What is Flagyl (Metronidazole)?

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Last updated: April 30, 2025View editorial policy

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From the Guidelines

Flagyl is the brand name for metronidazole, an antibiotic medication primarily used to treat infections caused by anaerobic bacteria and certain parasites. It's commonly prescribed for bacterial infections in the gastrointestinal tract, genital area, and other body systems. Typical adult dosages range from 250-500 mg taken orally three times daily for 7-14 days, though this varies based on the specific infection being treated.

Key Points to Consider

  • Metronidazole works by disrupting the DNA of susceptible microorganisms, preventing them from reproducing and ultimately killing them 1.
  • When taking Flagyl, patients should avoid alcohol completely as the combination can cause severe nausea, vomiting, headaches, and flushing (known as a disulfiram-like reaction).
  • Common side effects include metallic taste, nausea, and darkened urine.
  • It's essential to complete the full course of treatment even if symptoms improve before it's finished to ensure the infection is completely eliminated and to reduce the risk of antibiotic resistance.

Dosage Considerations

  • The recommended dosage may vary depending on the specific infection being treated, with some studies suggesting a single dose of 2 g of metronidazole for certain conditions 1.
  • Other studies recommend alternative regimens, such as 500 mg orally twice a day for 7 days 1.

Important Precautions

  • Patients should be aware of the potential side effects and interactions with other medications, including the disulfiram-like reaction with alcohol.
  • It's crucial to follow the prescribed treatment regimen and complete the full course of therapy to ensure effective treatment and prevent antibiotic resistance.

From the FDA Drug Label

Metronidazole is an oral synthetic antiprotozoal and antibacterial agent, 1 (β-hydroxyethyl) 2 methyl 5 nitroimidazole Flagyl is another name for the drug metronidazole, which is an oral synthetic antiprotozoal and antibacterial agent 2.

From the Research

Definition of Flagyl

  • Flagyl is another name for the medication metronidazole 3, 4, 5, 6, 7

Uses of Flagyl

  • It is used to treat various infections, including trichomoniasis, giardiasis, and amebiasis 3
  • Metronidazole is the most widely used nitroimidazole for treating protozoal infections 3

Comparison with Other Medications

  • Tinidazole has a longer half-life than metronidazole, allowing for single-dose or once-daily administration 3
  • Albendazole may be as effective as metronidazole in treating giardiasis, with fewer side effects 4, 6
  • Tinidazole is associated with higher parasitological cure rates than metronidazole and albendazole 5

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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