EFFECT OF BARBITURATE ON CENTRAL PAIN - DIFFERENCE BETWEEN INTRAVENOUS ADMINISTRATION AND ORAL-ADMINISTRATION

Objective: To examine whether the oral administration of barbiturates is of clinical use in a patient with central pain. Setting: Pain Clini c, Osaka University Medical Hospital, Osaka, Japan. Patient: A patient with central pain after loss of his left upper extremity, Interventio ns: A 50-mg dose of intravenous amobarbital, which produced a plasma c oncentration of 2.5-4.0 mu g/ml, was effective in reducing the central pain. Subsequently, doses of 300-400 mg/day were administered orally: these succeeded in achieving similar plasma concentration levels. Res ults and Conclusions: Oral administration of barbiturate did not allev iate central pain, even when the plasma concentration was the some as the effective level in intravenous use. Pharmacokinetic and pharmacody namic factors more complex than simple plasma concentrations may he in volved in producing the difference in the effects.