Treatment and Long-Term Follow-up of 205 Dogs With Hypoadrenocorticism

Results of long-term treatment were evaluated in 200 dogs with primary hypoadrenocorticism and 5 dogs with spontaneous secondary hypoadrenocorticism. Fludrocortisone acetate initially was used for mineralocorticoid replacement in 190 of the dogs with primary hypoadrenocorticism. The daily dose of fludrocortisone required in these dogs increased significantly during the treatment period (median, 2.6 years) from an initial median dose of 13.1 μg/kg to a final dose of 22.6 μg/kg. In 27 of the 200 dogs, mineralocorticoid therapy was changed from fludrocortisone to desoxycorticosterone pivalate (DOCP) because of adverse effects, poor response, or financial considerations. The dose of DOCP required in the 33 dogs (27 dogs plus 6 dogs initially given DOCP) increased significantly during the treatment period (median, 3.5 years) from an initial median dose of 1.56 mg/kg to a final dose of 1.69 mg/kg; the interval between DOCP injections ranged from 14 to 35 days (median, 30 days). The dose of prednisone administered to the dogs with primary hypoadrenocorticism decreased significantly from an initial median dose of 0.3 mg/kg to a final dose of 0.2 mg/kg; the drug was discontinued in 22 dogs due to adverse effects. The 5 dogs with secondary hypoadrenocorticism received only glucocorticoid replacement therapy (prednisone) at initial and final daily dosages of 0.41 mg/kg and 0.25 mg/kg, respectively, during a median treatment period of 4.4 years. More than 80% of the dogs were considered to have a good to excellent response to therapy. The median survival time of all 205 dogs was 4.7 years. There were no differences in response to treatment or survival between dogs treated with fludrocortisone and those receiving DOCP, or between dogs with primary hypoadrenocorticism and those with secondary hypoadrenocorticism.