フロルフェニコール
**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.
動物種別の用量
- Susceptible systemic (bacterial or rickettsial) infections · 22 mg/kg · IM, PO · q12h · 3-5 days · Oral dosage form not available, but solution given orally to experimental cats was well absorbed.
- Swine respiratory disease · In water at a concentration of 400 mg/gallon (100 ppm) · PO · continuous · 5 days · Use as only source of drinking water.
- Respiratory disease complex in kids · 20 mg/kg a day · IM · q24h · 2 days · Route not specified; assume IM.
- Bovine respiratory disease (BRD) · 20 mg/kg · IM · repeat in 48 hours · 2 doses · In neck muscle only. Do not exceed 10 mL per injection site.
- Bovine respiratory disease (BRD) · 40 mg/kg · SC · once · Single dose · In neck only.
- Bovine respiratory disease (BRD) · 40 mg/kg (6 mL/100 lb B.W .) · SC · once · Single dose · Do not administer more than 15 mL at each site. Neck only.
- BRD and control of BRD-associated pyrexia · 40 mg/kg florfenicol/2.2 mg/kg flunixin (6 mL/100 lb. B.W .) · SC · once · Single dose · Do not administer more than 10 mL at each site. Neck only.
投与経路
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)
薬物相互作用
- 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.
モニタリング
- 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
過量投与
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.
VetSheet の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。