Zycortal Symposium Proceedings

Zycortal Symposium Highlights

Susanna Spence, BSc BVetMed PhD MRCVS

What starting dose of Zycortal are we using?

Zycortal (DOCP) is licensed to be used in the treatment of dogs with primary hypoadrenocorticism, with concurrent glucocorticoid therapy, at a dose of 2.2 mg/kg subcutaneously every 25 days. The starting dose and dosing frequency were discussed and it was clear that most delegates are using a much lower starting dose, ranging from 1.5 to 2.0 mg/kg. Most delegates were using a dosing interval of every 28 days. Although this is a deviation from the data sheet, it was agreed that a four weekly dosing frequency improved owner compliance, allowing more consistent treatment of patients. It was advised that when reducing mineralocorticoid supplementation, the dose should be reduced, instead of increasing the dosing frequently the injections.

The starting dose of Zycortal in cats was also discussed, with the full 2.2 mg/kg dose being recommended every 28 days.

Measuring cortisol and confirming the diagnosis of Addison’s disease

The measurement of cortisol was discussed and the use of in-house snap tests was discouraged. It was also recommended that a lab recognised by the European Society of Veterinary Endocrinology (ESVE) Quality Assurance Scheme be used . Before performing an ACTH stimulation test, it should be ensured that there is no previous history of steroid administration. This includes topical eye and ear ointments and hormone therapies. There was variability in when ACTH stimulation tests are performed in patients with a history of prior steroid therapy. This was partly dependent on how recently steroid administration had been received and also the dose and length of therapy. It is also important to note that there is extreme variability in how the hypothalamic-pituitary-adrenal (HPA) axis is suppressed in patients who have received steroid therapy. In patients who were no longer on steroid therapy, it was recommended that the ACTH stimulation test be performed and repeated at weekly intervals until stimulation was documented, or the clinician was confident that the patient had Addison’s disease. If finances were limited then two to three weekly intervals could be used instead.

If patients were on oral prednisolone therapy at the time when an ACTH stimulation test was to be performed, then if possible, it would be advisable to drop to a physiological dose of

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