Thermal stability of prehospital medications.

To evaluate the effect of prolonged environmental extremes on common prehospital medications, four identical sets of 23 drugs were placed in a simulated environment for up to four weeks. Subsequently, the samples were analyzed by gas chromatography-mass spectrometry for evidence of degradation byproducts. Twenty-one of the 23 samples showed no breakdown products; however, isoproterenol demonstrated 11% loss of parent compound after four weeks of environmental exposure. Epinephrine manifested a change in its ionized state after exposure to heat; the physiologic effect of this change was not determined. Our results suggest that rural and suburban emergency medical services providers, whose medications may not be replaced until they are used in patient care, must monitor their drug boxes' duration of exposure to uncontrolled conditions.