Ketamine is a noncompetitive N-methyl-D-aspartate receptor antagonist that blocks glutamate. It has a direct action on the cortex and limbic system. It produces a cataleptic-like state wherein the patient is withdrawn from the surrounding environment.

Ketamine is recommended for:

• As the sole anesthetic agent for diagnostic and surgical procedures that do not require skeletal muscle relaxation. Ketamine is best suited for short procedures and it can be used with additional doses, for longer procedures.
• For the induction of anesthesia prior to the administration of other general anesthetic agents.
• To supplement low-potency agents, such as nitrous oxide. 

Adult:

General Anesthesia-

• IV Induction: 1-4.5 mg/kg single dose
• IM Induction: 6.5-13mg
• IV Infusion: 1-2mg/kg at 0.5mg/kg/min

Maintenance: The maintenance dose should be adjusted according to the patient's anesthetic needs and whether an additional anesthetic is employed. Increments of one-half to the full induction dose may be repeated as needed for maintenance of anesthesia.

Rapid sequence Intubation, Induction - 2mg/kg IV

Pediatric:

General Anesthesia:

• IV Induction: 1-2 mg/kg IV; range: 4-13 mg/kg
• IM Induction: 5-10 mg/kg; range: 0.5-4.5 mg/kg
• Maintenance: 0.01-0.03 mg/kg/min continuous IV infusion

Maintenance: The maintenance dose should be adjusted according to the patient's anesthetic needs and whether an additional anesthetic is employed. Increments of one-half to the full induction dose may be repeated as needed for maintenance of anesthesia.

Administration

Rate of Administration: It is recommended that ketamine should be administered slowly (over a period of 60 seconds). More rapid administration may result in respiratory depression and enhanced pressor response.

The 100 mg/ml concentration of ketamine should not be injected intravenously without proper dilution. It is recommended the drug be diluted with an equal volume of either Sterile Water for Injection, USP, Normal Saline, or 5% Dextrose in Water.

CV disease including severe HTN; patients with increased intraocular or CSF pressure.

Emergence reactions (e.g. vivid dreams, hallucinations, confusion, irrational behaviour); increased muscle tone sometimes resembling seizures; temporary HTN and tachycardia, hypotension, bradycardia, arrhythmias, apnoea, laryngospasm, resp depression, diplopia, nystagmus, nausea, vomiting, lacrimation, hypersalivation, raised intraocular and CSF pressure, transient rash and pain at inj site, cystitis.

Overdose Effects

Symptoms: Resp depression.

Management: Employ supportive ventilation. Mechanical support of respiration is preferred to admin of analeptics.

Patient with cardiac decompensation, chronic alcoholic or acutely alcohol-intoxicated patients, pre-anaesth elevated CSF pressure, globe injuries, increased intraocular pressure (e.g. glaucoma), neurotic traits or psychiatric illness (e.g. schizophrenia, acute psychosis), acute intermittent porphyria, seizures, hyperthyroidism, pulmonary or upper resp infection, intracranial mass lesions, head injury, or hydrocephalus, hypovolaemia, dehydration, cardiac disease esp coronary artery disease (e.g. CHF, myocardial ischaemia, MI). Pregnancy and lactation.

Pregnancy & Lactation

Pregnancy: The safe use of ketamine in pregnancy has not been established, and such use is not recommended.

Lactation: Ketamine is likely to be excreted in breast milk and therefore breastfeeding should be discontinued when ketamine is in use.