Plasma cortisol concentrations in dogs given cortisone or placebo by mouth

Fasted normal dogs (n = 8) were given fixed doses of cortisone acetate orally as 5 mg and 25 mg tablets; plasma cortisol concentrations were determined, and Cmax, tmax and area under the curve of plasma cortisol concentration plotted against time from zero to 12 hours were compared for the two preparations. In addition, these variables were compared when 25 mg tablets were administered with and without food. No significant difference in cortisol availability was noted for the two preparations and feeding did not apparently affect cortisone absorption. The findings in two hypoadrenocorticoid dogs were similar. Plasma cortisol concentrations in placebo-treated dogs similarly sampled showed minor fluctuations and were generally within accepted reference limits for normal dogs.