頭孢替坦
頭孢替坦是一種**第二代頭孢菌素**（特指頭孢黴素類），對厭氧菌（如擬桿菌屬）和腸道革蘭氏陰性桿菌（如大腸桿菌）具有廣效抗菌作用。 其結構與藥理特性與頭孢西丁（cefoxitin）相似，但藥代動力學特性更佳，允許在小動物中延長給藥間隔。 **臨床要點**： - 頭孢替坦含有 **N-甲基硫代四唑 (NMTT) 側鏈**（類似於頭孢哌酮）。此特定結構特徵可能干擾維生素K代謝，導致低凝血酶原血症（出血傾向），若接觸酒精可能引起戒酒硫樣反應（disulfiram-like reactions）。 - 它對許多厭氧菌高度有效，常被用於治療嚴重的軟組織感染、敗血症或腹腔內感染。
作用機制: Cefotetan is a **bactericidal** time-dependent antibiotic. - It binds to specific **Penicillin-Binding Proteins (PBPs)** located inside the bacterial cell wall. - Binding → inhibition of the third and final stage of bacterial cell wall synthesis (mucopeptide/peptidoglycan cross-linking). - This leads to weakened cell walls → cell lysis and death mediated by bacterial autolysins. - As a cephamycin, it is highly resistant to degradation by many beta-lactamases produced by Gram-negative and anaerobic bacteria.
各物種劑量
- Sepsis · 30 mg/kg q5-8h IV · IV · q5-8h
- Susceptible infections · 30 mg/kg SC q12h · SC · q12h
- Soft tissue infections · 30 mg/kg SC q12h · SC · q12h · 7 days or less
- Bacteremia, sepsis · 30 mg/kg IV, SC q8h · IV, SC · q8h · as long as required
劑量為合格獸醫專業人員的臨床參考。請務必對照最新藥品仿單及個別病患確認。
給藥途徑
禁忌症
- Known hypersensitivity to cephamycins or cephalosporins
- Caution in patients with documented hypersensitivity to penicillins or other beta-lactams (cross-reactivity possible)
- Caution in patients with severe renal dysfunction (dose interval adjustment may be required)
不良反應
- Pain at IM injection site
- Thrombophlebitis (IV administration)
- Hypersensitivity reactions (rash, fever, anaphylaxis)
- Bleeding tendencies (hypoprothrombinemia due to NMTT side chain)
- Gastrointestinal flora alteration (diarrhea, superinfections)
- Rarely: nephrotoxicity, neurotoxicity, neutropenia, thrombocytopenia at high doses
藥物相互作用
- Alcohol · Potential for a disulfiram-like reaction (vomiting, etc.) due to the NMTT side chain.
- Aminoglycosides · Potential additive nephrotoxicity; do not mix together in the same syringe/fluid bag (administer separately). May have synergistic antibacterial activity.
- Nephrotoxic drugs (e.g., Amphotericin B) · Potential additive nephrotoxicity.
監測
- Clinical efficacy (resolution of infection)
- Renal function in patients with pre-existing renal disease
- Signs of bleeding or coagulopathy (due to NMTT side chain)
過量
Massive or chronic overdoses are required to cause significant adverse effects. **Seizures** are possible with extreme beta-lactam overdoses, particularly in patients with renal impairment. Treatment is supportive and symptomatic.
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。