OBSERVATIONS ON THE EFFECT OF MAGNESIUM ON BLOOD COAGULATION BY

Previous observations on the effect of oral magnesium and peptone on thrombin generation time are examined. The smallest amounts of magnesium and peptone regularly producing a significant shift demonstrable after one hour are 0.25 g. magnesium and 15 g. peptone. The oral effect can be reproduced by the intravenous injection of magnesium. The minimum amount required is 50 mg. The effect is transient, and after 30 minutes can no longer be demonstrated. Amounts of magnesium of the same order as those acting on intravenous injection can produce a shift of thrombin generation time in vitro. This action of magnesium in vitro can be antagonized by the addition of calcium. Small amounts of magnesium added to fresh unclotted human plasma prolong the clotting time considerably. This action was shown to be due to an antagonism between Mg++ and Ca++, both competing for combination with clotting factors (Greville and Lehmann, 1944). Suc