Last reviewed 2026-04-22 · How we verify

Metronidazole (ST14)

Metronidazole is a nitroimidazole antibiotic that disrupts bacterial and parasitic DNA by generating reactive oxygen species after reduction of its nitro group.

Metronidazole is a nitroimidazole antibiotic that disrupts bacterial and parasitic DNA by generating reactive oxygen species after being reduced in anaerobic environments. Used for Anaerobic bacterial infections, Trichomoniasis, Amebiasis.

At a glance

Mechanism of action

The drug is activated by anaerobic bacteria and parasites through reduction of its 5-nitro group, generating cytotoxic free radicals that damage DNA and prevent replication. This mechanism makes it effective against obligate anaerobes and certain protozoan parasites. It has no activity against aerobic organisms due to their inability to activate the drug.

Approved indications

• Anaerobic bacterial infections (intra-abdominal, gynecological, respiratory)
• Trichomoniasis
• Giardiasis
• Amebiasis
• Clostridioides difficile infection
• Bacterial vaginosis

Common side effects

• Metallic taste
• Nausea
• Headache
• Peripheral neuropathy (with prolonged use)
• Disulfiram-like reaction with alcohol
• Diarrhea

Key clinical trials

• Sequential Versus Quadruple Therapy in the Second-line Treatment (PHASE4)

Primary sources

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Competitive intelligence

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• National Taiwan University Hospital portfolio CI