Combined treatment of trilostane and retinoic acid in dogs with Pituitary-Dependent Hypercortisolism

VIDAL PN; MICELI, DD; CASTILLO VA; PIGNATARO OP

Congreso; ECVIM congress; 2020

Pituitary-Dependent Hypercortisolism (PDH) is a severe metabolic disorder and represents 80-85% of cases of spontaneous hypercortisolism in dogs. Trilostane is a potent inhibitor of an early stage of adrenal steroidogenesis, but has no therapeutic effects on pituitary tumor. Retinoic acid (RA) inhibits proliferation, invasion and tumor growth, reducing ACTH production and tumor size. The aim of this study was to evaluate the combined effect of trilostane and RA to control hypercortisolism and tumor growth. In this prospective study, 8 dogs with PDH with ?partial response? to trilostane -persistence of clinical signs and biochemical abnormalities- were included. The diagnosis of PDH was made according to: clinical signs, urine cortisol creatinine ratio (UCCR), low-dose dexamethasone suppression test, plasma ACTH, abdominal ultrasound and MRI. Dogs received RA (2 mg/Kg/day) for 6 months, while continuing with trilostane (3-4 mg/Kg/12hrs). The concentrations of ACTH, cortisol, UCCR and routine laboratory were evaluated at the beginning of trilostane treatment, at the beginning of combined treatment of trilostane with RA, and at 3 and 6 months of combined treatment. MRI was performed at the beginning of the combined treatment and at 6 months. Statistical analysis performed by Wilcoxon test, expressed as median and ranges (p