多黏菌素 B
抗生素 - 多肽類Critically Important
**多黏菌素 B (Polymyxin B)** 是一種多肽類抗生素，主要對**革蘭氏陰性菌**（特別是綠膿桿菌）有效。革蘭氏陽性菌通常具有抗藥性。 > **臨床警告：** 由於具有強烈的腎毒性，本藥物不適合全身性給藥，僅限於局部皮膚、眼科及耳科使用。由於其強鹼性特質，口服不會從胃腸道吸收。
作用機制: 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.
各物種劑量
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.
劑量為合格獸醫專業人員的臨床參考。請務必對照最新藥品仿單及個別病患確認。
給藥途徑
TopicalOticOphthalmic
禁忌症
- Ruptured tympanic membrane (tympanum)
- Systemic administration
不良反應
- Nephrotoxicity (if absorbed systemically)
- Ototoxicity (potential, especially if tympanic membrane is ruptured)
- Local irritation
藥物相互作用
- 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
監測
- Resolution of clinical signs (ear, eye, or skin infection)
- Tympanic membrane integrity (must be verified before otic use)
過量
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 藥物參考供持牌獸醫專業人員作臨床決策輔助之用,不能取代專業判斷或廠方最新藥品說明書。