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フロルフェニコール

Florfenicol

Fluorinated analog of thiamphenicol (Sch-25298)

抗生物質 - アンフェニコール系IMSCPOTopical犬猫牛豚羊ヤギ

別名: Nuflor Gold · Resflor Gold · Aquaflor · Osurnia · Sch-25298 · Florfenicolum

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高位重要抗菌薬 — 責任ある使用を推奨
20 mg/kgIM· q8h· 3-5 days
— 🐕

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
Susceptible systemic (bacterial or rickettsial) infections20 mg/kgIMq8h3-5 days🌎 NA
Otitis externa (associated with Staphylococcus pseudintermedius and Malassezia pachydermatis)1 tube (1.2 g) per infected eartopicalRepeat once after 7 days2 doses total🌍 EU
  • Susceptible systemic (bacterial or rickettsial) infections: Used when myelotoxic potential of chloramphenicol is to be avoided.
  • Otitis externa (associated with Staphylococcus pseudintermedius and Malassezia pachydermatis): Clean ear before first dose. Do not clean before second dose or for 14 days after.

猫

適応用量経路頻度期間地域
Susceptible systemic (bacterial or rickettsial) infections22 mg/kgIM, POq12h3-5 days🌎 NA
  • Susceptible systemic (bacterial or rickettsial) infections: Oral dosage form not available, but solution given orally to experimental cats was well absorbed.

牛

適応用量経路頻度期間地域
Bovine respiratory disease (BRD)20 mg/kgIMrepeat in 48 hours2 doses🌎 NA
Bovine respiratory disease (BRD)40 mg/kgSConceSingle dose🌎 NA
Bovine respiratory disease (BRD)40 mg/kg (6 mL/100 lb B.W .)SConceSingle dose🌎 NA
BRD and control of BRD-associated pyrexia40 mg/kg florfenicol/2.2 mg/kg flunixin (6 mL/100 lb. B.W .)SConceSingle dose🌎 NA
  • Bovine respiratory disease (BRD): In neck muscle only. Do not exceed 10 mL per injection site.
  • Bovine respiratory disease (BRD): In neck only.
  • Bovine respiratory disease (BRD): Do not administer more than 15 mL at each site. Neck only.
  • BRD and control of BRD-associated pyrexia: Do not administer more than 10 mL at each site. Neck only.

豚

適応用量経路頻度期間地域
Swine respiratory diseaseIn water at a concentration of 400 mg/gallon (100 ppm)POcontinuous5 days🌎 NA
  • Swine respiratory disease: Use as only source of drinking water.

羊

適応用量経路頻度期間地域
Respiratory disease complex in kids20 mg/kg a dayIMq24h2 days🌎 NA
  • Respiratory disease complex in kids: Route not specified; assume IM.

ヤギ

適応用量経路頻度期間地域
Respiratory disease complex in kids20 mg/kg a dayIMq24h2 days🌎 NA
  • Respiratory disease complex in kids: Route not specified; assume IM.

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

​フロルフェニコール​は、クロラムフェニコールおよびチアムフェニコールに構造的に関連する合成の​広域スペクトル静菌性抗生物質​です。

​主な臨床的特徴：​

  • ​安全性プロファイル：​ クロラムフェニコールとは異なり、フロルフェニコールにはヒトにおいて特異的で不可逆的な再生不良性貧血を引き起こすパラニトロ基がありません。これにより、食用動物や薬剤を取り扱う人間にとって安全性が大幅に向上しています。
  • ​獣医学的承認：​ 主に牛（牛呼吸器病）、豚、および水産養殖（魚類）での使用がFDAによって承認されています。
  • ​適応外使用：​ 特にクロラムフェニコールの骨髄毒性を避ける必要がある場合、小動物（犬や猫）およびエキゾチックアニマルの感受性全身性細菌感染症またはリケッチア感染症に対して適応外で使用されることがよくあります。
  • ​抗菌スペクトル：​ Mannheimia haemolytica、Pasteurella multocida、Histophilus somni、Mycoplasma bovisのほか、幅広いグラム陽性およびグラム陰性菌に対して高い有効性を示します。

作用機序

Florfenicol is a time-dependent, primarily bacteriostatic antibiotic (though it can be bactericidal against certain highly susceptible respiratory pathogens).

  • ​Mechanism:​ It readily penetrates bacterial cells and binds reversibly to the 50S ribosomal subunit.
  • ​Pathway:​ Binding to the 50S subunit → inhibits the enzyme peptidyl transferase → prevents peptide bond formation → inhibits bacterial protein synthesis.
  • ​Resistance:​ Because it is fluorinated at the 3' position, it is resistant to inactivation by chloramphenicol acetyltransferase, an enzyme that confers resistance to chloramphenicol in many bacteria.

安全性・警告

禁忌

  • Intravenous (IV) administration
  • Veal calves or preruminating calves
  • Cattle or swine of breeding age (effects on reproduction unknown)
  • Female dairy cattle 20 months of age or older
  • Tympanic membrane rupture (perforated eardrum)
  • Hypersensitivity to florfenicol, terbinafine, or betamethasone
  • Dogs with generalized demodicosis (due to corticosteroid component)

有害事象

  • Cattle: Anorexia, decreased water consumption, diarrhea
  • Cattle: Injection site reactions (may result in trim loss)
  • Cattle: Anaphylaxis and collapse (rare)
  • Small Animals: Pain on IM injection
  • Small Animals: Gastrointestinal effects, including severe diarrhea
  • Mild application site erythema
  • Head shaking
  • Transient hearing loss (rare)
  • Altered hearing or deafness in older dogs (rare)

注意事項

​Important Administration Warning:​ Do NOT administer intravenously (IV).

  • ​Injection Site:​ In cattle, injections should be given only in the neck muscle to minimize trim loss and severe tissue reactions.
  • ​Volume Limits:​ Do not exceed 10 mL (or 15 mL for Nuflor Gold) per injection site in cattle.
  • ​Residue Warnings:​ Strict adherence to slaughter withdrawal times is legally required for food-producing animals. Do not use in female dairy cattle ≥20 months of age or in veal calves.
  • ​Reproductive Safety:​ Safety in breeding, pregnant, or lactating animals has not been established.

医薬品相互作用

Penicillins

May antagonize the bactericidal activity of penicillins (theoretical, though often used together clinically).

Aminoglycosides

May antagonize the bactericidal activity of aminoglycosides.

Macrolides (e.g., erythromycin, tylosin)

May potentially antagonize activity due to competition for binding at the 50S ribosomal subunit.

Lincosamides (e.g., clindamycin, lincomycin)

May potentially antagonize activity due to competition for binding at the 50S ribosomal subunit.

監視

  • Clinical efficacy (resolution of infection/fever)
  • Injection site reactions (swelling, pain, tissue necrosis)
  • Gastrointestinal signs (appetite, stool consistency)
  • Resolution of clinical signs of otitis externa
  • Cytology to confirm clearance of bacteria and yeast
  • Integrity of the tympanic membrane

薬物動態

半減期

猫< 5 hours犬< 5 hours (1.25 hours PO)

吸収

Cattle: ~79% bioavailable after IM injection. Dogs: Poorly absorbed after SC injection; good bioavailability (95%) after PO administration. Cats: High absorption of a 100 mg/mL solution when given IM or PO.

分布

Well distributed throughout the body, achieving therapeutic levels in the CSF. Cattle: Volume of distribution is ~0.7 L/kg; ~13% bound to serum proteins.

代謝

Primarily hepatic metabolism (inferred from amphenicol class).

消失

Dogs: Total body clearance is ~1 L/kg/hr after IV administration; eliminated rapidly after PO administration.

過剰投与

In toxicology studies, feeder calves injected with up to 10X the recommended dosage exhibited transient adverse effects (anorexia, decreased water consumption, diarrhea) and increased serum enzymes. Long-term (43 day) standard dosage studies showed a transient decrease in feed consumption, but no long-term negative effects were noted. Treatment of acute overdose should be supportive and symptomatic.

製品

製剤

  • Injectable solution
  • Concentrate solution (water additive)
  • Feed additive
  • Topical ear gel (10 mg florfenicol, 10 mg terbinafine, 1 mg betamethasone acetate per 1.2 g dose)

動物用医薬品

  • Florfenicol Injection: 300 mg/mL (NuFlor, Nuflor Gold)
  • Florfenicol 2.3% (23 mg/mL) Concentrate Solution (NuFlor Concentrate Solution)
  • Florfenicol 300 mg/mL with Flunixin 16.5 mg/mL Injection (Resflor Gold)
  • Florfenicol feed additives (Aquaflor for fish, and swine feed formulations)
  • Osurnia ear gel (10 mg florfenicol, 10 mg terbinafine, 1 mg betamethasone acetate per tube)

規制ステータス

European Union✓ 承認済み処方箋医薬品EMA
🐕 Dogs

POM-V

United Kingdom✓ 承認済み処方箋医薬品VMD
🐕 Dogs

POM-V

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

保管・安定性

Florfenicol injection (Nuflor, Nuflor Gold) should be stored between 2°-30°C (36°-86°F). Use within 28 days of first use. The oral solution (swine) should be stored between 2°-26°C (36°-77°F). Resflor Gold should not be stored above 30°C (86°F), used within 28 days, and the vial should not be punctured more than 10 times.

飼主向け情報

小動物（犬・猫）の飼い主様へ

  • ​投与について：​ この薬を口から与える場合（液剤の適応外使用）、苦味を感じることがあります。ペットが全量をしっかり飲み込んだことを確認してください。
  • ​副作用：​ 胃腸の不調、特に重度の下痢や食欲不振に注意してください。これらの症状が見られた場合は、獣医師にご相談ください。
  • ​注射：​ 動物病院で注射を受けた場合、注射部位が一時的に痛んだり腫れたりすることがあります。

産業動物（牛・豚）の飼い主様へ

  • ​厳格な休薬期間：​
    • ​牛：​ 筋肉内注射（IM）の場合は投与後28日、皮下注射（SC）の場合は38日（Nuflor Goldは44日）。
    • ​豚：​ 16日（飲水投与）。
  • ​使用制限：​ 20ヶ月齢以上の搾乳牛には絶対に使用しないでください。仔牛肉として加工される子牛には使用しないでください。
  • ​注射方法：​ 枝肉の廃棄ロスを防ぐため、注射は必ず「頸部」にのみ行ってください。1箇所の注射部位につき、推奨される最大量を超えないようにしてください。

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