Magnesium and potassium deprivation and supplementation in animals and man: aspects in view of intestinal absorption.

States of K and Mg deficiency, deprivation or depletion, are difficult to detect by determining serum concentrations, since both cations are concentrated intracellularly. The intestinal absorption of K is rather quick and complete; the uptake of Mg probably comprises two mechanisms and proceeds continuously, although incomplete. The resulting different pharmakokinetic behavior must be kept in mind when K and Mg are supplemented by the oral route. Favorable effects of oral K and Mg supplementation are reviewed, and the fact is stressed that the body cannot retain K, unless the Mg status is adequate. Therefore, K should be supplemented together with Mg. Drugs like amiloride not only spare K, but at the same time prevent renal losses of other important electrolytes, especially of chloride and Mg.