ポリミキシンB
抗生物質 - ポリペプチド系Critically Important
**ポリミキシンB**は、主に**グラム陰性菌**（特に緑膿菌）に対して有効なポリペプチド系抗生物質です。グラム陽性菌は通常耐性を示します。 > **臨床上の警告：** 腎毒性が非常に高いため全身投与には適さず、局所（皮膚、眼、耳）への使用に限定されます。強塩基性であるため、消化管からは吸収されません。
作用機序: Acts as a **cationic surface-acting agent** → binds to the bacterial cell membrane → causes concentration-dependent disruption of the outer membrane of Gram-negative bacteria → leakage of intracellular contents and cell death.
動物種別の用量
Dogs
- External pseudomonal infections (e.g., keratoconjunctivitis, otitis externa) · Apply topically as directed by specific product formulation · topical · As directed · Until clinical resolution · Do not use if tympanum is ruptured.
Cats
- External pseudomonal infections (e.g., keratoconjunctivitis, otitis externa) · Apply topically as directed by specific product formulation · topical · As directed · Until clinical resolution · Do not use if tympanum is ruptured.
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
TopicalOticOphthalmic
禁忌
- Ruptured tympanic membrane (tympanum)
- Systemic administration
有害事象
- Nephrotoxicity (if absorbed systemically)
- Ototoxicity (potential, especially if tympanic membrane is ruptured)
- Local irritation
薬物相互作用
- Other antibacterial agents · Acts synergistically by disrupting the outer and cytoplasmic membranes, improving penetration of other agents into bacterial cells. · moderate
- Chlorhexidine · Cationic detergents potentiate the antibacterial effects of polymyxin B against Pseudomonas aeruginosa. · moderate
- EDTA · Chelating agents potentiate the antibacterial effects of polymyxin B against Pseudomonas aeruginosa. · moderate
モニタリング
- Resolution of clinical signs (ear, eye, or skin infection)
- Tympanic membrane integrity (must be verified before otic use)
過量投与
Systemic absorption (e.g., from ingestion of large amounts or application to extensive deep wounds) can lead to severe **nephrotoxicity** and **neurotoxicity/ototoxicity**. Treatment is supportive.
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。