Ronidazole
**Ronidazole** is a potent **5-nitroimidazole** antibiotic and antiprotozoal agent. While structurally related to metronidazole, it exhibits superior efficacy against certain resistant protozoa. * Primarily utilized off-label in veterinary medicine for the eradication of **_Tritrichomonas foetus_** infections in cats, a notorious cause of chronic large bowel diarrhea. * Also employed in avian medicine to treat trichomoniasis (canker) in non-food birds (e.g., pigeons, finches). **Clinical Pearl**: Due to its extremely bitter taste and potential human health risks (suspected carcinogen), it must be carefully compounded into intact gelatin capsules. It is strictly prohibited for use in food-producing animals.
กลไกการออกฤทธิ์: Ronidazole is a prodrug that requires activation by protozoal organelles called **hydrogenosomes**. * Inside the hydrogenosome, the drug is reduced → forms **polar autotoxic anion radicals**. * These highly reactive radicals bind to and disrupt protozoal DNA → inhibition of nucleic acid synthesis → **cell death**. *Note*: While it shares this mechanism with metronidazole, ronidazole often retains activity against metronidazole-resistant _T. foetus_ strains, though resistance to ronidazole has been documented.
ขนาดยาตามชนิดสัตว์
- treatment of T. foetus infections · 30 mg/kg PO q24h · PO · q24h · 14 days · Likely to be most effective in resolving diarrhea and eradicating T. foetus infection. Must be given in capsule form due to bitter taste.
ขนาดยาเป็นข้อมูลอ้างอิงทางคลินิกสำหรับสัตวแพทย์ผู้มีใบอนุญาต โปรดตรวจสอบกับฉลากล่าสุดและผู้ป่วยแต่ละรายเสมอ
วิธีการให้ยา
ข้อห้ามใช้
- Hypersensitivity to ronidazole or other 5-nitroimidazoles (e.g., metronidazole)
- Food-producing animals (FDA prohibited)
- Pregnant or nursing cats (safety not established; use with extreme caution)
อาการไม่พึงประสงค์
- Neurotoxicity (lethargy, anorexia, ataxia, nystagmus, seizures, behavior changes)
- Gastrointestinal effects (anorexia, vomiting)
- Carcinogenic potential (tumors in mice and rats)
- Testicular toxicity (reported in dogs)
อันตรกิริยาระหว่างยา
- Alcohol · May induce a disulfiram-like reaction (nausea, vomiting, cramps)
- Cimetidine · May decrease the metabolism of ronidazole and increase the likelihood of dose-related side effects
- Ketoconazole · May decrease the metabolism of ronidazole and increase the likelihood of dose-related side effects
- Cyclosporine · Ronidazole may increase the serum levels of cyclosporine
- Tacrolimus · Ronidazole may increase the serum levels of tacrolimus
- Fluorouracil · Ronidazole may increase the serum levels of fluorouracil and increase risk for toxicity
- Lithium · Ronidazole may increase lithium serum levels and increase risk for lithium toxicity
- Oxytetracycline · Reportedly may antagonize the therapeutic effects of metronidazole (and presumably ronidazole)
- Phenobarbital · May increase the metabolism of ronidazole thereby decreasing blood levels
- Rifampin · May increase the metabolism of ronidazole thereby decreasing blood levels
- Phenytoin · May increase the metabolism of ronidazole thereby decreasing blood levels
- Warfarin · May prolong INR/PT; avoid concurrent use if possible or intensify monitoring
การติดตาม
- Clinical efficacy (diarrhea improvement)
- Adverse effects (neurotoxicity, vomiting, anorexia)
- PCR testing (to confirm infection; note that negative results after treatment do not conclusively prove eradication)
การได้รับยาเกินขนาด
Overdoses can cause severe **neurotoxicity**, hemorrhage, and death (as reported in society finches consuming ronidazole in drinking water). Cats receiving 50 mg/kg twice daily have a greater incidence of neurotoxicity. **Treatment**: * Discontinue further therapy immediately. * Treat supportively. * Consider administering a GABA inhibitor, such as **diazepam**, to competitively inhibit GABA receptors in the CNS and control neurological signs.
ข้อมูลอ้างอิงยาของ VetSheet มีไว้สำหรับสัตวแพทย์ผู้มีใบอนุญาตเพื่อช่วยในการตัดสินใจทางคลินิก ไม่ใช่สิ่งทดแทนการวินิจฉัยของผู้เชี่ยวชาญหรือฉลากล่าสุดของผู้ผลิต