エンロフロキサシン
Enrofloxacin
1-cyclopropyl-7-(4-ethyl-1-piperazinyl)-6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid
別名: Baytril · Enrocare · Enrox · Xeden · Zobuxa · Bay-Vp-2674 · Enrofloxacine · Enrofloxacino · Enrofloxacinum
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
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 infections | 5-20 mg/kg per day PO | PO | q24h or divided q12h | At least 2-3 days beyond cessation of clinical signs, max 30 days | 🌎 NA |
| Sepsis | 5-20 mg/kg IV | IV | q12h | — | 🌎 NA |
| Skin, urinary infections | 2.5-5 mg/kg PO | PO | q12h | 7-14 days | 🌎 NA |
| Deep pyodermas, complicated urinary infections | 5 mg/kg PO | PO | q24h | 7-14 days (up to 10-12 weeks for deep pyoderma) | 🌎 NA |
| Lower respiratory tract infections | 5-10 mg/kg PO | PO | q24h | 7-84 days | 🌎 NA |
| Prostate infections | 5 mg/kg PO | PO | q12h | 7-14 days | 🌎 NA |
| Histiocytic ulcerative colitis | 5 mg/kg PO | PO | q12h | 21-90 days | 🌎 NA |
| Histiocytic ulcerative colitis | 5-10 mg/kg PO | PO | q24h | At least 4-6 weeks | 🌎 NA |
| Hemotropic mycoplasmosis | 5 mg/kg PO, IM | PO, IM | q12h | 7-14 days | 🌎 NA |
| Systemic orthopedic infections | 5-11 mg/kg PO, IV, IM, SC | PO, IV, IM, SC | q12h | 10 days | 🌎 NA |
| Pseudomonas infections in soft tissues | 11-20 mg/kg PO, IM, SC | PO, IM, SC | q12h | 7 days minimum | 🌎 NA |
| Bacteremia, sepsis | 11 mg/kg PO, IV, IM, SC | PO, IV, IM, SC | q12h | As long as necessary | 🌎 NA |
| Susceptible infections | 5 mg/kg | SC | q24h | Not specified | 🌍 EU |
| Prostatitis or specific sites | 10 mg/kg | SC | q24h | Not specified | 🌍 EU |
- Susceptible infections: Pulse dosing regimens may be effective.
- Prostatitis or specific sites: Even higher doses may be necessary for certain isolates of Pseudomonas aeruginosa. Contact manufacturer to discuss.
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Susceptible infections | 5 mg/kg per day PO | PO | q24h or divided q12h | At least 2-3 days beyond cessation of clinical signs, max 30 days | 🌎 NA |
| Hemoplasmosis | 5-10 mg/kg PO | PO | q24h | 14 days | 🌎 NA |
| Susceptible infections | 5 mg/kg | SC | q24h | Not specified | 🌍 EU |
| Susceptible infections | 2.5 mg/kg | PO | q12h | Not specified | 🌍 EU |
| Susceptible infections | 5 mg/kg | PO | q24h | Not specified | 🌍 EU |
- Susceptible infections: Do not exceed 5 mg/kg/day due to risk of blindness.
- Susceptible infections: Do not exceed 5 mg/kg/day due to risk of irreversible retinal blindness.
- Susceptible infections: Do not exceed 5 mg/kg/day total.
- Susceptible infections: Do not exceed 5 mg/kg/day total.
小型哺乳類
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Pasteurella upper respiratory infections in rabbits | 15-20 mg/kg PO | PO | q12h | Minimum 14 days to several months | 🌎 NA |
| Pasteurella in rabbits | 5 mg/kg PO, SC, IM or IV | PO, SC, IM, IV | q12h | 14 days | 🌎 NA |
| Susceptible infections in hedgehogs | 5-10 mg/kg PO or SC | PO, SC | q12h | — | 🌎 NA |
| Susceptible infections in chinchillas | 5-10 mg/kg PO, IM | PO, IM | q12h | — | 🌎 NA |
| Mycoplasmal pneumonia in mice and rats | 10 mg/kg PO | PO | q12h | — | 🌎 NA |
| Susceptible infections in Chinchillas, Gerbils, Guinea Pigs, Hamsters, Mice, Rats | 5-10 mg/kg PO or IM q12h or 5-20 mg/kg PO or SC q24h | PO, IM, SC | q12h or q24h | — | 🌎 NA |
| Susceptible infections in Chinchillas, Gerbils, Guinea Pigs, Hamsters, Mice, Rats (Drinking water) | 50-200 mg/liter | PO | Continuous | 14 days | 🌎 NA |
| Chronic respiratory disease in rats | 10-25 mg/kg PO | PO | q12h | — | 🌎 NA |
- Pasteurella upper respiratory infections in rabbits: First dose may be SC, do NOT give subsequent doses SC.
- Pasteurella in rabbits: If giving SC, dilute or skin may slough.
- Mycoplasmal pneumonia in mice and rats: Given with doxycycline.
- Susceptible infections in Chinchillas, Gerbils, Guinea Pigs, Hamsters, Mice, Rats: Do not use in young animals.
- Chronic respiratory disease in rats: If using theophylline concurrently, reduce theophylline dose by 30%.
フェレット
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Susceptible infections | 10-20 mg/kg PO, IM, SC | PO, IM, SC | q12h | — | 🌎 NA |
鳥
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Empirical treatment in stable, immunocompetent Psittacines | 20 mg/kg PO | PO | q24h | — | 🌎 NA |
| Debilitated immunocompetent Psittacines | 15-20 mg/kg SC in fluid pocket | SC | q24h | — | 🌎 NA |
| Debilitated, immunocompromised Psittacines | 15-20 mg/kg SC in fluid pocket | SC | q12h | — | 🌎 NA |
| Susceptible infections in Ratites | 1.5-2.5 mg/kg PO or SC | PO, SC | q12h | — | 🌎 NA |
| Susceptible infections in Ratites (Drinking water) | 10% solution, 10 mg/kg | PO | Daily | 3 days | 🌎 NA |
| Susceptible infections in Ratites (IM) | 5 mg/kg IM | IM | q12h | 2 days | 🌎 NA |
- Empirical treatment in stable, immunocompetent Psittacines: Given with amoxicillin/clavulanate.
- Susceptible infections in Ratites (IM): IM injections cause severe muscle necrosis.
爬虫類
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Susceptible respiratory infections for most species | 5 mg/kg IM | IM | Every 5 days | 25 days | 🌎 NA |
| Chronic respiratory infections in tortoises | 15 mg/kg IM | IM | Every 72 hours | 5-7 treatments | 🌎 NA |
馬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Susceptible infections | 5 mg/kg IV q24h; 5-7.5 mg/kg PO q24h | IV, PO | q24h | — | 🌎 NA |
| Susceptible respiratory infections | 7.5 mg/kg PO or IV | PO, IV | q24h | — | 🌎 NA |
| Susceptible infections (using compounded gel) | 7.5 mg/kg PO | PO | q24h | — | 🌎 NA |
- Susceptible infections: Use in horses is controversial. Only use in adults when other antibiotics are inappropriate.
- Susceptible infections (using compounded gel): Fast for 11-14 hours prior and 1-2 hours after dosing. Rinse mouth with water after dosing.
牛
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Bovine respiratory disease | 2.5-5 mg/kg SC once daily for 3-5 days or 7.5-12.5 mg/kg SC once | SC | q24h or single dose | 3-5 days or once | 🌎 NA |
- Bovine respiratory disease: Not for dairy cattle or veal calves. 28-day slaughter withdrawal. Extra-label use prohibited.
羊
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Susceptible infections in alpacas (Camelids) | 5 mg/kg SC or 10 mg/kg PO | SC, PO | q24h | — | 🌎 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。
概要
エンロフロキサシンは、獣医用に特別に開発された広域スペクトルの濃度依存性フルオロキノロン系抗菌薬です。
- 抗菌スペクトル: 多くのグラム陰性桿菌（緑膿菌、大腸菌、クレブシエラ、サルモネラなど）およびグラム陽性球菌（メチシリン耐性株を含むブドウ球菌など）に対して高い有効性を示します。
- 制限: 嫌気性菌に対する活性は弱く、レンサ球菌に対する有効性は変動します。
- 臨床的特徴: 脂溶性が高く、前立腺、骨、脳脊髄液、細胞内（マクロファージ内など）などの到達困難な部位にも優れた組織移行性を示し、深部感染や細胞内感染に非常に有効です。
作用機序
Enrofloxacin exerts its rapid bactericidal effect by targeting key bacterial enzymes involved in DNA replication and transcription:
- Inhibits DNA gyrase (Topoisomerase II) → prevents the negative supercoiling of bacterial DNA required for replication.
- Inhibits Topoisomerase IV → interferes with the separation of interlinked replicated DNA molecules.
Result: Disruption of DNA synthesis → double-strand DNA breaks → rapid bacterial cell death within 20-30 minutes of exposure.
Pharmacodynamic Pearl: Enrofloxacin exhibits a significant post-antibiotic effect (PAE) for both Gram-negative and Gram-positive bacteria, meaning bacterial growth continues to be suppressed even after drug concentrations fall below the Minimum Inhibitory Concentration (MIC).
安全性・警告
禁忌
- Small and medium breed dogs 2 to 8 months of age (risk of cartilage damage)
- Large and giant breed dogs during their rapid-growth phase (may extend past 8 months)
- Patients hypersensitive to quinolones
- Foals (highly susceptible to arthropathic effects)
- Food-producing animals (extra-label use is strictly prohibited by the FDA)
- Dairy cattle or veal calves
- Growing dogs (<1 year of age; large-breed dogs <18 months of age)
- Cats <8 weeks of age
- Animals with known seizure disorders (relative contraindication)
有害事象
- Gastrointestinal distress (vomiting, anorexia, diarrhea)
- CNS stimulation (seizures, depression, lethargy, nervousness, ataxia)
- Cartilage abnormalities in young, growing animals
- Ocular toxicity/blindness in cats (at doses >5 mg/kg/day)
- Crystalluria (especially in dehydrated patients)
- Hypersensitivity reactions
- Elevated hepatic enzymes
- Tissue damage or pain at injection site (especially SC)
- Irreversible retinal blindness (cats)
- Cartilage abnormalities (growing dogs)
- Gastrointestinal upset (vomiting, diarrhea, anorexia)
- CNS toxicity / seizures (especially at high doses or with NSAIDs)
注意事項
Use with caution in patients with seizure disorders due to potential CNS stimulation.
Ensure patients remain well-hydrated to prevent crystalluria.
Patients with severe renal or hepatic impairment may require dosage adjustments to prevent drug accumulation.
Intravenous Administration Risks: Rapid or undiluted IV administration in dogs increases the risk of cardiac arrhythmias, hypotension, vomiting, and mast cell degranulation. Do not mix injectable enrofloxacin with any IV solution containing magnesium (e.g., Normosol-R, Plasmalyte) as micro-precipitants can lodge in the lungs, causing morbidity or mortality.
Feline Precautions: Doses exceeding 5 mg/kg/day in cats are associated with severe ocular toxicity, including irreversible retinal degeneration and blindness.
医薬品相互作用
Cations bind to enrofloxacin and prevent its absorption; separate doses by at least 2 hours.
Synergism may occur, though unpredictable against some bacteria like Pseudomonas aeruginosa.
May exacerbate nephrotoxicity and reduce the metabolism of systemic cyclosporine.
Increases the AUC and elimination half-life of both enrofloxacin and flunixin in dogs.
Severe hypoglycemia is possible.
Decreased enrofloxacin absorption; separate doses by at least 2 hours.
Increased methotrexate levels possible, resulting in toxicity.
May antagonize the antimicrobial activity of fluoroquinolones; concomitant use is not recommended.
May alter phenytoin blood levels.
Blocks tubular secretion of ciprofloxacin (active metabolite), increasing its blood level and half-life.
Increased risk for cardiotoxicity.
May inhibit absorption of enrofloxacin; separate doses by at least 2 hours.
May increase theophylline blood levels (by about 30-50% in dogs).
Potential for increased warfarin effects.
Binds fluoroquinolones, preventing GI absorption
Inhibits absorption (separate dosing by at least 2 hours)
May reduce the clearance of fluoroquinolones
Decreases metabolism and increases nephrotoxicity of ciclosporin
Decreases metabolism and increases nephrotoxicity of tacrolimus
Potentiates CNS adverse effects (seizure risk)
May increase the action of anticoagulants
監視
- Clinical efficacy (resolution of infection)
- Adverse effects (GI upset, CNS signs)
- In cats: Monitor closely for mydriasis (dilated pupils) and/or retinal changes/vision loss
- Vision and pupillary light reflexes in cats
- Neurological status, especially in patients with a history of seizures
- Joint pain or lameness in young animals (if inadvertently administered)
薬物動態
半減期
吸収
Well absorbed after oral administration in most species. In dogs, oral bioavailability is ~80% (twice that of ciprofloxacin). Horses: 60-80%. Sheep: 65-75%. Peak levels (Cmax) occur within 1 hour of dosing. Food may delay the rate but not the extent of absorption.
分布
Widely distributed throughout the body. Volume of distribution (Vd) in dogs is ~3-4 L/kg. Only ~27% bound to canine plasma proteins. Concentrates in macrophages, bile, kidney, liver, lungs, and reproductive system (prostate). Therapeutic levels attained in bone, synovial fluid, skin, muscle, aqueous humor, and pleural fluid. Low concentrations in CSF (6-10% of serum levels).
代謝
Metabolized to various metabolites. Approximately 10-40% of circulating enrofloxacin is metabolized to the active compound ciprofloxacin in most species (dogs, cats, adult horses, cattle, turtles, snakes). Foals, pigs, and some lizards do not convert much enrofloxacin to ciprofloxacin.
消失
Eliminated via both renal (tubular secretion and glomerular filtration) and non-renal (feces/hepatic) mechanisms. Approximately 15-50% is eliminated unchanged in the urine.
過剰投与
Acute overdoses in dogs typically result in gastrointestinal signs (anorexia, vomiting). Dogs receiving 10X the labeled dose for 14 days developed only vomiting and anorexia. However, extreme overdoses (25X the labeled rate for 11 days) resulted in death.
In cats, overdoses can be severe and irreversible. Doses of 20 mg/kg or more can cause retinopathy, blindness, and seizures.
Common signs of toxicity reported to poison control include vomiting, lethargy, seizures, anorexia, depression, and diarrhea in dogs; and seizures and recumbency in cats.
製品
製剤
- Tablets (film-coated)
- Oral taste tablets
- Injectable solution (2.27% for small animals, 10% for large animals)
- Compounded oral suspension or gel
- Injectable: 25 mg/ml, 50 mg/ml
- Oral tablets: 15 mg, 50 mg, 100 mg, 150 mg, 200 mg, 250 mg
- Oral solution: 25 mg/ml
動物用医薬品
- Enrofloxacin Tablets (Film-Coated) & Oral Taste Tablets: 22.7 mg, 68 mg, 136 mg (Baytril)
- Enrofloxacin Injection: 22.7 mg/mL (2.27%) in 20 mL vials (Baytril)
- Enrofloxacin Injection: 100 mg/mL (10%) in 100 mL and 250 mL bottles (Baytril 100)
- Enrocare
- Enrotron
- Enroxil
- Fenoflox
- Floxabactin
- Powerflox
- Quinoflox
- Xeden
- Zobuxa
ヒト用医薬品
- None
規制ステータス
POM-V. Subject to strict antimicrobial stewardship guidelines.
POM-V
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Tablets should be stored in tight containers at temperatures less than 30°C and protected from strong UV light. The 2.27% injection should be protected from light and not frozen. The 10% cattle injection should be protected from sunlight, not refrigerated or frozen, and stored below 40°C (104°F). If exposed to cold, precipitation may occur; warm and shake to redissolve.
飼主向け情報
猫の飼い主様への重要な注意: 獣医師の指示した用量を絶対に超えないでください。猫に高用量を投与すると、永久的な失明を引き起こす可能性があります。猫の瞳孔が異常に大きい、または目が見えにくそうにしていることに気づいた場合は、直ちに投与を中止し、獣医師に連絡してください。
- 投与方法: 可能であれば空腹時に投与してください。ただし、嘔吐したり気分が悪そうにしている場合は、少量の食事と一緒に与えても構いません。
- 錠剤の取り扱い: フィルムコーティング錠は砕かないでください。中の薬は非常に苦いため、砕くとペットが拒否したり、過剰に唾液を流したりする原因になります。
- 水分補給: 尿中の結晶化を防ぐため、投薬中は常に新鮮な水を十分に飲めるようにしてください。
- 幼若動物: 正常な関節や軟骨の発達を妨げる可能性があるため、成長期の幼犬や幼猫への使用は通常推奨されません。
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。