Cloprostenol Sodium
Cloprostenol sodium is a synthetic **prostaglandin F2α (PGF2α) analogue** widely used in veterinary medicine primarily for its potent **luteolytic** properties. It is structurally related to naturally occurring dinoprost but is significantly more potent and has a longer duration of action. * **Large Animals:** It is a staple in bovine, equine, and swine reproduction for estrus synchronization, inducing parturition, and managing reproductive pathologies such as luteal cysts, mummified fetuses, or chronic endometritis. * **Small Animals:** In dogs, it is used off-label for pregnancy termination and the medical management of open-cervix pyometra. **Clinical Pearl:** Because it is a synthetic analogue, cloprostenol often exhibits fewer systemic side effects in horses compared to natural PGF2α (dinoprost), though dogs may still experience significant cholinergic-like adverse effects (which can be mitigated by pre-treatment with anticholinergics like atropine).
กลไกการออกฤทธิ์: Cloprostenol acts as a potent agonist at **prostaglandin F (FP) receptors**. * **Luteolysis:** Binds to FP receptors on the **corpus luteum (CL)** → induces rapid functional and structural regression (luteolysis) → sharp decline in **progesterone** production. This drop in progesterone removes the negative feedback on the hypothalamus/pituitary, allowing a return to estrus, or induces abortion/parturition depending on the stage of gestation. * **Myometrial Contraction:** Directly stimulates FP receptors on **uterine smooth muscle** → increases intracellular calcium → powerful, rhythmic uterine contractions (ecbolic effect). * **Cervical Relaxation:** Concurrently promotes relaxation and dilation of the cervix, facilitating the expulsion of uterine contents (e.g., fetus, purulent material in pyometra).
ขนาดยาตามชนิดสัตว์
- To induce parturition in does · 62.5-125 micrograms · IM · once · Give at 144 days of gestation in early morning. Deliveries will peak at 30-35 hours after injection. Maintain goat in usual surroundings and minimize outside disturbances.
- To treat pseudopregnancy (hydrometra/mucometra) · 125 micrograms · IM · once
- For treatment of pyometra · 500 micrograms · IM · once · Up to 97% efficacy.
- For pyometra or chronic endometritis, mummified fetus, luteal cysts · 500 micrograms · IM · once · Manual assistance may be required to remove mummified fetus from vagina.
- For unobserved or undetected estrus in cows with continued ovarian cyclicity and a mature corpus luteum · 500 micrograms · IM · once · Estrus should commence in 2-5 days at which time the animal may be inseminated. If estrus detection is not possible, inseminate twice at 72 and 96 hours post injection.
- For abortion, from one week after mating to approximately the 150th day of gestation · 500 micrograms · IM · once · Abortion generally takes place in 4-5 days after injection.
- For controlled breeding (Single injection method) · 500 micrograms · IM · once · Use only animals with mature corpus luteum. Inseminate at usual time after detecting estrus, or once at 72 hours, or twice at 72 and 96 hours post injection.
- For controlled breeding (Double injection method) · 500 micrograms · IM · Repeat dose 11 days later · Estrus should occur in 2-5 days after second injection.
วิธีการให้ยา
ข้อห้ามใช้
- Pregnancy (when abortion or induced parturition are not desired)
- Intravenous (IV) administration
อาการไม่พึงประสงค์
- Increased salivation (dogs)
- Tachycardia (dogs)
- Increased urination and defecation (dogs)
- Gagging and vomiting (dogs)
- Ataxia and mild depression (dogs)
- Sweating (horses)
- Cramping and loose stools (horses)
- Increased risk of dystocia if used after 5th month of gestation (cattle)
อันตรกิริยาระหว่างยา
- Oxytocic agents · Activity may be enhanced by cloprostenol
การติดตาม
- Resolution of clinical signs (e.g., clearance of pyometra)
- Estrus behavior and timing
- Confirmation of pregnancy termination/abortion
- Adverse cholinergic effects in dogs (salivation, vomiting, heart rate)
การได้รับยาเกินขนาด
In **cattle**, doses of 50 and 100 times those recommended may cause signs of uneasiness, slight frothing, and milk let-down. In **small animals**, overdoses of cloprostenol or other synthetic prostaglandin F2α analogs reportedly can result in severe shock and death.
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