[Intramuscular ketamine analgesia in emergency patients. I. Clinico--pharmacokinetic study]

Effective analgesia under conditions of emergency and disaster is still a problem which can be considered as unsolved. The i.m. administration of ketamine in subanaesthetic doses could be one step forward, particularly in regard to a possible application by paramedical personnel. In order to evaluate this hypothesis, we compared 2 groups of 6 patients each, who received either 0.5 mg/kg or 1 mg/kg ketamine respectively i.m. for p.o. pain relief after tonsillectomies. The analgesic efficacy, the levels of consciousness, the blood pressure values and the ketamine plasma levels demonstrated, that effective analgesia can be obtained within 10 min following either dose. The dosage of 1 mg/kg however was followed by a transient impairment of the levels of consciousness. The pharmacokinetic data may lead to the conclusion that analgesia starts above plasma levels of 100 ng/ml. Important side effects were not be observed in these few cases. A further study, which has almost been completed, will demonstrate whether the same results apply to emergency out-patients suffering from fractures, burns etc.