Please check your internet connection and try again.
# Metrogyl (metronidazole)
## Overview
Metronidazole is an antibiotic and antiprotozoal agent effective against anaerobic bacteria and certain protozoa.
## Primary Indications
* **Bacterial Vaginosis:** Treatment of bacterial vaginosis.
* **Trichomoniasis:** Treatment of trichomoniasis.
* **Amebiasis:** Treatment of intestinal amebiasis and extraintestinal amebiasis.
* **Giardiasis:** Treatment of giardiasis.
* **Anaerobic Bacterial Infections:** Treatment of serious anaerobic bacterial infections, such as intra-abdominal infections, skin and soft tissue infections, gynecologic infections, bone and joint infections, CNS infections, and lower respiratory tract infections. Often used in combination with other agents.
* **Pseudomembranous Colitis:** Treatment of Clostridium difficile-associated diarrhea (CDAD).
* **Surgical Prophylaxis:** Prophylaxis against anaerobic infection in specific surgical procedures (e.g., colorectal surgery).
* **H. pylori Eradication:** Part of combination therapy for Helicobacter pylori eradication.
## Adult Dosing
* **Bacterial Vaginosis:**
* Oral: 500 mg twice daily for 7 days, OR 2 g as a single dose.
* Vaginal gel 0.75%: 5 g (one applicatorful) vaginally once daily for 5 days.
* **Trichomoniasis:**
* Oral: 2 g as a single dose, OR 250 mg three times daily for 7 days, OR 375 mg twice daily for 7 days.
* **Amebiasis:**
* Intestinal: 500-750 mg three times daily for 5-10 days.
* Extraintestinal: 500-750 mg three times daily for 10-14 days.
* Maximum dose: 4 g/day for short-term therapy.
* **Giardiasis:**
* Oral: 250 mg three times daily for 5 days, OR 375 mg twice daily for 7 days.
* **Anaerobic Bacterial Infections:**
* Oral/IV: 500 mg every 8 hours.
* IV: 15 mg/kg loading dose, followed by 7.5 mg/kg every 6-8 hours.
* Duration varies based on infection severity and response, typically 7-14 days.
* Maximum dose: 4 g/day.
* **Pseudomembranous Colitis:**
* Oral: 500 mg every 8 hours for 10-14 days. (Note: Oral vancomycin is generally preferred for severe CDAD).
* **Surgical Prophylaxis:**
* IV: 1 g as a single dose given 30-60 minutes before surgery, OR 500 mg every 8 hours starting before surgery and continuing for up to 12 hours postoperatively.
* **H. pylori Eradication:**
* Oral: 500 mg twice daily in combination with other agents (e.g., omeprazole, amoxicillin) for 10-14 days.
## Pediatric Dosing
Dosing for children is based on weight and indication. Actual doses may depend on local protocol.
* **Trichomoniasis/Giardiasis:**
* Oral: 15 mg/kg/day divided into 3 doses for 7 days (max 250 mg/dose).
* **Amebiasis:**
* Oral:
* Intestinal: 35-50 mg/kg/day divided into 3 doses for 5-10 days.
* Extraintestinal: 35-50 mg/kg/day divided into 3 doses for 10-14 days.
* Maximum dose: 750 mg/dose.
* **Anaerobic Bacterial Infections:**
* Oral/IV: 7.5 mg/kg every 8 hours.
* Maximum dose: 2 g/day (though higher doses may be used under specific circumstances).
## Dose Adjustments
* **Hepatic Impairment:** Reduce dose by 50% in severe hepatic disease. Monitor for toxicity.
* **Renal Impairment:** No dose adjustment is typically needed for hemodialysis or peritoneal dialysis.
## Contraindications
* Hypersensitivity to metronidazole or other nitroimidazole derivatives.
* Use of disulfiram within the past 2 weeks.
* Acute alcohol intoxication or consumption of alcohol during therapy and for at least 3 days after discontinuation.
## Adverse Effects
* **Common:** Nausea, vomiting, diarrhea, abdominal pain, metallic taste, headache, dizziness.
* **Serious:** Peripheral neuropathy (especially with prolonged use), seizures, encephalopathy, aseptic meningitis, Stevens-Johnson syndrome, toxic epidermal necrolysis, hepatotoxicity, pancreatitis, leukopenia, thrombocytosis.
* **Disulfiram-like reaction:** With alcohol.
* **Dark urine:** Harmless, but can be alarming.
## Key Drug Interactions
* **Alcohol:** Severe disulfiram-like reaction (flushing, nausea, vomiting, headache, tachycardia). Avoid concurrent use and for at least 3 days after stopping metronidazole.
* **Warfarin:** May increase INR. Monitor INR closely and adjust warfarin dose as needed.
* **Lithium:** May increase lithium levels. Monitor lithium levels and for signs of toxicity.
* **Phenobarbital:** May decrease metronidazole levels.
* **Disulfiram:** Risk of psychotic reactions. Avoid concurrent use.
* **Busulfan:** Metronidazole may increase busulfan toxicity.
* **Certain Antineoplastics:** Concurrent use with certain chemotherapy agents may lead to increased toxicity.
## Monitoring
* Monitor for signs and symptoms of peripheral neuropathy (numbness, tingling, pain).
* Monitor for central nervous system effects (dizziness, confusion, seizures).
* Monitor for diarrhea, especially if persistent or severe, to rule out C. difficile.
* Monitor INR if co-administered with warfarin.
* Monitor lithium levels if co-administered with lithium.
* Monitor liver function tests if clinically indicated.
## Clinical Pearls
* Administer oral metronidazole with or after food to minimize gastrointestinal upset.
* Educate patients about the disulfiram-like reaction with alcohol and advise strict avoidance.
* Advise patients about the metallic taste and dark urine, which are usually transient and harmless.
* Prolonged therapy should be reserved for specific indications due to the risk of peripheral neuropathy.
***
*Disclaimer: This information is intended for clinical use and is not a substitute for professional medical advice. Always consult current prescribing information and guidelines, and exercise clinical judgment. Dosing and recommendations may vary based on patient-specific factors and local protocols.*
