Pharmacotherapeutic group: Genito urinary system and sex hormones. Sex hormones and modulators of the genital system, progestogens
ATC Vet Code: QG03DA04
Pharmacodynamic properties
The vaginal delivery system delivers progesterone at a controlled rate across the vaginal mucosa into the blood stream. This suppresses the release of gonadotrophin releasing hormone and consequently luteinising hormone from the anterior pituitary inhibiting follicle maturation and so controlling the oestrous cycle. After removal of the device, circulating blood levels of progesterone fall precipitously, allowing follicle maturation, behavioural oestrus and ovulation.
Pharmacokinetic particulars
The pharmacokinetic profile of progesterone when administered as a single device was characterised by a maximum concentration (Cmax) in plasma of up to 5.9 ng/mL achieved post-dosing. Peak concentrations were followed by a decline in systemic exposure to a steady state of approximately 2 ng/mL. After removal of the device, circulating blood levels of progesterone fall precipitously within 2-4 hours reaching baseline levels by 12 hours.