Metronidazole Injection is a parenteral form of the antibiotic metronidazole, used for treating serious anaerobic bacterial and certain protozoal infections when oral therapy is not suitable or rapid systemic delivery is needed.

Here are the key details:

1. Composition and Form

• Active ingredient: Metronidazole.

• Supplied as a sterile solution for intravenous (IV) administration.

• Available in varying concentrations depending on the manufacturer.

2. Mechanism of Action

• Metronidazole enters anaerobic bacterial and protozoal cells.

• Undergoes reduction by intracellular electron transport proteins to active metabolites.

• These metabolites bind to DNA, causing strand breakage and inhibition of nucleic acid synthesis.

• The result is cell death, making it bactericidal and trichomonacidal.

3. Indications

• Anaerobic bacterial infections, including:

  • Intra-abdominal infections (peritonitis, abscesses).

  • Skin and soft tissue infections.

  • Gynecologic infections (pelvic inflammatory disease, bacterial vaginosis in systemic infections).

• Protozoal infections: amebiasis, giardiasis, trichomoniasis (when severe or systemic).

• Used when oral administration is not feasible or faster systemic action is required.

4. Administration

• Given intravenously, usually as a slow infusion or IV bolus depending on protocol.

• Dose depends on age, weight, renal function, and severity of infection.

• Typically administered in hospital settings with monitoring for infusion reactions.

5. Side Effects

Common:

• Nausea, vomiting, diarrhea.

• Headache, dizziness.

• Injection site irritation or phlebitis.

Serious / less common:

• Neurotoxicity: peripheral neuropathy, seizures (rare, usually with prolonged therapy).

• Hypersensitivity reactions: rash, urticaria, rarely anaphylaxis.

• Liver enzyme elevations or hepatotoxicity.

• Metallic taste (less relevant with IV but can occur systemically).

6. Contraindications

• Known hypersensitivity to metronidazole or other nitroimidazoles.

• First trimester of pregnancy (use only if benefits outweigh risks).

• Severe hepatic impairment (use with caution).

7. Precautions

• Monitor renal and liver function during prolonged therapy.

• Avoid alcohol during therapy and for at least 48 hours after the last dose due to risk of disulfiram-like reaction.

• Observe for signs of neurotoxicity during extended treatment courses.

• Adjust dose in severe liver dysfunction.

8. Storage

• Store at controlled room temperature, protected from light.

• Use aseptically; discard any unused portion after opening.