Alteration of Anesthetic Requirement by Amphetamine

Abstract

The effects of acute and chronic administration of dextroamphetamine (DA) on halothane MAC in dogs were evaluated. Acute intravenous administration of DA, 0.1, 0.5, and 1 mg/kg, during halo thane anesthesia was associated with increases of MAC to 19 ±8, 67 ± 11, and 96 ± 15 per cent above control values. Blood pressure increased 40, 112, and 109 per cent, respectively, at the three dose levels, and in 12 of 15 acute-administration trials the dogs developed cardiac arrhythmias. Body temperature increased 0.4 to 2.1 C following acute administration of DA. The large change in MAC produced by interaction of DA with halothane could be decreased by respiratory alkalosis. In contrast, chronically-treated dogs receiving 5 mg/kg/day of DA intramuscularly for seven days had decreases in MAC of 21 ± 3 per cent from control values. These data support the hypothesis that catecholamines that act on the central nervous system may alter anesthetic requirements.