Metronidazolo Aurobindo (Metronidazole)

Metronidazole is used to treat infections caused by anaerobic bacteria and certain protozoa.

• Bacterial vaginosis: eradicates Gardnerella and associated anaerobes, restoring normal vaginal flora.
• Trichomoniasis: eliminates Trichomonas vaginalis, relieving symptoms and preventing transmission.
• Amoebiasis: clears intestinal Entamoeba histolytica infection, reducing dysentery and hepatic involvement.
• Anaerobic bacterial infections: resolves intra‑abdominal, skin and soft‑tissue infections caused by susceptible anaerobes.
• Clostridioides difficile‑associated diarrhea (adjunct therapy): reduces toxin‑producing bacterial load when used with standard therapy.

• Metronidazole enters susceptible anaerobic microorganisms and is reduced by intracellular redox proteins, converting its nitro group into reactive nitroso radicals. These metabolites bind to DNA, causing strand breakage and inhibiting nucleic acid synthesis, which leads to bacterial or protozoal cell death. The selective activation in low‑oxygen environments accounts for its efficacy against anaerobes while sparing most aerobic cells.

Metronidazole may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Nausea: mild stomach upset or queasiness.
• Metallic taste: transient metallic sensation in the mouth.
• Diarrhea: loose stools, often self‑limiting.
• Headache: mild to moderate head pain.

Serious or Rare Side Effects

• Seizures: rare neurologic events requiring immediate medical attention.
• Peripheral neuropathy: tingling or numbness in extremities, potentially irreversible.
• Severe allergic reaction: rash, itching, swelling, or difficulty breathing (anaphylaxis).

Before prescribing Metronidazole, consider the following precautions to ensure safe use.

• Pregnancy: Category B – generally considered safe, but use only if clearly needed.
• Breastfeeding: Small amounts excreted in milk; weigh benefits against potential infant effects.
• Alcohol interaction: Avoid alcohol; may cause disulfiram‑like reaction with flushing and tachycardia.
• Liver impairment: Adjust therapy in patients with hepatic dysfunction due to metabolism reliance.
• Renal impairment: Monitor dosing in severe renal failure as accumulation may occur.
• Store at ambient temperature: keep below 25 °C, retain in original packaging, protect from moisture.

Metronidazole can interact with several medicines; awareness of major and moderate interactions helps prevent adverse outcomes.

Major Interactions (Avoid)

• Alcohol: causes disulfiram‑like reaction with flushing, nausea, tachycardia.
• Warfarin: may enhance anticoagulant effect, increasing bleeding risk.
• Lithium: can raise lithium levels, leading to toxicity.

Moderate Interactions (Monitor Closely)

• Cimetidine: may increase metronidazole plasma concentrations.
• Phenytoin: may reduce metronidazole levels, decreasing efficacy.
• Oral contraceptives: may reduce contraceptive effectiveness; advise additional barrier methods.