Objective: To evaluate effects of iatrogenic hyperadrenocorticism on plasma cortisol concentrations produced by an infusion of hydrocortisone in dogs.
Procedure: Plasma cortisol concentrations were measured regularly during a 6 h infusion of hydrocortisone sodium succinate at two dose rates. The infusions were performed before and after treatment for 30 d with oral cortisone acetate at 10 mg/kg/24 h, divided thrice daily. Adrenal activity during the experimental period was assessed by weekly ACTH stimulation tests.
Results: Both infusion rates produced lower plasma cortisol concentrations after treatment for 30 d with cortisone.
Conclusion: Prior exposure to high concentrations of glucocorticoids may result in accelerated metabolism of glucocorticoids administered subsequently. This may necessitate increased dosages when using glucocorticoids to support inadequate adrenal function.