Cats have low bioavailability of oral prednisone compared to prednisolone, making prednisolone the preferred oral glucocorticoid in this species. Although interconversion between the two drugs occurs in cats, a single 2 mg/kg oral dose of prednisolone produces approximately 4-fold higher plasma prednisolone area under the curve compared to the same dose of prednisone. Research in Vet…
Body condition further amplifies glucocorticoid exposure in cats. Over-conditioned cats achieve approximately 2-fold higher plasma drug concentrations compared to normal-conditioned cats after the same oral dose, which likely explains their perceived increased risk for glucocorticoid-associated side effects including hepatic lipidosis and diabetes mellitus. Research in Vet… Dosing based on lean body mass or ideal body weight is recommended in over-conditioned cats. Research in Vet…
The clinical consequence of poor prednisone bioavailability is that cats require prednisolone specifically, and at higher doses than dogs for equivalent glucocorticoid effect. For long-term glucocorticoid replacement in feline primary hypoadrenocorticism, the final maintenance prednisolone dose is approximately 0.3 mg/kg/day — substantially higher than the commonly recommended 0.05 to 0.1 mg/kg/day used in dogs. Journal of Vete… The most likely explanation is reduced density of glucocorticoid receptors in feline tissue and lower binding affinity of glucocorticoids at those receptors. Journal of Vete…
Despite higher required doses, cats are more resistant than dogs to the metabolic side effects of glucocorticoids. At anti-inflammatory doses, prednisolone-treated cats show increases in monocyte count and serum albumin, cholesterol, and triglyceride concentrations, but these values remain within reference ranges (with the exception of triglycerides). American Journa… Dogs receiving comparable anti-inflammatory prednisone doses routinely exceed reference ranges and additionally develop increased alkaline phosphatase and alanine transferase activities, decreased chloride concentration, and decreased urine specific gravity — changes not observed in prednisolone-treated cats. American Journa… Anti-inflammatory doses of prednisolone do not produce clinically relevant mineralocorticoid effects in systemically normal cats. American Journa…
Monitoring for prednisolone overtreatment in cats is clinically challenging because cats typically do not show polydipsia; signs are limited to increased sleeping and weight gain. Journal of Vete… Endogenous ACTH measurement has been proposed as an adjunct to detect overtreatment, with a completely suppressed ACTH concentration during a hospital visit interpreted as a likely signal of excess glucocorticoid. Journal of Vete…
Would you like guidance on prednisolone dosing protocols for a specific feline condition — such as inflammatory bowel disease, cholangitis, or hypoadrenocorticism?