Oxibendazole
Oxibendazole is a **benzimidazole anthelmintic** primarily utilized in equine medicine for the eradication of various internal nematodes. * **Key Targets**: Large roundworms (*Parascaris equorum*), large strongyles (*Strongylus edentatus, S. equinus, S. vulgaris*), small strongyles, threadworms, and pinworms (*Oxyuris equi*). * **Clinical Pearl**: Benzimidazole resistance is a widespread and growing concern in equine parasitology, particularly among small strongyles (cyathostomins) and *Parascaris equorum*. Routine **Fecal Egg Count Reduction Testing (FECRT)** is highly recommended to monitor farm-specific efficacy. A reduction value of less than 90% in 5-10 horses suggests resistance on a given farm. * While primarily labeled for horses, it has historical and off-label applications in cattle, sheep, and swine.
กลไกการออกฤทธิ์: 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.
ขนาดยาตามชนิดสัตว์
- 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
ขนาดยาเป็นข้อมูลอ้างอิงทางคลินิกสำหรับสัตวแพทย์ผู้มีใบอนุญาต โปรดตรวจสอบกับฉลากล่าสุดและผู้ป่วยแต่ละรายเสมอ
วิธีการให้ยา
ข้อห้ามใช้
- Severely debilitated horses
- Horses suffering from colic
- Toxemia
- Infectious disease
อาการไม่พึงประสงค์
- Hypersensitivity reactions (secondary to antigen release by dying parasites)
- Periportal hepatitis (historically noted in dogs when combined with diethylcarbamazine)
การติดตาม
- Efficacy (via Fecal Egg Count Reduction Test - FECRT)
การได้รับยาเกินขนาด
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.
ข้อมูลอ้างอิงยาของ VetSheet มีไว้สำหรับสัตวแพทย์ผู้มีใบอนุญาตเพื่อช่วยในการตัดสินใจทางคลินิก ไม่ใช่สิ่งทดแทนการวินิจฉัยของผู้เชี่ยวชาญหรือฉลากล่าสุดของผู้ผลิต