2 DOSAGE AND ADMINISTRATION
2.1 Important Dosage and Administration Information
Ketamine Hydrochloride should be administered by or under the direction of physicians experienced in the administration of general anesthetics, maintenance of a patent airway, and oxygenation and ventilation. Continuously monitor vital signs in patients receiving Ketamine Hydrochloride.
Emergency airway equipment must be immediately available.
Do not administer the 100 mg/mL concentration of Ketamine Hydrochloride intravenously without proper dilution [see Dosage and Administration (2.3)]. Must be used immediately after dilution.
While some degree of airway protection may be afforded due to active laryngeal-pharyngeal reflexes, vomiting and aspiration may occur with ketamine. Ketamine Hydrochloride is not recommended for use in patients who have not followed nil per os guidelines.
Due to the potential for salivation during Ketamine Hydrochloride administration, administer an antisialagogue prior to induction of anesthesia.
In individuals with a history of chronic ketamine use for off-label indications, there have been case reports of genitourinary pain that may be related to the ketamine treatment, not the underlying condition [see Adverse Reactions (6)]. Consider cessation of ketamine if genitourinary pain continues in the setting of other genitourinary symptoms.
2.2 Recommended Dosage and Administration
The Ketamine Hydrochloride dosage must be individualized and titrated to the desired clinical effect.
If a longer duration of effect is desired, additional increments can be administered intravenously or intramuscularly to maintain anesthesia. However, a higher total dose will result in a longer time to complete recovery.
Induction of Anesthesia
Intravenous Route: The initial dose of Ketamine Hydrochloride administered intravenously may range from 1 mg/kg to 4.5 mg/kg. The average amount required to produce 5 to 10 minutes of surgical anesthesia within 30 seconds following injection is 2 mg/kg. Administer Ketamine Hydrochloride slowly (i.e., over a period of 60 seconds). Rapid administration may result in respiratory depression and enhanced vasopressor response. The induction dose may be administered as an intravenous infusion at a rate of 0.5 mg/kg/min.
Intramuscular Route: The initial dose of Ketamine Hydrochloride administered intramuscularly may range from 6.5 to 13 mg/kg. A dose of 9 to 13 mg/kg usually produces surgical anesthesia within 3 to 4 minutes following injection, with the anesthetic effect usually lasting 12 to 25 minutes. Administer a benzodiazepine, if clinically indicated, for the prevention of neuropsychological manifestations during emergence from anesthesia.
Maintenance of Anesthesia
Adjust the maintenance dose according to the patient's anesthetic needs and whether an additional anesthetic agent is administered.
Repeat increments of one-half to the full induction dose as needed for maintenance of anesthesia. Purposeless and tonic-clonic movements of extremities may occur during the course of ketamine anesthesia. These movements do not imply a light plane and are not indicative of the need for additional doses of the anesthetic.
Ketamine Hydrochloride given by slow microdrip infusion technique at a dose of 0.1 to 0.5 mg/minute will maintain general anesthesia in adult patients induced with ketamine. Augment Ketamine Hydrochloride with an intravenous benzodiazepine for the prevention of neuropsychological manifestations during emergence.
Supplement to Other Anesthetic Agents
Ketamine Hydrochloride can be administered to supplement other general and local anesthetic agents. Continuously monitor patients for changes in respiratory and hemodynamic parameters.
A reduced dose of ketamine can be used to produce balanced anesthesia when used in combination with other anesthetic agents.
2.3 Preparation of Dilution
Ketamine Hydrochloride is a clear, colorless sterile solution. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Discard if product is discolored or contains particulate matter.
Induction of Anesthesia: Do not intravenously inject the 100 mg/mL concentration of Ketamine Hydrochloride without proper dilution. Dilute ketamine hydrochloride with an equal volume of either Sterile Water for injection, USP, 0.9% Sodium Chloride Injection, USP (Normal Saline), or 5% Dextrose in Water. Use immediately after dilution.
Maintenance of Anesthesia: To prepare a dilute solution containing 1 mg of ketamine per mL, aseptically transfer 10 mL from a 50 mg per mL vial or 5 mL from a 100 mg per mL vial to 500 mL of 5% Dextrose Injection, USP or 0.9% Sodium Chloride Injection, USP (Normal Saline) and mix well. The resultant solution will contain 1 mg of ketamine per mL. Use immediately after dilution.
When fluid restriction is required, Ketamine Hydrochloride can be added to a 250 mL infusion as described above to provide a ketamine hydrochloride concentration of 2 mg/mL.