Ketamine

Ketamine

Trade names	Ketalar
Clinical data
Drug class	Sedative hypnotic
Uses	Induction and maintenance of anesthesia, sedation, analgesia
Contraindications	<3 months old Situations where elevated blood pressure or myocardial oxygen demand would be dangerous Schizophrenia Use controversial with elevated ICP or IOP
Routes of administration	IV, IM, IN, PO, PR
Dosage	Induction of general anesthesia: 0.5-2 mg/kg IV
Dosage
Pharmacodynamics
Mechanism of action	NMDA-receptor antagonism
Adverse effects	Laryngospasm Hypersalivation Emesis Emergence reaction
Pharmacokinetics
Onset of action	IV: 15-30 seconds IM: 3-5 minutes
Duration of action	IV: 5-10 minutes IM: 12-30 minutes (residual 0.5-2 hours) PO: 1-6+ hours Context-sensitive half-time: 40-55 minutes after 8 hours of continuous infusion
Metabolism	Liver (CYP3A4, CYP2B6)
Elimination half-life	2.5-3 hours
Protein binding	23-47%
Physical and chemical data
Formula	C13H16ClNO
Molar mass	237.73 g/mol
Article quality
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Ketamine is a dissociative anesthetic used for the induction of anesthesia, procedural sedation, and as an analgesic adjunct.

Pharmacology

Pharmacokinetics

Metabolized by hepatic microsomal enzymes to norketamine via N-demethylation. Norketamine is then metabolized to hydroxynorketamine. Ultimately, hydroxynorketamine undergoes glucuronide conjugation and is excreted in the urine.

Norketamine has 33% of the potency of ketamine

The plasma disappearance of ketamine is traditionally described by a two-compartment model.

Elimination half-life: 2.5-2.8 hr

Clearance: 12-17 mL/kg/min

Vd at steady state: 3.1 L/kg

References

Kamp J, Olofsen E, Henthorn TK, van Velzen M, Niesters M, Dahan A; Ketamine Pharmacokinetic Study Group. Ketamine Pharmacokinetics. Anesthesiology. 2020 Dec 1;133(6):1192-1213. doi: 10.1097/ALN.0000000000003577. PMID: 32997732.

Miller, Ronald D. Miller's Anesthesia. 7th ed. Philadelphia, PA: Churchill Livingstone/Elsevier, 2010.