Metronidazole Special Concept Development (Uk) (Metronidazole)

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

• Bacterial vaginosis: eradicates the anaerobic bacteria responsible for the condition, relieving discharge and odor.
• Trichomoniasis: eliminates Trichomonas vaginalis, resolving genital irritation and discharge.
• Amoebiasis: destroys Entamoeba histolytica trophozoites, treating intestinal and extra‑intestinal disease.
• Anaerobic bacterial infections: targets intra‑abdominal, skin and soft‑tissue infections caused by obligate anaerobes.
• Clostridioides difficile infection (adjunctive): reduces toxin‑producing bacteria when used alongside standard therapy.

• Metronidazole enters susceptible anaerobic cells and is reduced by ferredoxin proteins, generating reactive nitro radicals. These radicals cause DNA strand breakage, inhibit nucleic acid synthesis, and disrupt protein synthesis, leading to cell death of anaerobic bacteria and susceptible protozoa.

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

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 may be watery.
• Abdominal pain: cramping or discomfort in the stomach area.
• Loss of appetite: reduced desire to eat.

Serious or Rare Side Effects

• Seizures: convulsions requiring immediate medical attention.
• Peripheral neuropathy: tingling or numbness in extremities.
• Severe allergic reactions: rash, swelling, or anaphylaxis.
• Stevens‑Johnson syndrome: serious skin blistering.
• Hepatotoxicity: liver enzyme elevations or failure.
• Blood dyscrasias: neutropenia, thrombocytopenia, or anemia.

Before prescribing Metronidazole, clinicians should consider several safety measures.

• Renal and hepatic assessment: evaluate kidney and liver function, especially in patients with impairment.
• Alcohol avoidance: advise patients to abstain from alcohol to prevent disulfiram‑like reactions.
• Pregnancy caution: use only if benefits outweigh potential risks.
• Neurotoxicity monitoring: watch for signs of peripheral neuropathy during prolonged therapy.
• Drug interaction review: check concomitant medications for potential interactions.
• Store at below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Metronidazole can interact with several medicines, requiring careful management.

Major Interactions (Avoid)

• Alcohol: may cause severe flushing, tachycardia, and hypotension.
• Warfarin: can enhance anticoagulant effect, increasing bleeding risk.
• Lithium: may raise lithium levels, leading to toxicity.
• Cyclosporine: increased cyclosporine concentrations may occur.
• Carbamazepine: reduced efficacy of carbamazepine due to enzyme induction.

Moderate Interactions (Monitor Closely)

• Phenytoin: may lower metronidazole levels.
• Phenobarbital: can decrease metronidazole exposure.
• Rifampin: induces metabolism, reducing effectiveness.
• Oral contraceptives: may reduce contraceptive reliability.
• Theophylline: possible increase in theophylline serum concentrations.