Pharmacotherapeutic group: progestagen
ATC vet code: QG03D
Pharmacodynamic properties
Flugestone acetate is a synthetic analogue of progesterone. It is approximately 20 fold more potent than progesterone and displays progestational activity but no anti-progestational, anti-androgenic or androgenic properties together with a low glucocorticoid activity.
Owing to its binding to the progesterone receptors, flugestone acetate acts by negative feedback on the hypothalamo-pituitary axis, suppressing pituitary release of gonadotropins and therefore terminal follicular growth and ovulation.
Pharmacokinetic properties
Flugestone acetate is readily absorbed during the 12-14 days period of intra-vaginal administration. Tmax ranges between 8 and 24 h, whereas Cmax varies between 1.4 and 3.7 ng/ml. Steady state is reached quickly following onset of the treatment. Plasma cronolone concentrations are relatively constant throughout treatment. One day after removal of the Chronogest CR, flugestone acetate concentrations have dropped below the limit of quantification (LOQ = 0.04 ng/ml).
Flugestone acetate is metabolised into hydroxylated metabolites, which are excreted in faeces and urine.