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セフォタキシム

Cefotaxime

Cefotaxime sodium

抗生物質 - 第3世代セファロスポリンIVIMSCRegional perfusionNebulization犬猫鳥爬虫類馬

別名: Claforan · cefotaximum natricum · CTX · HR-756 · RU-24756

VetSheet 獣医チームが監修更新日 2026年4月5日エビデンスに基づく獣医学リファレンス

WHO最高位重要抗菌薬 — 慎重に使用し、不要な処方は避ける
22 mg/kg IV, IM or SC q8h for 7 days or less or 50 mg/kg IV or IM q12h for 7 days or lessIV, IM, SC· q8h or q12h· 7 days or less
— 🐕

用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。

動物種別用量

🌎 NA — North America🌍 EU — Europe

犬

適応用量経路頻度期間地域
Soft tissue infections22 mg/kg IV, IM or SC q8h for 7 days or less or 50 mg/kg IV or IM q12h for 7 days or lessIV, IM, SCq8h or q12h7 days or less🌎 NA
Orthopedic infections20-40 mg/kg IV, IM or SC q6-8h for 7 days or lessIV, IM, SCq6-8h7 days or less🌎 NA
Severe bacteremia20-80 mg/kg IV q6h or 10-50 mg/kg IV q4-6h for as long as necessaryIVq4-6hAs long as necessary🌎 NA
Susceptible infections25-50 mg/kg IV, IM or SC q8hIV, IM, SCq8h—🌎 NA
Sepsis20-80 mg/kg IV, IM q8hIV, IMq8h—🌎 NA
CNS infections (spinal cord)25 mg-50 mg/kg IV, IM q8hIV, IMq8h—🌎 NA
Acute sepsis or serious susceptible infections40-50 mg/kgIV/IM/SCq8hUntil clinical resolution🌍 EU
Susceptible infections10-20 mg/kgIV/IM/SCq12hUntil clinical resolution🌍 EU
  • Acute sepsis or serious susceptible infections: Standard recommended dose.
  • Susceptible infections: Lower dose suggested by some authors to have good clinical efficacy.

猫

適応用量経路頻度期間地域
Severe bacteremia20-80 mg/kg IV or IM q6h as long as necessaryIV, IMq6hAs long as necessary🌎 NA
Susceptible infections25-50 mg/kg IV, IM or SC q8hIV, IM, SCq8h—🌎 NA
Sepsis20-80 mg/kg IV, IM q8hIV, IMq8h—🌎 NA
CNS infections (spinal cord)25 mg-50 mg/kg IV, IM q8hIV, IMq8h—🌎 NA
To prevent bacterial colonization of pancreas in severe pancreatitis, anorexia, or SIRS50 mg/kg IM q8hIMq8h—🌎 NA
Acute sepsis or serious susceptible infections40-50 mg/kgIV/IM/SCq8hUntil clinical resolution🌍 EU
  • Acute sepsis or serious susceptible infections: Standard recommended dose.

鳥

適応用量経路頻度期間地域
Susceptible infections (most birds)50-100 mg/kg IM three times a dayIMTID—🌎 NA
Bacterial infections, bacterial hepatitis75-100 mg/kg IM or IV q4-8hIM, IVq4-8h—🌎 NA
Susceptible infections in ratites (young birds)25 mg/kg IM 3 times dailyIMTID—🌎 NA
Susceptible infections75 mg/kg IM q8hIMq8h—🌎 NA
  • Susceptible infections (most birds): May be used with aminoglycosides, but nephrotoxicity may occur. Reconstituted vial good for 13 weeks if frozen.

爬虫類

適応用量経路頻度期間地域
Susceptible infections20-40 mg/kg IM once daily for 7-14 daysIMq24h7-14 days🌎 NA
Susceptible infections in chelonians20-40 mg/kg IM q24hIMq24h—🌎 NA
Nebulized antibiotic therapy100 mg twice dailyNebulizationBID—🌎 NA

馬

適応用量経路頻度期間地域
Susceptible infections in foals40 mg/kg IV q6hIVq6h—🌎 NA
Meningitis in foals40 mg/kg IV 3-4 times a dayIV3-4 times a day—🌎 NA
Systemic therapy in foals20-30 mg/kg IV or IM q6-8hIV, IMq6-8h—🌎 NA
Regional perfusion for adjunctive treatment of septic arthritis in foals1 gram cefotaxime in 20 mL of saline. Tourniquet above and below joint. Inject antibiotic solution and leave tourniquet in place for 20 minutes.Regional perfusionOnce20 minutes🌎 NA

用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。

診察中ですか？VetSheet の AI が薬剤・用量・投与期間を構造化された診察記録に直接記入します。VetSheet の仕組みを見る

概要

セフォタキシムは、グラム陽性菌およびグラム陰性菌の両方に対して広範な抗菌スペクトルを持つ​第3世代注射用セファロスポリン系​抗生物質です。

主な臨床的特徴：

  • ​グラム陰性菌への拡張された抗菌力​：腸内細菌科（クレブシエラ、大腸菌、サルモネラ、プロテウスなど）に対して非常に有効です。
  • ​嫌気性菌への活性​：バクテロイデス・フラジリスやクロストリジウム属を含む多くの嫌気性菌に有効です。
  • ​中枢神経系への移行性​：第1世代およびほとんどの第2世代セファロスポリンとは異なり、髄膜に炎症がある場合、​脳脊髄液（CSF）​内で治療濃度に達するため、細菌性髄膜炎や脊髄感染症の治療に有用です。
  • ​投与方法​：経口ではほとんど吸収されないため、非経口（IV、IM、SC）で投与する必要があります。副作用を最小限に抑えるため、静脈内投与はゆっくり（3〜5分以上かけて）行う必要があります。

​臨床のポイント​：多くのグラム陰性好気性菌に対して優れた活性を示しますが、緑膿菌に対する有効性は変動しやすく、臨床結果は期待外れになることがよくあります。感受性試験には30マイクログラムのセフォタキシムディスクを使用する必要があります。

作用機序

Cefotaxime is a time-dependent, bactericidal antibiotic.

  • Mechanism: It binds to specific ​penicillin-binding proteins (PBPs)​ located inside the bacterial cell wall → inhibits the third and final stage of bacterial cell wall peptidoglycan synthesis → leads to cell lysis and death mediated by bacterial cell wall autolytic enzymes (autolysins).
  • Metabolism: It is partially metabolized in the liver to desacetylcefotaxime, an active metabolite that works synergistically with the parent compound to enhance antibacterial activity.

安全性・警告

禁忌

  • Patients with a documented history of hypersensitivity to cephalosporins

有害事象

  • Pain at the IM injection site
  • Thrombophlebitis (after IV administration)
  • Hypersensitivity reactions (rashes, fever, eosinophilia, anaphylaxis)
  • Antibiotic-associated diarrhea (alteration of gut flora)
  • Sterile abscesses or local tissue reactions
  • Rarely: Nephrotoxicity, neurotoxicity (at high doses), neutropenia, agranulocytosis, thrombocytopenia, hepatitis

注意事項

Use with caution in patients with documented hypersensitivity to other beta-lactam antibiotics (e.g., penicillins, carbapenems) due to potential cross-reactivity (estimated 1-15% in humans). Dosage adjustments may be necessary in patients with renal failure. May cause false-positive direct Coombs' tests, falsely elevated 17-ketosteroid urine values, and false-positive urine glucose determinations when using cupric sulfate solution tests (e.g., Clinitest).

医薬品相互作用

Aminoglycosides / Nephrotoxic drugs (e.g., amphotericin B)

Potential for additive nephrotoxicity. In vitro studies show synergistic antibacterial activity, but they must NOT be mixed in the same syringe or fluid bag.

Probenecid

Competitively blocks the renal tubular secretion of cefotaxime, significantly increasing its serum levels and prolonging its elimination half-life.

OxytetracyclineModerate

Bacteriostatic agents may antagonize the bactericidal activity of cephalosporins.

ErythromycinModerate

Bacteriostatic agents may antagonize the bactericidal activity of cephalosporins.

AminoglycosidesMinor

Synergistic antibacterial effect, but do not mix in the same syringe due to chemical incompatibility.

Amphotericin BMajor

Increased risk of nephrotoxicity.

FurosemideMajor

Loop diuretics may increase the risk of nephrotoxicity when used with cephalosporins.

監視

  • Clinical efficacy (resolution of infection signs)
  • Renal function parameters (BUN, creatinine, urinalysis) in compromised patients or those on concurrent nephrotoxic drugs

薬物動態

半減期

猫~1 hour犬45 minutes (IV), 50 minutes (IM), 103 minutes (SC)

吸収

Not appreciably absorbed after oral administration; must be given parenterally. Bioavailability is approximately 87-98% after IM injection and ~100% after SC injection.

分布

Widely distributed in body tissues including bone, prostatic fluid, aqueous humor, bile, ascitic, and pleural fluids. Enters the CSF in therapeutic levels when meninges are inflamed. Crosses the placenta (activity in amniotic fluid equals or exceeds maternal serum) and distributes into milk in low concentrations. Protein binding is 13-40% in humans. Volume of distribution at steady state in dogs is 480 mL/kg.

代謝

Partially metabolized by the liver to desacetylcefotaxime, which exhibits some antibacterial activity. This is further degraded to inactive metabolites.

消失

Primarily excreted in the urine via tubular secretion. Total body clearance is 10.5 mL/min/kg in dogs and ~3 mL/min/kg in cats.

過剰投与

Acute cephalosporin overdoses are unlikely to cause significant life-threatening problems. However, massive overdoses may exacerbate adverse effects, potentially leading to neurotoxicity (seizures, encephalopathy), nephrotoxicity, or severe gastrointestinal upset. Treatment should consist of standard supportive care and monitoring.

製品

製剤

  • Powder for injection
  • Premixed frozen injection solution

ヒト用医薬品

  • Cefotaxime Sodium Powder for Injection: 500 mg, 1 g, 2 g, & 10 g in vials, bottles, infusion bottles & ADD-Vantage system vials
  • Cefotaxime Sodium for Injection: 1 g & 2 g in infusion bottles, & premixed, frozen 50 mL

規制ステータス

European Union✗ 未承認処方箋医薬品EMA

Classified as a highest priority critically important antibiotic. Use is heavily restricted to cases where no other appropriate licensed veterinary medicine exists and culture/susceptibility testing justifies its use.

United Kingdom✗ 未承認処方箋医薬品VMD

Subject to strict antimicrobial stewardship guidelines.

規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU

保管・安定性

Sterile powder for injection should be stored at temperatures < 30°C and protected from light. Commercially available frozen injections should be stored at < -20°C. Powder or solutions may darken depending on storage conditions, which may indicate a loss in potency. Cefotaxime is unstable in solutions with a pH > 7.5 (e.g., sodium bicarbonate).

飼主向け情報

セフォタキシムは強力な注射用抗生物質であり、通常、重篤な感染症を治療するために動物病院内で投与されます。

  • ​投与方法​：胃腸管からは吸収されないため、注射（静脈内、筋肉内、または皮下）で投与する必要があります。
  • ​副作用​：筋肉内注射は痛みを伴うことがあります。注射部位に腫れ、赤み、または痛みの兆候がないか観察してください。
  • ​アレルギー​：ペットが過去にペニシリンや他のセファロスポリン系薬物に対してアレルギー反応を起こしたことがある場合は、直ちに獣医師に知らせてください。
  • ​胃腸の不調​：多くの抗生物質と同様に、腸内の正常な細菌叢を変化させる可能性があり、時折下痢を引き起こすことがあります。下痢がひどくなったり血便が出たりした場合は、獣医師に連絡してください。

VetSheet医薬品リファレンスは獣医専門家の臨床意思決定支援を目的としており、専門的判断または製造業者の最新医薬品情報の代替にはなりません。