ダノフロキサシン
ダノフロキサシンは、主に肉牛のウシ呼吸器病（BRD）の治療に使用される獣医専用の注射用**フルオロキノロン系抗生物質**です。*Mannheimia haemolytica* や *Pasteurella multocida* などの主要な呼吸器病原体に対して、濃度依存性の殺菌活性を示します。 **臨床のポイント:** * 他のフルオロキノロン系と同様に、組織移行性が高く、特に肺組織への移行性に優れているため、呼吸器感染症に非常に有効です。 * 分布容積が大きく、滲出液や漏出液によく濃縮されます。 * **規制上の警告:** 米国FDAは、食用水動物へのフルオロキノロン系薬剤の適応外使用を厳しく禁じています。
作用機序: Fluoroquinolones are bactericidal antibiotics that act by inhibiting bacterial DNA replication and transcription. * They enter the bacterium and inhibit **DNA gyrase** (topoisomerase II) and **topoisomerase IV**. * Inhibition of **DNA gyrase** → prevents DNA supercoiling → halts DNA replication. * Inhibition of **topoisomerase IV** → interferes with the separation of interlinked replicated DNA molecules. * This dual action leads to rapid bacterial cell death. The bactericidal activity is **concentration-dependent** rather than time-dependent.
動物種別の用量
- Ophthalmic infections · 1 drop to affected eye · topical · q6h · As directed by veterinarian · Intensive therapy: q30-120min for short-term use (1-2 days).
- Bovine Respiratory Disease (BRD) · 6 mg/kg (1.5 mL per 100 lb body weight) SC · SC · Repeat once in approximately 48 hours · 2 doses total · Administered dosage volume should not exceed 15 mL per injection site.
- Ophthalmic infections · 1 drop to affected eye · topical · q6h · As directed by veterinarian · Intensive therapy: q30-120min for short-term use (1-2 days).
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
禁忌
- Extra-label use in food-producing animals (FDA prohibited)
- Lactating dairy cattle (where milk is for human consumption)
- Veal calves
- Animals with known or suspected CNS disorders (relative contraindication)
- Known hypersensitivity to ofloxacin or other fluoroquinolones
有害事象
- Hypersensitivity reactions (uncommon)
- Lameness or arthropathies (especially in young animals/calves)
- Local tissue reaction at the subcutaneous injection site (may result in trim loss)
- Mild, transient ocular irritation or stinging upon application (general class effect)
- Conjunctival hyperemia (rare)
薬物相互作用
- Theophylline (aminophylline) · Potential increase in serum concentrations of theophylline; increased monitoring of theophylline concentrations is recommended
モニタリング
- Clinical efficacy
- Injection site reactions
- Signs of lameness or CNS stimulation
- Clinical response to therapy (resolution of ocular discharge, inflammation, or ulceration)
- Culture and sensitivity testing prior to and during prolonged treatment if no improvement
過量投与
Limited information is available for cattle. High dosages (18-60 mg/kg for 3-6 days) in feeder calves can cause **arthropathies/lameness** (consistent with other fluoroquinolones), **CNS stimulation** (ataxia, nystagmus, tremors), inappetence, recumbency, depression, and exophthalmos. Some calves receiving 18 mg/kg twice 48 hours apart developed nasal pad erythema. In adult dogs, 2.4 mg/kg/day PO for 90 days resulted in no observable adverse effects.
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。