Metrogyl%252525252520%252525252528metronidazole%252525252529

# Metrogyl (Metronidazole) ## Overview Metronidazole is a nitroimidazole antibiotic and antiprotozoal agent. It is bactericidal against most obligate anaerobes and active against several protozoa. ## Primary Indications * Anaerobic bacterial infections (intra-abdominal, gynecologic, skin/soft tissue). * *Clostridioides difficile* infection (non-severe). * Protozoal infections: Amebiasis, giardiasis, trichomoniasis. * Bacterial vaginosis. ## Adult Dosing * **Anaerobic Infections:** 500 mg IV or PO every 8 hours. Max: 4 g/day. * **C. difficile:** 500 mg PO every 8 hours for 10–14 days. * **Trichomoniasis:** 2 g PO as a single dose OR 500 mg PO twice daily for 7 days. * **Amebiasis:** 500–750 mg PO every 8 hours for 7–10 days. * **Bacterial Vaginosis:** 500 mg PO twice daily for 7 days. ## Pediatric Dosing * **Anaerobic Infections:** 30 mg/kg/day divided every 6–8 hours. Max: 4 g/day. * **Amebiasis:** 35–50 mg/kg/day divided every 8 hours for 10 days. * **Giardiasis:** 15 mg/kg/day divided every 8 hours for 5–7 days. * *Note: Dosing depends on specific institutional protocols; verify weight-based calculations carefully.* ## Dose Adjustments * **Renal Impairment:** No routine adjustment needed for CrCl >10 mL/min. In severe renal failure (CrCl <10 mL/min), consider 50% dose reduction. * **Hepatic Impairment:** In severe hepatic disease (Child-Pugh C), reduce dose by 50% due to impaired clearance. ## Contraindications * Hypersensitivity to metronidazole or other nitroimidazoles. * First trimester of pregnancy (for treatment of trichomoniasis). * Combined use with disulfiram (within 2 weeks). * Combined use with alcohol (during and for 3 days after completion). ## Adverse Effects * **Common:** Metallic taste, nausea, headache, dark-colored urine. * **Serious:** Peripheral neuropathy (prolonged use), seizures, encephalopathy, aseptic meningitis, severe neutropenia. ## Key Drug Interactions * **Alcohol:** Disulfiram-like reaction (flushing, nausea, tachycardia). * **Warfarin:** Significant increase in INR; monitor closely and preemptively reduce warfarin dose if initiating metronidazole. * **Lithium:** May increase lithium levels and toxicity. ## Monitoring * **Peripheral Neuropathy:** Monitor for numbness/tingling in extremities. * **Hematologic:** Periodic CBC if therapy exceeds 10–14 days. * **CNS:** Monitor for signs of ataxia or confusion. ## Clinical Pearls * IV to PO conversion is 1:1 due to nearly 100% bioavailability. * Metallic taste is a common side effect and may affect patient adherence. * Avoid alcohol intake strictly during therapy and for 72 hours post-treatment to avoid severe vomiting/hypotension. * Not a first-line agent for *C. difficile* unless oral vancomycin or fidaxomicin is unavailable. *** **Educational Disclaimer:** This information is for educational purposes only. Clinical practice varies by institution and region. Always verify dosages, contraindications, and drug interactions using current, peer-reviewed clinical decision support tools or local pharmacy drug databases before prescribing or administering medication.