Hemodynamic effects of massive doses of dexamethasone in controlled hypovolemic shock in the dog

The hemodynamic effects of massive doses of dexamethasone in combination with the alpha-adrenergic blocking agent phenoxybenzamine were studied in dogs subjected to hemorrhagic hypotension. Previously it has been shown that the glucocorticoid methylprednisolone, but not the glucocorticoid betamethasone, induces a pronounced vasodilation in combination with phenoxybenzamine. In the present study it was found that also dexamethasone (a stereoisomer of betamethasone) is unable to increase the peripheral blood flow after phenoxybenzamine. Since equivalent doses were used in relation to glucocorticoid activity, it seems reasonable to conclude that the different hemodynamic patterns are unrelated to the glucocorticoid ability of the drugs. Furthermore, it is unlikely that possible beneficial effects of dexamethasone in hypovolemic shock are due to a direct vascular influence.