奧苯達唑
奧苯達唑 (Oxibendazole) 是一種**苯並咪唑類驅蟲藥**，主要用於馬匹以清除多種體內線蟲。 * **主要治療目標**：大型蛔蟲 (*Parascaris equorum*)、大型圓線蟲 (*Strongylus edentatus, S. equinus, S. vulgaris*)、小型圓線蟲、蟯蟲 (*Oxyuris equi*) 等。 * **臨床要點**：苯並咪唑類藥物的抗藥性在馬匹寄生蟲學中是一個日益嚴重的問題，特別是在小型圓線蟲和蛔蟲中。強烈建議定期進行**糞便蟲卵減少試驗 (FECRT)**，以監測特定農場的藥物療效。若5-10匹馬的減少率低於90%，則表示該農場可能存在抗藥性。 * 雖然主要標示用於馬匹，但也可標示外使用於牛、羊和豬。
作用機制: Benzimidazoles exert their anthelmintic effect by selectively binding to nematode **β-tubulin**. * **Primary Mechanism**: Binds to tubulin → prevents tubulin polymerization → inhibits **microtubule formation**. This disrupts essential intracellular transport systems within the parasite. * **Secondary Mechanism**: At higher concentrations, it disrupts metabolic pathways by inhibiting key enzymes such as **fumarate reductase** and **malate dehydrogenase**, ultimately starving the parasite of energy (ATP depletion). * *Pharmacological Note*: The selective toxicity arises because benzimidazoles have a much higher affinity for nematode tubulin compared to mammalian tubulin.
各物種劑量
- Susceptible parasites · 10-20 mg/kg PO · PO · Once
- Susceptible parasites · 10-20 mg/kg PO · PO · Once
- Susceptible parasites · 10 mg/kg PO; 15 mg/kg PO for strongyloides · PO · Once · Retreat in 6-8 weeks if reinfection is likely · Horses maintained on premises where reinfection is likely to occur should be retreated in 6-8 weeks.
- Susceptible parasites · 15 mg/kg, PO · PO · Once
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
禁忌症
- Severely debilitated horses
- Horses suffering from colic
- Toxemia
- Infectious disease
不良反應
- Hypersensitivity reactions (secondary to antigen release by dying parasites)
- Periportal hepatitis (historically noted in dogs when combined with diethylcarbamazine)
監測
- Efficacy (via Fecal Egg Count Reduction Test - FECRT)
過量
Doses of 60 times those recommended elicited no adverse reactions in horses tested. It is unlikely that this compound would cause serious toxicity when given alone to horses.
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。