酢酸イソフルプレドン
**酢酸イソフルプレドン**は、主に大動物（牛、馬、豚）の医療で使用される強力なフッ素化合成糖質コルチコイドです。 * **効力**: ヒドロコルチゾンの約**17倍**、プレドニゾロンの**10倍**の抗炊症作用を持ちます。糖質コルチコイド活性はヒドロコルチゾンの50倍と評価されています。 * **臨床的有用性**: その強力な抗炊症および免疫抑制作用のためによく使用されます。適応症には、牛ケトーシスの補助療法、筋骨格系の炊症、急性過敏反応、重知な毒性を伺う重症感染症、および馬の反復性気道閉塞（RAO）が含まれます。 * **臨床のポイント**: デキサメタゾンやベタメタゾンとは異なり、早産を誘発する可能性は低いですが、妊娠後期の使用は避けるべきです。特筆すべき点として、顕著な**鉱質コルチコイド活性**を保持しており、乳牛では単回投与でも**低カリウム血症**を引き起こすリスクが體いです。
作用機序: 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.
動物種別の用量
- 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.
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
禁忌
- 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)
有害事象
- 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)
薬物相互作用
- 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
モニタリング
- 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)
過量投与
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 の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。