Adults and Children 16 yr of age and older:IV Initial: 1 to 4.5 mg/kg via slow infusion (over 60 sec); usual dose for 5- to 10-min anesthesia: 2 mg/kg. Alternatively, 1 to 2 mg/kg at a rate of 0.5 mg/kg/min, augmented with diazepam IV 2 to 5 mg. Maintenance: One-half to full induction dose, repeated as needed. Alternatively, adults induced with ketamine augmented with IV diazepam may receive 0.1 to 0.5 mg/min by slow microdrip infusion, augmented with diazepam 2 to 5 mg IV as needed. IM Initial: 6.5 to 13 mg/kg. Maintenance: One-half to full induction dose, repeated as needed.
Produces rapid-acting anesthetic state with profound analgesia, normal pharyngeal-laryngeal reflexes, normal or slightly enhanced skeletal muscle tone, cardiovascular and respiratory stimulation, and, occasionally, transient and minimal respiratory depression.
CV: Arrhythmia, bradycardia, elevated blood pressure and heart rate, hypotension. CNS: Enhanced skeletal muscle tone manifested by tonic and clonic movement.
Confusion, delirium, excitement, hallucinations, irrational behavior, pleasant dream-like state, vivid imagery. DERM: Morbilliform rash, transient erythema. EENT: Diplopia, increased intraocular pressure, nystagmus. GI: Anorexia, nausea, vomiting. LOCAL: Local pain and exanthema at injection site. RESP: Apnea after rapid injection, laryngospasm, other airway obstruction, respiratory stimulation, severe respiratory depression. WARNING:
Emergence reactions occur in approximately 12% of patients. The incidence is least frequent in elderly (older than 65 yr of age) patients and also less frequent with IM use.
Severity varies between pleasant dream-like states, vivid imagery, hallucinations, and emergence delirium, sometimes accompanied by confusion, excitement, and irrational behavior. The duration is ordinarily a few hours; however, recurrences have been seen up to 24 h postoperatively. No residual psychological effects are known. The incidence may be reduced by using lower dosages with IV diazepam. These reactions may be reduced if verbal, tactile, and visual patient stimulation is minimized during recovery. This does not preclude monitoring vital signs.
To terminate a severe emergence reaction, a small hypnotic dose of a short-acting or ultra short-acting barbiturate may be required. When used on an outpatient basis, do not release patient until recovery from anesthesia is complete. Patients should be accompanied by an adult.