Metronidazole Noridem (Metronidazole)

Metronidazole is employed to manage infections caused by anaerobic bacteria and certain protozoa.

• Anaerobic bacterial infections: eliminates pathogenic anaerobes in intra‑abdominal, pelvic, and soft‑tissue infections.
• Bacterial vaginosis: restores normal vaginal flora by targeting Gardnerella and other anaerobes.
• Trichomoniasis: eradicates Trichomonas vaginalis, relieving symptoms and preventing transmission.
• Amoebiasis: treats intestinal and extra‑intestinal Entamoeba histolytica infections.
• Clostridioides difficile infection: reduces toxin‑producing C. difficile, aiding clinical recovery.

• Metronidazole is taken up by anaerobic microorganisms and reduced by intracellular electron‑transport proteins to reactive nitro radicals. These radicals interact with DNA, causing strand breaks and loss of helical structure, which inhibits nucleic acid synthesis and leads to cell death, while aerobic cells are largely unaffected.

Metronidazole may cause a range of adverse reactions, most of which are dose‑related and reversible upon discontinuation.

Common Side Effects

• Nausea: mild to moderate upset stomach.
• Metallic taste: transient metallic sensation in the mouth.
• Headache: occasional dull or throbbing pain.
• Diarrhea: loose stools that resolve after therapy.
• Dark urine: harmless discoloration of urine.

Serious or Rare Side Effects

• Peripheral neuropathy: tingling or numbness in extremities.
• Seizures: rare convulsive episodes.
• Stevens‑Johnson syndrome: severe skin and mucous membrane reaction.
• Hepatotoxicity: elevated liver enzymes or jaundice.
• Hypersensitivity: rash, fever, or anaphylaxis.

Before initiating therapy, clinicians should consider patient‑specific factors and monitor for potential complications.

• Renal impairment: adjust dosing or monitor serum levels in severe dysfunction.
• Hepatic disease: use with caution; monitor liver function tests.
• Alcohol consumption: advise avoidance of alcohol due to disulfiram‑like reaction.
• Pregnancy and lactation: evaluate risk‑benefit ratio; limited safety data available.
• Concomitant neurotoxic drugs: avoid or monitor for additive neuropathy.
• Store at ambient temperature: keep in original container, protect from moisture and direct sunlight.

Metronidazole can alter the activity of several co‑administered medicines, requiring careful management.

Major Interactions (Avoid)

• Disulfiram: may cause severe flushing, tachycardia, and hypotension.
• Warfarin: potentiates anticoagulant effect, increasing bleeding risk.
• Lithium: can raise serum lithium levels, leading to toxicity.

Moderate Interactions (Monitor Closely)

• Phenytoin: may reduce phenytoin concentrations.
• Cimetidine: can increase metronidazole plasma levels.
• Alcohol: concurrent use may precipitate a disulfiram‑like reaction.