DOSAGE AND ADMINISTRATION
Parenteral drug products should be inspected visually for
particulate matter and discoloration prior to administration, whenever solution
and container permit.
Note: Barbiturates and ketamine, being chemically incompatible because
of precipitate formation, should not be
injected from the same syringe.
If the ketamine dose
is augmented with diazepam, the two drugs must be given separately. Do not
mix ketamine hydrochloride and diazepam in syringe or infusion flask. For
additional information on the use of diazepam, refer to the WARNINGS and DOSAGE AND ADMINISTRATION sections
of the diazepam insert.
While vomiting has been reported following ketamine administration,
some airway protection may be afforded because of active laryngeal-pharyngeal
reflexes. However, since aspiration may occur with ketamine and since protective
reflexes may also be diminished by supplementary anesthetics and muscle relaxants,
the possibility of aspiration must 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.
Onset and Duration
of rapid induction following the initial intravenous injection, the patient
should be in a supported position during administration.
onset of action of ketamine is rapid; an intravenous dose of 2 mg/kg (1 mg/lb)
of body weight usually produces surgical anesthesia within 30 seconds after
injection, with the anesthetic effect usually lasting five to ten minutes.
If a longer effect is desired, additional increments can be administered intravenously
or intramuscularly to maintain anesthesia without producing significant cumulative
Intramuscular doses, in a range of 9 to13 mg/kg
(4 to 6 mg/lb) usually produce surgical anesthesia within 3 to 4 minutes
following injection, with the anesthetic effect usually lasting 12 to 25 minutes.
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
dosage recommendation cannot be absolutely fixed. The drug should be titrated
against the patient’s requirements.
Route: The initial dose of ketamine administered intravenously may
range from 1 mg/kg to 4.5 mg/kg (0.5 to 2 mg/lb). The average amount
required to produce five to ten minutes of surgical anesthesia has been 2
mg/kg (1 mg/lb).
Alternatively, in adult patients an
induction dose of 1 mg to 2 mg/kg intravenous ketamine at a rate of 0.5 mg/kg/min
may be used for induction of anesthesia. In addition, diazepam in 2 mg to
5 mg doses, administered in a separate syringe over 60 seconds, may be
used. In most cases, 15 mg of intravenous diazepam or
less will suffice. The incidence of psychological manifestations
during emergence, particularly dream-like observations and emergence delirium,
may be reduced by this induction dosage program.
Note: 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, Sodium Chloride Injection, 0.9% or
Dextrose Injection, 5%.
of Administration: It is recommended that ketamine be administered
slowly (over a period of 60 seconds). More rapid administration may result
in respiratory depression and enhanced pressor response.
Intramuscular Route: The initial dose of ketamine
administered intramuscularly may range from 6.5 to 13 mg/kg (3 to 6 mg/lb).
A dose of 10 mg/kg (5 mg/lb) will usually produce 12 to 25 minutes of surgical
The maintenance dose should be
adjusted according to the patient’s anesthetic needs and whether an
additional anesthetic agent is employed.
of one-half to the full induction dose may be repeated as needed for maintenance
of anesthesia. However, it should be noted that 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 the anesthetic.
It should be recognized
that the larger the total dose of ketamine administered, the longer will be
the time to complete recovery.
Adult patients induced
with ketamine augmented with intravenous diazepam may be maintained on ketamine
given by slow microdrip infusion technique at a dose of 0.1 to 0.5 mg/minute,
augmented with diazepam 2 to 5 mg administered intravenously as needed. In
many cases 20 mg or less of intravenous
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
prepare a dilute solution containing 1 mg of ketamine per mL, aseptically
transfer 10 mL (50 mg per mL vial) or 5 mL (100 mg per mL vial) to 500
mL of Dextrose Injection, 5% or Sodium Chloride Injection, 0.9% and mix well.
The resultant solution will contain 1 mg of ketamine per mL.
fluid requirements of the patient and duration of anesthesia must be considered
when selecting the appropriate dilution of ketamine hydrochloride injection.
If fluid restriction is required, ketamine hydrochloride injection can be
added to a 250 mL infusion as described above to provide a ketamine concentration
of 2 mg/mL.
Ketamine is clinically compatible with
the commonly used general and local anesthetic agents when an adequate respiratory
exchange is maintained.
The regimen of a reduced dose
of ketamine supplemented with diazepam can be used to produce balanced anesthesia
by combination with other agents such as nitrous oxide and oxygen.