氯前列醇鈉
氯前列醇鈉是一種合成的**前列腺素F2α (PGF2α) 類似物**，在獸醫學中主要因其強效的**黃體溶解**特性而被廣泛使用。其結構與天然的地諾前列素 (dinoprost) 相似，但效力更強且作用時間更長。 * **大型動物：** 在牛、馬和豬的繁殖管理中是常規用藥，用於發情同期化、誘導分娩，以及治療黃體囊腫、木乃伊化胎兒或慢性子宮內膜炎等生殖道病理。 * **小型動物：** 在犬類中，常以仿單標示外方式 (off-label) 用於終止妊娠及開放性子宮蓄膿的內科治療。 **臨床要點：** 由於它是合成類似物，在馬匹身上引起的全身性副作用通常少於天然 PGF2α (地諾前列素)，但犬隻仍可能出現明顯的類膽鹼性不良反應（可透過預先給予阿托品等抗膽鹼藥物來緩解）。
作用機制: 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).
各物種劑量
- 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.
給藥途徑
禁忌症
- Pregnancy (when abortion or induced parturition are not desired)
- Intravenous (IV) administration
不良反應
- 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)
藥物相互作用
- Oxytocic agents · Activity may be enhanced by cloprostenol
監測
- 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)
過量
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.
VetSheet 藥物參考供持牌獸醫專業人員作臨床決策輔助之用,不能取代專業判斷或廠方最新藥品說明書。