Pharmacology and Mechanism of Action
Cloprostenol is a snythetic prostaglandin, structurally related to PGF2 -alpha, that produces PGF2-alpha effects. Prostaglandin F2 analogues have a direct luteolytic action on the corpus leuteum. After injection, cloprostenol causes functional regression of the corpus luteum (Luteolysis). In nonpregnant cycling cattle, this effect will result in starting estrus 2 to 5 days after injection. In pregnant animals, it will terminate the pregnancy. In animals with a prolonged luteal activity that has a pyometra, mummified fetus, or luteal cysts, the luteolysis usually results in resolution of the problem and return to normal cycling.
Indications and Clinical Uses
Cloprostenol has been used in cattle to induce luteolysis (beef and dairy cattle) to manipulate the timing of the estrus cycle to benefit breeding management practices. It also can be used to terminate pregnancy resulting from undesired mating and to treat conditions associated with prolonged luteal function (e.g.,
pyometra, luteal cysts). Cloprostenol has been used to terminate pregnancy in any animal that forms a corpus luteum. In dogs, cloprostenol has been administered in combination with other drugs (e.g.,
cabergoline and bromocriptine to terminate pregnancy. When used to terminate pregnancy, it has been almost 100% effective.
Adverse Reactions and Side Effects
Induces abortion in pregnant animals. High doses in cattle have caused discomfort, milk letdown, and some frothing. To avoid vomiting, it is recommended to wait 8 hours after feeding. Abortion may be followed by 1 week (approximately) of mucoid vulvar discharge. Mammary enlargement and mild milk production may occur in some dogs.
To be used only by licensed veterinarians.