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苯唑西林

Oxacillin

Oxacillin sodium

抗生素 - 抗葡萄球菌青黴素POIMIVSC狗貓馬

別名: Bactocill · Sodium oxacillin · Methylphenyl isoxazolyl penicillin · Oxacillinum natricum · P-12 · SQ-16423

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

22-40 mg/kg PO, SC, IM, or IV q8hPO, SC, IM, IV· q8h
— 🐕

劑量為合格獸醫專業人員的臨床參考。請務必對照最新仿單及個別病患確認。

各物種劑量

🌎 NA — North America🌍 EU — Europe

狗

適應症劑量途徑頻次療程地區
Susceptible infections22-40 mg/kg PO, SC, IM, or IV q8hPO, SC, IM, IVq8h—🌎 NA

貓

適應症劑量途徑頻次療程地區
Susceptible infections22-40 mg/kg PO, SC, IM, or IV q8hPO, SC, IM, IVq8h—🌎 NA

馬

適應症劑量途徑頻次療程地區
Susceptible infections20-30 mg/kg IV q6-8hIVq6-8h—🌎 NA
Susceptible infections25-50 mg/kg IM, IV twice dailyIM, IVq12h—🌎 NA
  • Susceptible infections: Dose extrapolated from adult horse data; use lower dose or longer interval in premature foals or those less than 7 days old.

劑量為合格獸醫專業人員的臨床參考。請務必對照最新仿單及個別病患確認。

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概覽

苯唑西林（Oxacillin）是一種窄效的​抗β-內醯胺酶（抗葡萄球菌）青黴素​。

  • ​臨床用途​：主要用於治療由產青黴素酶的葡萄球菌（如MSSA、MSSP）引起的骨骼、皮膚及軟組織感染。
  • ​抗菌譜​：對革蘭氏陽性球菌高度有效。對立克次體、分枝桿菌、黴菌、黴漿菌、病毒及多數革蘭氏陰性菌無效。
  • ​抗藥性背景​：雖然它能抵抗葡萄球菌的β-內醯胺酶，但對​耐甲氧西林金黃色葡萄球菌 (MRSA)​ 或 ​耐甲氧西林偽中間葡萄球菌 (MRSP)​ 無效，因為這些細菌具有不同的抗藥機制（透過mecA基因改變標靶位點）。
  • ​獸醫應用限制​：由於其半衰期極短（需每6-8小時給藥一次）、口服生物利用度差，且缺乏便利的獸醫專用口服劑型，目前在獸醫學中較少使用。臨床上通常更傾向使用頭孢菌素或阿莫西林-克拉維酸鉀以提高便利性。

作用機轉

Oxacillin is a bactericidal beta-lactam antibiotic.

  • Mechanism: It covalently binds to ​Penicillin-Binding Proteins (PBPs)​ (specifically transpeptidases) located on the inner membrane of the bacterial cell wall.
  • Pathway: PBP binding → inhibition of the terminal transpeptidation step of peptidoglycan synthesis → weakened cell wall → osmotic instability → cell lysis and death.
  • Enzyme Resistance: The drug features a bulky isoxazolyl side chain that provides steric hindrance, preventing staphylococcal ​beta-lactamase (penicillinase)​ from hydrolyzing and destroying the beta-lactam ring.

安全性與警告

禁忌症

  • Known hypersensitivity to penicillins
  • Oral administration in patients with septicemia, shock, or other grave illnesses (due to delayed/diminished GI absorption)

不良反應

  • Anorexia
  • Vomiting
  • Antibiotic-associated diarrhea and superinfections
  • Hypersensitivity reactions (rash, fever, eosinophilia, anaphylaxis)
  • Neurotoxicity (ataxia, CNS effects at very high doses)
  • Elevated liver enzymes
  • Tachypnea
  • Dyspnea
  • Edema
  • Tachycardia

注意事項

Use cautiously in patients with documented hypersensitivity to other beta-lactam antibiotics (e.g., cephalosporins, carbapenems) due to potential cross-reactivity. Safe use during pregnancy is not firmly established, though it is generally considered safe (Papich Class A / FDA Category B). May cause diarrhea, candidiasis, or allergic responses in nursing offspring as it is excreted in maternal milk.

藥物交互作用

Aminoglycosides

In vitro evidence of synergism against S. aureus strains; however, mixing in the same syringe/fluid line can cause physical inactivation.

Cyclosporine

Oxacillin may reduce cyclosporine serum levels.

Probenecid

Competitively blocks the tubular secretion of oxacillin, thereby increasing serum levels and prolonging serum half-life.

Tetracyclines

Theoretical antagonism (bacteriostatic drugs may interfere with bactericidal action of penicillins); concurrent use is usually not recommended.

Warfarin

Oxacillin may cause decreased warfarin efficacy.

監測

  • Clinical efficacy (resolution of infection)
  • Signs of adverse effects (GI upset, allergic reactions)

藥物動力學

半衰期

狗20-30 minutes

吸收

Resistant to acid inactivation in the gut but only partially absorbed orally (30-35% bioavailability in humans). Food decreases both the rate and extent of absorption. Rapidly absorbed after IM administration (peak levels within 30 minutes).

分佈

Distributes to lungs, kidneys, bone, bile, pleural fluid, synovial fluid, and ascitic fluid. Volume of distribution is 0.3 L/kg in dogs. Minimal CSF penetration unless meninges are inflamed. Highly protein-bound (89-94% in humans).

代謝

Partially metabolized in the liver to both active and inactive metabolites.

排除

Rapidly excreted in the urine via both glomerular filtration and tubular secretion. A small amount is excreted in feces via biliary elimination.

過量

Acute oral overdoses are unlikely to cause significant problems other than gastrointestinal distress (vomiting, diarrhea). In humans, very high dosages of parenteral penicillins, especially in patients with compromised renal function, have induced CNS effects and neurotoxicity.

可用產品

劑型

  • Powder for oral solution
  • Powder for injection

人用標示

  • Oxacillin Sodium Powder for Oral Solution: 250 mg/5 mL (when reconstituted)
  • Oxacillin Sodium Powder for Injection: 500 mg, 1 gram, 2 grams, 10 grams

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

Store unmixed powder at room temperature (15-30°C) in tight containers. Reconstituted oral solution: refrigerate and discard after 14 days (stable for 3 days at room temperature). Reconstituted injection (167 mg/mL): stable for 3 days at room temperature or 7 days if refrigerated.

飼主須知

​重要給藥時間表​：此藥物在體內代謝非常快，必須嚴格按照處方指示（通常為每8小時一次）給藥，以維持療效。

  • ​給藥方式​：除非獸醫師另有指示，請在寵物​空腹​時給藥（飯前至少1小時或飯後2小時）。
  • ​儲存方式​：口服懸浮液請保存在​冰箱​中。配製後超過14天未用完的藥水請丟棄。
  • ​副作用​：請留意寵物是否有嘔吐、腹瀉或食慾不振的情況。如果出現這些症狀，或發現任何過敏反應的跡象（如臉部腫脹、蕁麻疹、呼吸困難），請立即聯繫您的獸醫師。

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