Pharmacotherapeutic group: Genito urinary system and sex hormones, other gynecologicals, uterotonics, prostaglandins.
ATCvet code: QG02AD90.
Pharmacodynamic properties
Cloprostenol sodium is a (racemic) analogue of prostaglandin F2α (PGF2α), for use in cattle.
This product is a potent luteolytic agent. It causes functional and morphological regression of the corpus luteum (luteolysis) in cattle followed by return to oestrus and normal ovulation.
Furthermore, this group of substances has a contractile effect on the smooth muscles (uterus, gastro-intestinal tract, respiratory tract, vascular system).
The drug does not demonstrate any androgenic, oestrogenic or anti progesterone activity and its effect on pregnancy is due to its luteolytic property.
At pharmacological doses, no obvious ill effects have been observed. Unlike other prostaglandin analogues, cloprostenol has no thromboxane A2 activity and does not cause platelet aggregation.
Cloprostenol does not impair fertility. No deleterious effects have been reported on the progeny conceived at the oestrus following treatment.
Pharmacokinetic particulars
Metabolism studies, using 15 - 14C-closprostenol have been performed in cattle (by im administration) to determine residue levels. The kinetics of cloprostenol following oral administration were not determined.
The kinetic studies indicate that the compound is rapidly absorbed from the site of injection, is metabolised followed by excretion in approximately equal proportion in urine and faeces. In the cow, a major portion of the dose is excreted within 0-4 hours and most of the dose is eliminated within 24 hours. The major route of metabolism appears to be β-oxidation to the tetranor or dinor acids of cloprostenol. Peak values of radioactivity in blood were observed within 1 hour of a parenteral dose and declined with a t ½ of between 1 - 3 hours depending on species.