Pharmacotherapeutic group: Corticosteroids for systemic use, dexamethasone. ATC vet-code: QH02AB02.

Pharmacodynamic properties

This preparation contains the sodium phosphate ester of dexamethasone, a fluoro-methyl derivative of prednisolone, which is a potent glucocorticoid with minimal mineralocorticoid activity. Dexamethasone has ten to twenty times the anti-inflammatory activity of prednisolone.
Corticosteroids suppress the immune response by inhibition of dilatation of capillaries, migration and function of leucocytes and phagocytosis.
Glucocorticoids have an effect on metabolism by increasing gluconeogensis.

Pharmacokinetic properties

After extravascular (intramuscular, subcutaneous, intra-articular) administration, this soluble ester of dexamethsone is rapidly absorbed from the injection site following by immediate hydrolysation into the parent compound, dexamethasone.
Absorption of dexamethasone is rapid. The time to reach maximum plasma concentrations (Cmax) of dexamethasone in cattle, horse, pig and dog is within 20 min after intramuscular administration. Bioavailability following IM administration (compared to IV administration) is high in all species. Elimination half-life after intravenous administration in horses is 3.5 hours. After intramuscular administration, apparently elimination half-life has been shown to range between 1 and 20 hours according to the species.