Metronidazole Mercury Pharmaceuticals Ltd (Metronidazole)

Metronidazole is indicated for infections caused by anaerobic bacteria and susceptible protozoa. It is used in the following clinical situations:

• Skin infections: resolves anaerobic bacterial skin infections and promotes healing.
• Bacterial vaginosis: eradicates Gardnerella vaginalis and restores normal vaginal flora.
• Amoebiasis: eliminates intestinal Entamoeba histolytica causing dysentery.
• Trichomoniasis: clears Trichomonas vaginalis infection in the genital tract.

• Metronidazole enters anaerobic microorganisms and is reduced by ferredoxin-like proteins to reactive nitro radicals. These radicals interact with DNA, causing strand breakage and loss of helical stability, and also inhibit nucleic acid synthesis. The resulting damage leads to cell death, providing antibacterial and antiprotozoal activity.

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

Common Side Effects

• Nausea: mild to moderate gastrointestinal upset.
• Metallic taste: transient metallic sensation in the mouth.
• Skin irritation: localized redness or itching at the application site.
• Headache: mild headache without neurological signs.
• Diarrhea: loose stools that resolve after discontinuation.

Serious or Rare Side Effects

• Peripheral neuropathy: tingling or numbness in extremities.
• Severe allergic reaction: rash, swelling, or anaphylaxis.
• Seizures: rare central nervous system events.
• Hepatotoxicity: elevated liver enzymes or jaundice.
• Stevens‑Johnson syndrome: severe skin blistering and mucosal involvement.

Before using Metronidazole, consider the following safety measures:

• Pregnancy: Category B – use only if clearly needed after risk‑benefit assessment.
• Breastfeeding: consult a healthcare professional; small amounts may be excreted in milk.
• Liver disease: monitor hepatic function, dose adjustment may be required.
• Neurological disorders: avoid in patients with a history of seizures or neuropathy.
• Alcohol interaction: advise patients to avoid alcohol during treatment and for 48 hours after.
• Store below 25°C: keep in the original container, protect from moisture and light.

Metronidazole can interact with several medicines; awareness helps prevent adverse outcomes.

Major Interactions (Avoid)

• Disulfiram: may cause severe flushing, tachycardia, and hypotension.
• Warfarin: increased anticoagulant effect, risk of bleeding.
• Lithium: elevated lithium levels, potential toxicity.

Moderate Interactions (Monitor Closely)

• Cimetidine: may raise metronidazole plasma concentrations.
• Phenobarbital: may reduce metronidazole effectiveness.
• Alcohol: can precipitate a disulfiram‑like reaction.