lower

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The ketamine RSI dose StatPearls gives is 2 mg/kg IV, the same figure the current FDA label gives as its average induction dose, inside a labeled range of 1 to 4.5 mg/kg. Rapid Vent Calculator multiplies that scalar by the entered actual body weight. For older adults the label describes starting at the low end of its range; evidence on lowering the dose in shock is mixed. This page covers adult patients only; see the full adult RSI medications table for where ketamine sits among the other five drugs.

Ketamine RSI dose: what each source states
SourceWhat it statesSetting and weight basis
FDA ketamine labelIV initial dose 1 to 4.5 mg/kg, administered over 60 seconds; average 2 mg/kg for 5 to 10 minutes of surgical anesthesia; for an elderly patient, cautious dose selection, usually starting at the low end of the rangeSurgical anesthesia; mg/kg with no weight descriptor
StatPearls NBK4592762 mg/kg IV for intubationEmergency intubation; no descriptor
Erstad and Barletta, 2020Ideal or adjusted body weight suggested in obesity, particularly BMI 40 or aboveCritically ill obese adults; no dose stated
Miller et al., 2016Hypotension after ketamine induction in 26% of high shock-index patients vs 2% of low shock-index patientsOut-of-hospital RSI; dose not stated in the abstract
Driver et al., 2023No association between weight-based ketamine dose and post-intubation hypotension; median dose 1.33 mg/kgED registry, patients aged 14 and older
Krebs et al., 2021Doses above 2 mg/kg associated with more adverse events than doses of 2 mg/kg or lessMultisite retrospective prehospital RSI, adults

Figures are what each source reports, not a dosing instruction. The label’s figures come from surgical anesthesia. The Driver 2023 registry included patients aged 14 and older, stated here because it is needed to show both sides of the shock question. Your protocol sets the dose actually given.

Where the 2 mg/kg ketamine RSI dose comes from

2 mg/kg is the average intravenous dose on the FDA’s current ketamine label, and StatPearls prints the same figure for intubation. The label states the initial dose “may range from 1 mg/kg to 4.5 mg/kg,” with “the average amount required to produce 5 to 10 minutes of surgical anesthesia within 30 seconds following injection” at 2 mg/kg, a figure from surgical anesthesia, not emergency intubation. The label adds that dosing “must be individualized and titrated to the desired clinical effect,” describes administering it over 60 seconds, and states that a rapid administration rate may cause respiratory depression. That labeled duration, 5 to 10 minutes, matters again once the paralytic outlasts it.

What does 2 mg/kg of ketamine come to for an 80 kg adult?

160 mg, as an arithmetic estimate. 80 kg x 2 mg/kg = 160 mg. A weight given in pounds converts first: the calculator divides by 2.2, so 176 lb becomes 80 kg before the multiplication runs. The medications card shows the result rounded to a whole milligram, scalar and number side by side. Converting pounds to kilograms for drug doses gets its own page.

Ketamine dosing weight: actual body weight, and where obesity splits the sources

The FDA label expresses the ketamine dose per kilogram and names no weight descriptor. Rapid Vent Calculator multiplies 2 mg/kg by the actual body weight entered, and its reference sheet adds: “Some agents may be dosed by ideal or adjusted body weight in obese patients depending on local protocol and reference used.” A 2020 review of drug dosing in critically ill obese adults suggests ideal or adjusted body weight for ketamine in obesity, particularly at a BMI of 40 or above, reasoning that its clearance tracks lean body mass rather than fat (Erstad and Barletta, 2020). The same review calls actual weight appealing for loading doses. Both practices are in use, and this page ranks neither. Actual vs ideal body weight across all six RSI drugs lays out the full comparison.

When sources describe a lower ketamine dose: older adults and shock

Two situations recur in the published record: older adults and shock, and on shock the evidence itself is mixed. Each position below carries its own citation; this page adjudicates none of them.

For an elderly patient, the FDA label says dose selection “should be cautious, usually starting at the low end of the dosing range,” reasoning that older patients more often have reduced hepatic, renal, or cardiac function.

Miller and colleagues (2016) followed out-of-hospital ketamine inductions grouped by shock index. High shock-index patients became hypotensive more often, 26%, than low shock-index patients, 2%, with a blunted rather than sustained blood pressure response after induction.

Two larger studies complicate that finding. Driver and colleagues (2023), in a registry of patients aged 14 and older intubated with etomidate or ketamine, found no association between the weight-based ketamine dose and post-intubation hypotension (median dose 1.33 mg/kg). De Mucha and Thomas (2025), in a meta-analysis of emergency RSI studies that excluded pediatric-only studies, found post-induction hypotension with ketamine no different from comparator agents across 27 pooled studies, with doses ranging from 0.5 mg/kg to above 2 mg/kg.

Two narrative reviews describe reducing the dose as their own position. A 2020 emergency-medicine review describes reducing the induction dose of any agent by half or more in unstable patients (Lentz et al., 2020). A 2019 review of airway management with ketamine, which also discusses pediatric patients, describes reducing the ketamine induction dose “by at least half” in patients with high perfusion deficits (Merelman et al., 2019).

This page reports each position with its citation. Which figure, if any, applies to a given patient is set by the crew’s protocol and medical direction, and no reduced dose prints here as an instruction.

Why can ketamine drop blood pressure in shock?

The FDA label points to catecholamines. It states that ketamine’s cardiovascular effects “are indirect and believed to be mediated by inhibition of both central and peripheral catecholamine reuptake,” and lists cardiac decompensation “in patients with suspected catecholamine depletion.” A 2025 meta-analysis adds that ketamine’s direct myocardial depression “might outweigh sympathomimetic-driven increases in systemic vascular resistance in critically ill patients with depleted catecholamine reserves,” though it found its own subgroup results did not support that idea (De Mucha and Thomas, 2025).

Is a ketamine dose above 2 mg/kg linked to more adverse events?

In one retrospective study, yes. Krebs and colleagues (2021), in a multisite retrospective prehospital study of adults, compared 80 patients dosed at 2 mg/kg or less against 50 dosed above 2 mg/kg. The higher-dose group had greater odds of hypotension, laryngospasm, bradycardia, repeat medications, oxygen desaturation, multiple intubation attempts, and a failed airway, though that group also had more trauma patients, was younger, and started with higher blood pressure, differences the abstract reports. The label’s range still extends to 4.5 mg/kg for surgical anesthesia, and the authors call for more study of lower doses in shock.

Published ketamine RSI dose figures on a mg/kg lineA number line from 0 to 5 mg/kg. The FDA label range runs from 1 to 4.5 mg/kg. A point at 2 mg/kg marks the FDA average and StatPearls figure. A point at 1.33 mg/kg marks the median dose from Driver 2023’s ED registry of patients aged 14 and older. A bracket from 0.5 to above 2 mg/kg marks the range of doses across studies in De Mucha 2025’s meta-analysis of emergency RSI studies, which excluded pediatric-only studies. An open marker just past 2 mg/kg marks Krebs 2021’s finding, in adult prehospital RSI, of higher adverse-event odds above that dose.FDA label range: 1 to 4.5 mg/kg2 mg/kg: FDA average, StatPearls1.33 mg/kg: median, ED registry (Driver 2023)Doses across studies, 0.5 to above 2 mg/kg (De Mucha 2025)Above 2 mg/kg: higher adverse-event odds (Krebs 2021)012345 mg/kg
Each mark is what one source reports, in its own population: the FDA figures come from surgical anesthesia; Driver 2023 is a registry of patients aged 14 and older; De Mucha 2025 is a meta-analysis of emergency RSI studies that excluded pediatric-only studies; Krebs 2021 studied adults in prehospital RSI. None is a dosing instruction; the protocol sets the dose.

Verify the calculated ketamine RSI dose against the patient

Rapid Vent Calculator’s medications card lists ketamine first under “INDUCTION AGENTS,” the 2 mg/kg scalar in small text beside the calculated milligram result, computed from whatever actual weight was entered. The footer beneath the doses reads: “Displayed doses are calculated from entered actual body weight.” The arithmetic does not know the patient’s age, blood pressure, shock index, or build, and it does not lower the number for any of them, multiplying only the weight it is given. Whether 2 mg/kg fits the patient in front of the crew, or a lower figure above applies instead, is the protocol’s call, not the screen’s.

After the ketamine: sedation and the first vent settings

Ketamine’s labeled surgical-anesthesia duration is 5 to 10 minutes. Rocuronium, a paralytic that can follow it, runs far longer per its FDA label: 31 minutes at 0.6 mg/kg and 67 minutes at 1.2 mg/kg. A patient can be paralyzed after the ketamine wears off, and the ED-AWARENESS study found possible or definite awareness in 2.6% of ventilated ED adults; what happens when an induction agent wears off before the paralytic is its own page. Sedation after the tube is scored on a scale rather than eyeballed (NASEMSO v3.0), the RASS scale for sedation after the tube, with no band or target printed here. From there the weight switches: tidal volume runs on ideal body weight, not the actual weight the ketamine dose used (StatPearls NBK537072). The initial ventilator settings that follow RSI pick up from there; which induction agent to reach for first, ketamine vs etomidate for RSI, is its own question.

Sources

  1. US Food and Drug Administration. Ketamine Hydrochloride Injection, USP (CIII) prescribing information (Civica, Inc.). DailyMed; revised June 2026. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=58c86d9b-8694-4bd8-8254-f19ee3ad60b0
  2. Hendrix JM, Regunath H. Intubation Endotracheal Tube Medications. In: StatPearls. StatPearls Publishing; updated January 19, 2025. NCBI Bookshelf NBK459276. https://www.ncbi.nlm.nih.gov/books/NBK459276/
  3. Miller M, Kruit N, Heldreich C, et al. Hemodynamic response after rapid sequence induction with ketamine in out-of-hospital patients at risk of shock as defined by the shock index. Annals of Emergency Medicine. 2016;68(2):181-188.e2. https://pubmed.ncbi.nlm.nih.gov/27130803/
  4. Driver BE, Trent SA, Prekker ME, Reardon RF, Brown CA. Sedative dose for rapid sequence intubation and postintubation hypotension: is there an association? Annals of Emergency Medicine. 2023;82(4):417-424. https://pubmed.ncbi.nlm.nih.gov/37389494/
  5. Krebs W, Werman H, Jackson J, et al. Prehospital ketamine use for rapid sequence intubation: are higher doses associated with adverse events? Air Medical Journal. 2021;40(1):36-40. https://pubmed.ncbi.nlm.nih.gov/33455623/
  6. de Mucha PV, Thomas S. Incidence of post-induction hypotension following emergency rapid sequence induction with ketamine: a systematic review and meta-analysis. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine. 2025;33:71. https://pmc.ncbi.nlm.nih.gov/articles/PMC12044812/
  7. Erstad BL, Barletta JF. Drug dosing in the critically ill obese patient: a focus on sedation, analgesia, and delirium. Critical Care. 2020;24:315. https://pmc.ncbi.nlm.nih.gov/articles/PMC7282067/
  8. Lentz S, Grossman A, Koyfman A, Long B. High-risk airway management in the emergency department. Part I: diseases and approaches. Journal of Emergency Medicine. 2020;59(1):84-95. https://pmc.ncbi.nlm.nih.gov/articles/PMC7214321/
  9. Merelman AH, Perlmutter MC, Strayer RJ. Alternatives to rapid sequence intubation: contemporary airway management with ketamine. Western Journal of Emergency Medicine. 2019;20(3):466-471. https://pmc.ncbi.nlm.nih.gov/articles/PMC6526883/
  10. US Food and Drug Administration. Rocuronium bromide injection prescribing information (Hospira). DailyMed, revised June 2025. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=309aeb1b-8022-4df7-8194-ae6529e3395c
  11. Pappal RD, Roberts BW, Mohr NM, et al. The ED-AWARENESS Study: A Prospective, Observational Cohort Study of Awareness With Paralysis in Mechanically Ventilated Patients Admitted From the Emergency Department. Annals of Emergency Medicine. 2021;77(5):532-544. https://pubmed.ncbi.nlm.nih.gov/33485698/
  12. NASEMSO Medical Directors Council. National Model EMS Clinical Guidelines, Version 3.0. National Association of State EMS Officials; March 2022.
  13. Kuhl EA, Perera TB. Prehospital Mechanical Ventilation. In: StatPearls. StatPearls Publishing; updated March 8, 2024. NCBI Bookshelf NBK537072. https://www.ncbi.nlm.nih.gov/books/NBK537072/