[Comparative pharmacological effectiveness of dexamethasone esters in pigs (author's transl)]

Leucocytosis with neutrophilia, lymphopenia and eosinopenia, and decreases in plasma endogenous glucocorticoid levels were used to study the pharmacological kinetics of dexamethasone in pigs. The return to baseline of endogenous plasma glucocorticoid levels was the most sensitive index of dexamethasone action. Intravenous administration of 38 microgram/kg of the soluble phosphate ester produced a maximal response. Higher dosages (76 and 152 microgram/kg) did not increase the intensity of the response, but did increase its duration, which was less than 24 hours. The same response was obtained when dexamethasone phosphate (75 microgram/kg) was given by the intramuscular route. Insoluble esters had a weaker but longer action which lasted for 28 hours with terethoxy-acetate, and approximatively 48 hours with acetate and isonicotinate, on the basis of the pituitary-adrenal axis inhibition. After intramuscular administration, dexamethasone esters induced a weak hyperglycemia but no changes in plasma sodium, chloride or calcium levels were observed.