Effects of Vasoactive Drugs on Serum Electrolytes in Hypertensive and Normotensive Humans. ∗

Abstract

Summary

Trimethaphan was injected intravenously into 10 hypertensive and 7 normal subjects, and phenylephrine was injected intravenously into 7 hypertensive and 4 normal subjects. Blood pressures (auscultatory) and serum sodium, potassium, and chloride were measured before and at frequent intervals after administration of these drugs. No significant changes in serum electrolytes occurred following administration of trimethaphan or phenylephrine. These data, in conjunction with those of others, suggest that serum electrolytes may not accurately reflect alterations in electrolyte compositions of vascular structures during drug-induced changes in vasomotor activity. Vasoactive drugs may affect electrolyte compositions of extravascular structures, and, thus, influence serum electrolytes. Serum values, therefore, have little significance. Electrolyte changes within vessel walls and in their local environments may best be evaluated by direct analyses of vascular tissues.