Efficacy of oral mifepristone and parenteral Aglepristone on serum progesterone concentration and clinical recovery in female dogs with pyometra

The present study evaluated the comparative therapeutic efficacy of oral and parenteral progesterone receptor antagonists, specifically Mifepristone and Aglepristone for the medical management of open canine pyometra. The investigation involved twelve female dogs of various breeds, aged between 3.5 to 9.0 years (6.25±0.45 years) diagnosed with pyometra. The animals were randomly divided into two treatment groups. Group I (n = 6) received oral Mifepristone (@ 2.5 mg/kg B.W.) on days 1, 2 and 7, while Group II (n = 6) received subcutaneous Aglepristone (@ 10 mg/kg B.W.) on the same schedule. Prominent clinical signs at presentation included purulent vaginal discharge (100%), polydipsia (91.67%), lethargy/anorexia (83.33%) and pyrexia (83.33%). Physiological parameters indicated systemic stress with initial pyrexia observed in all dogs alongside elevated heart rates. Following treatment, clinical signs resolved effectively; pyrexia and tachycardia normalized significantly from day 7 onwards in both groups. Group II exhibited a significantly faster decline in serum progesterone concentration from a baseline (29.12±4.10 ng/mL) to basal concentrations (0.31±0.16 ng/mL) by day 14 compared to Group I which decreased from a baseline of 24.96±2.02 ng/mL to 6.96±1.46 ng/mL over the same period. It is concluded that while both progesterone receptor antagonist protocols effectively resolved the clinical symptoms and restored physiological parameters, the parenteral Aglepristone demonstrated superior efficacy in suppressing luteal function and accelerating recovery.