Ketamine Dosage

This dosage information may not include all the information needed to use Ketamine safely and effectively. See additional information for Ketamine.

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Usual Adult Dose for:

Additional dosage information:

Usual Adult Dose for Anesthesia

Parenteral:

Intravenous:

Induction: 1 to 4.5 mg/kg; alternatively, 1 to 2 mg/kg at a rate of 0.5 mg/kg/min may be used. (2 mg/kg dose provides 5 to 10 minutes of surgical anesthesia within 30 seconds following injection).

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.

Intramuscular:

Induction: 6.5 to 13 mg/kg; (9 to 13 mg/kg dose provides 12 to 25 minutes of surgical anesthesia within 3 to 4 minutes following injection).

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.

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Data not available

Dose Adjustments

As with other general anesthetic agents, the individual response to ketamine is somewhat varied depending on the dose, route of administration, and age of patient, so that the dosage recommendation cannot be absolutely fixed. The drug should be titrated against the patient's requirements.

Diazepam (2 to 5 mg over 60 seconds), administered in a separate syringe, may be used along with ketamine IV infusion for induction or maintenance of anesthesia. In most cases, 15 mg of IV diazepam or less will suffice.

Adult patients induced with ketamine augmented with IV diazepam may be maintained on ketamine given by slow microdrip infusion technique at a dose of 0.1 to 0.5 mg/min, augmented with diazepam 2 to 5 mg administered IV as needed. In many cases, 20 mg or less of IV diazepam total for combined induction and maintenance will suffice. However, slightly more diazepam may be required depending on the nature and duration of the operation, physical status of the patient, and other factors. The incidence of psychological manifestations during emergence, particularly dream-like observations and emergence delirium, may be reduced by this maintenance dosage program.

Precautions

Elevation of blood pressure begins shortly after injection of ketamine, reaches a maximum within a few minutes and usually returns to preanesthetic values within 15 minutes after injection. In the majority of cases, the systolic and diastolic blood pressure peaks from 10 to 50 % above preanesthetic levels shortly after induction of anesthesia, but the elevation can be higher or longer in individual cases.

Safety and effectiveness have not been established in pediatric patients under the age of 16.

Dialysis

Data not available

Other Comments

Ketamine should be administered slowly (over a period of 60 seconds). More rapid administration may result in respiratory depression and enhanced pressor response.

Because of rapid induction following the initial intravenous injection, the patient should be in a supported position during administration.

Since aspiration may occur with ketamine and since protective reflexes may also be diminished by supplementary anesthetics and muscle relaxants, the possibility of aspiration should be considered. Ketamine is recommended for use in the patient whose stomach is not empty when, in the judgment of the practitioner, the benefits of the drug outweigh the possible risks.

Atropine, scopolamine, or another drying agent should be given at an appropriate interval prior to induction.

Purposeless and tonic-clonic movements of extremities may occur during the course of anesthesia. These movements do not imply a light plane and are not indicative of the need for additional doses of ketamine.

Ketamine has a wide margin of safety; several instances of unintentional administration of overdoses of ketamine (up to 10 times that usually required) have been followed by prolonged but complete recovery.

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