磷黴素氨丁三醇
Fosfomycin
cis-1, 2-epoxyphosphonic acid
別名: Monurol · MK-955 · phosphomycin · phosphonomycin · fosfomicina · fosfomycine · fosfomycinum · fosfomysiini · fosfomycin trometamol
由 VetSheet 獸醫團隊審訂更新於 2026年4月5日本內容以實證獸醫文獻為本
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。
各物種劑量
🌎 NA — North America🌍 EU — Europe
狗
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Urinary Tract Infection (MDR E. coli) | 40 mg/kg | PO | Single dose | Single dose | 🌎 NA |
- Urinary Tract Infection (MDR E. coli): Investigational. Dose based on disodium salt in a PK study. Use should be prudently reserved for MDR E. coli based on susceptibility testing only when no other alternative exists.
馬
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Susceptible infections (Investigational) | 20 mg/kg | SC | q10h | Unknown | 🌎 NA |
- Susceptible infections (Investigational): Based on PK study using fosfomycin disodium (not commercially available in USA). May maintain effective plasma concentrations for up to 10 hours.
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。
概覽
磷黴素是一種獨特的合成廣效膦酸衍生物抗生素。最初從弗氏鏈黴菌 (Streptomyces fradiae) 中分離出來，在人類醫學中主要作為單劑量療法用於治療單純性泌尿道感染 (UTI)。
在獸醫學中，其使用仍處於高度試驗階段，但作為以下情況的「救援」或後備抗菌藥物正受到關注：
- 多重抗藥性 (MDR) 大腸桿菌 (Escherichia coli)
- 產生廣效性乙內醯胺酶 (ESBL) 的腸桿菌科細菌
- 難治性腸球菌感染
臨床要點：
- 它主要是一種時間依賴性殺菌劑，但也表現出一些濃度依賴性特徵。
- 通常不會與乙內醯胺類或氨基醣苷類藥物產生交叉抗藥性，這使其在標準第一線抗生素失效時成為有價值的選擇。
- 重要提示： 美國市售的口服製劑為氨丁三醇 (tromethamine) 鹽，而許多獸醫藥代動力學研究使用的是二鈉 (disodium) 鹽（用於腸胃外給藥）。
作用機制
Fosfomycin exerts its bactericidal effect by interfering with the very first step of bacterial cell wall (peptidoglycan) synthesis.
- It acts as a structural analogue of phosphoenolpyruvate (PEP).
- It irreversibly binds to and inhibits the cytosolic enzyme MurA (UDP-N-acetylglucosamine enolpyruvyl transferase).
- Pathway: Blocks addition of PEP to UDP-N-acetylglucosamine → Prevents formation of uridine diphosphate-N-acetylmuramic acid (UDP-MurNAc) → Halts peptidoglycan synthesis → Bacterial cell lysis.
- Secondary Action: It also reduces the adherence of bacteria to uroepithelial cells, which is highly beneficial in treating UTIs.
- Resistance Mechanism: When resistance occurs, it is typically chromosomally mediated via the production of FosA or FosX enzymes, which hydrolyze and inactivate the drug.
安全性與警告
禁忌症
- Young cats (Contraindicated due to nephrotoxicity)
- Adult cats (Relative contraindication; use with extreme caution if at all)
不良反應
- Diarrhea (most common in humans)
- Gastrointestinal upset
- Renal tubular damage / Nephrotoxicity (observed in cats)
注意事項
Warning: Appears to be highly nephrotoxic in cats, causing tubular necrosis and significant increases in serum creatinine. Use is generally contraindicated in felines.
- Renal Impairment: In humans, renal dysfunction can substantially increase the drug's half-life and reduce urine levels.
- Dosing Strategy: In humans, this drug is used as a one-time dose; multiple doses do not enhance efficacy and increase the incidence of adverse events. Veterinary protocols are still investigational.
藥物相互作用
Can decrease serum concentrations and reduce urine levels of fosfomycin.
Theoretical risk of decreasing serum and urine concentrations by increasing GI motility, similar to metoclopramide.
監測
- Gastrointestinal adverse effects (diarrhea)
- Clinical signs of UTI resolution
- Urine culture and susceptibility (pre- and post-treatment)
- Urinalysis
- Renal function tests (BUN, Creatinine) especially if used off-label in cats
藥物動力學
半衰期
吸收
Fosfomycin tromethamine is rapidly converted to the free acid fosfomycin after absorption. Dogs (PO): Bioavailability ~29%, peak levels at 2 hours. Horses (SC disodium salt): Bioavailability ~85%, peak at 3.25 hours.
分佈
Distributes well into the kidneys, bladder wall, and prostate. Crosses the placenta. Volume of distribution (steady-state): ~0.7 L/kg (dogs), 0.21 L/kg (horses). Protein binding is very low.
代謝
Fosfomycin tromethamine is rapidly converted to the active free acid fosfomycin.
排除
Primarily eliminated as unchanged drug in the urine (38% of an oral dose in humans). Clearance: ~15 mL/kg/hr (dogs), 16-24 mL/kg/hr (horses).
過量
Single overdoses are most likely to cause gastrointestinal effects (e.g., severe diarrhea). In cats, overdosage or even standard doses can cause severe nephrotoxicity (tubular necrosis). Treatment should be supportive and symptomatic.
可用產品
劑型
- Oral granules (3 grams per packet)
人用標示
- Fosfomycin Tromethamine 3 grams per packet (for dilution and oral use) (Monurol)
各地核准狀態
暫無法規資料: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
儲存與穩定性
Fosfomycin tromethamine granules should be stored at room temperature (25°C).
飼主須知
重要提示： 此藥物通常保留用於其他抗生素無效的高度抗藥性感染。請務必嚴格遵循獸醫的指示。
- 給藥方式： 如果提供的是人用顆粒劑（小包裝），請在給寵物服用前，立即將單劑量小包的全部內容物溶解在半杯（90-120 毫升）的冷水或室溫水中。請勿使用熱水。
- 食物： 可與食物一起或空腹給藥。如果引起腸胃不適，與少量零食或餐點一起餵食可能會有幫助。
- 副作用： 最常見的副作用是腹瀉。如果您的寵物出現嚴重或帶血的腹瀉、嘔吐或食慾不振，請聯繫您的獸醫。
- 毒性警告： 此藥物對貓的腎臟具有高毒性。如果您的貓在特殊情況下被開立此藥物，請極度密切監測其口渴、排尿或精神狀態的變化，並務必按時進行所有安排的血液檢查。
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