醋酸異氟潑尼龍
**醋酸異氟潑尼龍 (Isoflupredone acetate)** 是一種強效的含氟合成糖皮質素，主要於大型動物（牛、馬和豬）醫學中使用。 * **效力**：其抗發炊效力約為氫化可的松的 **17 倍**，潑尼松龍的 **10 倍**。其糖皮質素活性評估為氫化可的松的 50 倍。 * **臨床應用**：常用於其顯著的抗發炊和免疫抑制作用。標示適應症包括牛酮體症的輔助治療、肌肉骨骼發炊、急性過敏反應、伴隨嚴重毒性的嚴重感染，以及馬匹的復發性呼吸道阻塞 (RAO)。 * **臨床珍珠**：與地塞米松或倍他米松不同，異氟潑尼龍較不易引發早產，但在懷孕後期仍應避免使用。值得注意的是，它保留了顯著的**礦物皮質素活性**，使患者極易出現**低血鉀**，即使在乳牛中僅使用單一劑量也可能發生。
作用機制: Isoflupredone exerts its effects via classic genomic and non-genomic steroid pathways: * **Anti-inflammatory (Glucocorticoid Receptor - GR)**: Binds to cytosolic **GR** → translocates to the nucleus → induces transcription of **lipocortin-1 (annexin A1)**. Lipocortin-1 inhibits **phospholipase A2**, thereby blocking the release of arachidonic acid and halting the production of inflammatory prostaglandins and leukotrienes. It also transrepresses pro-inflammatory transcription factors like **NF-κB** and **AP-1**. * **Mineralocorticoid Effects (Mineralocorticoid Receptor - MR)**: Binds to **MR** in the distal renal tubules → upregulates Na+/K+ ATPase and ENaC channels → promotes **sodium retention** and **potassium excretion** (leading to hypokalemia). * **Metabolic**: Stimulates hepatic gluconeogenesis (useful in bovine ketosis) and decreases peripheral glucose utilization.
各物種劑量
- Labeled systemic indications · 10-20 mg (total dose) · IM · repeated in 12 to 24 hours if indicated · according to the size of the animal and severity of the condition
- Labeled systemic indications · 5-20 mg (total dose) · IM · repeated as necessary
- Intrasynovial administration · 5-20 mg or more · Intrasynovial · depending on the size of the joint cavity
- Intraarticular administration · 4-20 mg · Intraarticular · has a short to medium duration of action
- Treatment of 'heaves' (RAO) · 10-14 mg (total dose) · IM · once daily · for a horse weighing between 450-500 kg
- Treatment of recurrent airway obstruction (RAO) · 0.03 mg/kg · IM · once daily · 14 days · Patients developed significant decreases in serum potassium
- Labeled systemic indications · 5 mg (total dose) · IM · for a 300 lb. animal. Adjust dose proportionally for a smaller or larger animal.
劑量為持牌獸醫專業人員的臨床參考。請務必對照最新藥品說明書及個別病患確認。
給藥途徑
禁忌症
- Systemic fungal infections (unless used for Addison's replacement)
- Idiopathic thrombocytopenia (when administered IM)
- Hypersensitivity to the compound
- Downer cows or animals susceptible to hypokalemia
- Calves to be processed into veal
- Late stages of pregnancy (relative contraindication)
不良反應
- Hypokalemia (even with single doses)
- Reduced milk production
- Delayed wound healing
- Gastrointestinal ulceration
- Increased infection rates
- Diabetes mellitus exacerbation / hyperglycemia
- Pancreatitis
- Hepatopathy
- Renal dysfunction
- Osteoporosis
- Laminitis (horses)
- Hypothyroidism
- Hyperlipidemia
- Decreased growth in young animals
- Premature parturition with retained placenta (if used in late pregnancy)
藥物相互作用
- Digitalis glycosides (digoxin) · Increased chance of digitalis toxicity may occur should hypokalemia develop; diligent monitoring of potassium and digitalis glycoside levels is recommended
- Potassium-depleting diuretics (furosemide, thiazides) · Administered concomitantly with glucocorticoids may cause hypokalemia
- Salicylates · Glucocorticoids may reduce salicylate blood levels
- Ulcerogenic drugs (e.g., NSAIDs) · With glucocorticoids may increase the risk of gastrointestinal ulceration
- Vaccines, toxoids, bacterins · A diminished immune response may occur; patients receiving immunosuppressive dosages should generally not receive live attenuated-virus vaccines
監測
- Efficacy and adverse effects
- Serum potassium (highly recommended due to hypokalemia risk)
- Renal and liver function
- CBC
- Blood glucose
- Serum electrolytes
- ACTH stimulation tests (to determine HPA axis suppression)
- Thyroid hormone monitoring (if use is prolonged)
過量
A single overdose of isoflupredone is unlikely to cause harmful effects. Should clinical signs require intervention, use supportive treatment. Chronic usage of glucocorticoids can lead to serious adverse effects, generally manifested as signs of hyperadrenocorticism.
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。