EFFECT OF PITRESSIN IN CIRCULATORY COLLAPSE INDUCED BY SODIUM NITRITE

Abstract

Pitressin in man was ineffective in exptl. collapse induced by NaNO2 and tilting, because it did not cause an increase in venous tone, and because the arteriolar constriction produced by the drug tended further to reduce tissue blood flow. The intramusc. inj. of 1 cc. of pitressin, with subsequent tilting of the subject to the upright position, produced collapse ending in syncope in 2 of the 6 normal subjects tested. In 2 subjects in whom collapse was induced in the upright position by the adm. of NaN02, pitressin did not prevent the development of collapse and in 1 of these it hastened it. In 1 subject, in whom neither NaNO2 nor pitressin in the upright position produced collapse, NaN02 followed by pitressin induced profound collapse ending in syncope. In still another subject neither NaN02 nor pitressin, singly or combined, produced syncope. Pitressin, given in doses of 0.5 or 1 cc. to normal subjects in the horizontal position, produced abdominal cramps, ashen pallor and a marked decrease in blood flow in the hand at 32[degree] and at 43[degree] C. It produced no consistent change in venous tone in the hand, heart rate or arterial pressure. Pitressin slowed the blood flow in the hand to such a degree that water at a temp. of from 43[degree] to 456 C. felt distinctly uncomfortable, and in 1 case caused the skin to be blistered at 45[degree] C. NaNO2 produced circulatory collapse and syncope in the upright position in about 50% of a large group of subjects tested. No criteria have been developed to predict the postural response of any given person to the adm. of NaNOa.