Please check your internet connection and try again.
# Metrogyl (metronidazole)
## Overview
Metronidazole is an antibiotic and antiprotozoal agent effective against anaerobic bacteria and certain parasites.
## Primary Indications
* **Bacterial vaginosis:** Bacterial infections of the vagina.
* **Trichomoniasis:** Sexually transmitted parasitic infection.
* **Amebiasis:** Infection caused by Entamoeba histolytica.
* **Giardiasis:** Intestinal infection caused by Giardia lamblia.
* **Anaerobic bacterial infections:** Intra-abdominal infections, skin and soft tissue infections, gynecologic infections, bone and joint infections, CNS infections, lower respiratory tract infections, and endocarditis.
* **Pseudomembranous colitis** (Clostridium difficile infection): Adjunct or alternative therapy.
## Adult Dosing
Dosing varies significantly based on indication and severity. Common regimens include:
* **Bacterial Vaginosis:** 500 mg orally twice daily for 7 days, or a single 2-gram dose orally. Alternatively, 0.75% vaginal gel applied once daily for 5 days.
* **Trichomoniasis:** 2 grams orally as a single dose or 250 mg orally three times daily for 7 days, or 375 mg orally twice daily for 7 days.
* **Amebiasis (intestinal):** 500-675 mg orally three times daily for 5-10 days.
* **Amebiasis (hepatic abscess):** 500-750 mg orally three or four times daily for 5-10 days.
* **Giardiasis:** 250 mg orally three times daily for 5 days, or 500 mg orally twice daily for 5 days.
* **Anaerobic bacterial infections:** 500 mg intravenously or orally every 8 hours. Duration depends on infection severity and clinical response. Maximum dose generally 4 grams/day.
## Pediatric Dosing
Dosing is weight-based and depends on the indication.
* **Intravenous dosing for serious anaerobic infections:** 15 mg/kg per dose every 8 hours, not to exceed 4 grams/day.
* **Alternative effective regimens may exist for specific pediatric indications.** Consult pediatric infectious disease guidelines or local protocols.
## Dose Adjustments
No dose adjustment is typically necessary in renal impairment, though prolonged high doses may warrant caution. Significant hepatic impairment may require dose reduction; consult prescribing information or liver transplant protocols.
## Contraindications
* Hypersensitivity to metronidazole or other nitroimidazole derivatives.
* Use with disulfiram (within 14 days) or alcohol (within 3 days) due to disulfiram-like reaction.
## Adverse Effects
Common: Nausea, vomiting, diarrhea, metallic taste, anorexia, abdominal pain, headache, dizziness.
Serious: Peripheral neuropathy (especially with prolonged use), seizures, encephalopathy, aseptic meningitis, Stevens-Johnson syndrome, toxic epidermal necrolysis, leukopenia, pancreatitis, severe allergic reactions.
## Key Drug Interactions
* **Alcohol:** Disulfiram-like reaction (flushing, nausea, vomiting, headache, palpitations). Avoid concurrent use and for at least 3 days after discontinuation.
* **Warfarin:** Increased anticoagulant effect. Monitor INR closely and adjust warfarin dose as needed.
* **Lithium:** Metronidazole may increase lithium levels, potentially leading to toxicity. Monitor lithium levels.
* **Phenytoin/Phenobarbital:** May decrease metronidazole efficacy.
* **Disulfiram:** Risk of psychotic reactions. Avoid concurrent use.
## Monitoring
* Monitor for signs and symptoms of peripheral neuropathy (numbness, tingling, pain). Discontinue if neurological symptoms occur.
* Monitor for gastrointestinal upset.
* Monitor for signs of hypersensitivity reactions.
* For severe infections or prolonged therapy, consider CBC.
## Clinical Pearls
* Metronidazole has activity against anaerobic bacteria and protozoa.
* A disulfiram-like reaction can occur with alcohol. Educate patients to avoid alcohol consumption during and for at least 3 days after completing therapy.
* Metallic taste is a common side effect.
* May turn urine reddish-brown.
* Oral metronidazole is often used for mild C. difficile colitis, but vancomycin is generally preferred for severe cases.
***
**Disclaimer:** This information is for educational purposes only and does not substitute for professional medical advice. Always verify current prescribing information with the manufacturer's product labeling or consult with a qualified healthcare provider.
