オキシテトラサイクリン（眼科用）
**オキシテトラサイクリン**は、テトラサイクリン系に属する広域スペクトルの静菌性抗生物質です。 * **獣医学的用途:** 獣医眼科では、猫のクラミジアおよびマイコプラズマ結膜炎の治療、ならびに原因不明の結膜炎の非特異的または対症療法として最も頻繁に使用されます。 * **製剤:** 市販の眼軟膏は、グラム陰性菌（緑膿菌など）への抗菌スペクトルを広げるために**ポリミキシンB**と組み合わされています。
作用機序: Oxytetracycline is a bacteriostatic antibiotic that inhibits bacterial protein synthesis. * It reversibly binds to the **30S ribosomal subunit** of susceptible organisms. * This binding blocks the attachment of aminoacyl-tRNA to the mRNA-ribosome complex → **inhibits the addition of amino acids to the growing peptide chain** → halts bacterial growth and replication. * The addition of Polymyxin B (in commercial ointments) disrupts the bacterial cell membrane of gram-negative bacteria, altering permeability and causing cell death.
動物種別の用量
- Chlamydial/Mycoplasma keratoconjunctivitis · Apply 4 times daily · topical ophthalmic · q6h · 3-4 weeks · Dramatic improvement should be noted in 3-4 days, but treatment should continue for 3-4 weeks for Chlamydia to break the reproductive cycle. Better treatment is oral doxycycline 25 mg PO twice daily for three weeks.
- Susceptible infections (when no other agent is suitable) · 10 mg/kg · IM/SC · q24h · Not specified · Only use in cats when no other agent is suitable.
- Susceptible infections · 10 mg/kg · IM/SC · q24h · Not specified
- Susceptible infections · 50 mg/kg loading dose, then 25 mg/kg · PO · q12h · up to 5 days · Give oral dose on an empty stomach.
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
- Known hypersensitivity to tetracyclines or polymyxin B
- Use of concentrated cattle/sheep depot formulations in small animals
- Pregnancy (last 2-3 weeks)
- Neonates (first month of life)
- Use in cats unless absolutely necessary
有害事象
- Local irritation
- Hypersensitivity reactions (rare)
- Potential for overgrowth of non-susceptible organisms (e.g., fungi) with prolonged use
- Vomiting
- Diarrhoea
- Depression
- Hepatotoxicity (rare)
- Fever
- Hypotension (following IV administration)
- Anorexia (especially in cats)
- Superinfections (with prolonged use)
- Renal tubular functional changes
- Teeth staining in developing animals
薬物相互作用
- Penicillins · Bactericidal action of penicillins may be inhibited by oxytetracycline · moderate
- Antacids (Mg, Ca, Al) · Binds tetracycline, significantly reducing its GI absorption · major
- Food or Milk products · Binds tetracycline, reducing its absorption · major
- Methoxyflurane · May increase the nephrotoxic effects · major
- Theophylline · GI effects of tetracyclines may be increased · moderate
モニタリング
- Resolution of clinical signs (conjunctival hyperemia, chemosis, ocular discharge)
- Signs of local irritation or hypersensitivity
- Renal function (BUN, Creatinine, Urinalysis)
- Hydration status
- Gastrointestinal signs
過量投与
Topical overdose is highly unlikely to cause systemic toxicity. If severe local irritation occurs, flush the eye with sterile saline and discontinue use.
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。