地諾前列素氨丁三醇
地諾前列素氨丁三醇是天然前列腺素F2α (PGF2α) 的氨丁三醇鹽，廣泛應用於多種動物的獸醫繁殖醫學中。 * **大型動物**：主要用作溶黃體劑，用於牛、馬、豬及小型反芻動物的發情同期化、無症狀發情治療、子宮蓄膿治療，以及作為墮胎或引產劑。 * **小型動物**：標示外用於犬貓的墮胎劑，以及作為子宮頸開放型子宮蓄膿的輔助內科療法。 > **臨床要點**：地諾前列素在犬隻的治療指數非常狹窄。其半數致死量 (LD50) 僅約為建議治療劑量的5倍，因此精確給藥與密切監測至關重要。由於安全性考量，目前針對子宮蓄膿的治療方案通常更傾向使用aglepristone合併cloprostenol或misoprostol。
作用機制: Dinoprost acts directly as a **prostaglandin F2alpha (PGF2α)** analog. * **Luteolysis**: Binds to specific PGF2α receptors on the corpus luteum → inhibits steroidogenesis → induces structural and functional regression of the corpus luteum (luteolysis) → rapid decline in serum progesterone levels. * **Myometrial Contraction**: Directly stimulates myometrial smooth muscle activity → increases intracellular calcium → induces strong uterine contractions. * **Cervical Relaxation**: Promotes relaxation and dilation of the cervix, facilitating the expulsion of uterine contents (fetus or purulent material in pyometra).
各物種劑量
- Estrus synchronization · 8 mg IM on day 5 of estrous cycle and repeat in 11 days · IM · twice, 11 days apart · 11 days
- Abortifacient (first two months of pregnancy) · 10-15 mg IM · IM · once · once · Abortion takes place within 72 hours.
- Estrus synchronization · 8 mg IM on day 4 of estrous cycle and repeat in 11 days · IM · twice, 11 days apart · 11 days
- Pseudopregnancy (hydrometra/mucometra) · 5 mg IM once · IM · once · once
- Abortifacient · 5-10 mg IM throughout entire pregnancy · IM · once · once · Abortion takes place in 4-5 days.
- Induce parturition · 2.5-20 mg on days 144-149 · IM · once · once · Higher dosage (20 mg) yields more predictable interval to delivery.
- Treatment of pyometra · Initially 0.1 mg/kg SC, then 0.25 mg/kg SC once a day for 5 days · SC · once daily · 6 days total · Give bactericidal antibiotics concurrently. Not recommended in animals >8 yrs old.
- Abortifacient · 2 mg (total dose) per cat IM once a day beginning at day 33 · IM · once daily · Not specified · Side effects include prostration, vomiting and diarrhea.
給藥途徑
禁忌症
- Pregnancy (unless abortion or induced parturition is desired)
- Intravenous (IV) administration
- Animals with bronchoconstrictive respiratory disease (e.g., asthma, 'heaves' in horses)
- Mares with acute or subacute disorders of the vascular system, GI tract, respiratory system, or reproductive tract
- Camelids (associated with acute toxicity and death)
- Relative contraindication: Closed-cervix pyometra
- Extreme caution in elderly (>8 years old) or debilitated animals, or those with severe cardiopulmonary, renal, or hepatic disease
不良反應
- Dogs/Cats: Abdominal pain, emesis, defecation, urination, pupillary dilation followed by constriction, tachycardias, restlessness, anxiety, fever, hypersalivation, dyspnea, panting. Fatalities are possible (especially in dogs). Cats may exhibit intense grooming and vocalization.
- Cattle: Infection at injection site, salivation, hyperthermia (especially at higher doses).
- Swine: Erythema, pruritus, urination, defecation, slight ataxia, hyperpnea, dyspnea, nesting behavior, abdominal muscle spasms, tail movements, increased vocalization, salivation.
- Horses: Transient decreased body temperature, sweating. Less frequently: increased respiratory and heart rates, ataxia, abdominal pain, lying down.
藥物相互作用
- Other oxytocic agents · Activity may be enhanced by dinoprost.
- Progestins · Reduced effect of dinoprost would be expected with concomitant administration.
監測
- Cardiorespiratory effects (especially in dogs and cats, particularly after higher dosages)
- Adverse effects (vomiting, diarrhea, hyperthermia, distress)
- Efficacy of treatment (e.g., ultrasound for pyometra resolution or pregnancy termination, observation for estrus)
過量
Dogs are highly sensitive to the toxic effects of dinoprost. The LD50 in the bitch is reported to be **5.13 mg/kg SC**, which is only about 5 times greater than the recommended dose used by some clinicians. In large animals (cattle, swine, horses), overdose quantities (e.g., 5-10X recommended doses) result in exaggerated adverse effects such as hyperthermia, vomiting, and severe abdominal cramping. **Treatment**: If clinical signs are severe in any species, immediate supportive and symptomatic therapy is recommended.
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