From the Guidelines
Flagyl, also known as metronidazole, is an antibiotic medication primarily used to treat infections caused by anaerobic bacteria and certain parasites, with a recommended dose of 500 mg orally twice a day for 7 days for bacterial vaginosis, or 2 g orally in a single dose for trichomoniasis, as per the most recent guidelines 1.
Common Uses of Flagyl
- Bacterial vaginosis
- Trichomoniasis
- Giardiasis
- Amoebiasis
- Anaerobic bacterial infections, including Clostridium difficile colitis
Important Considerations
- Patients should complete the full course of treatment even if symptoms improve before finishing
- Important side effects include a metallic taste in the mouth, nausea, headache, and a disulfiram-like reaction with alcohol that causes flushing, headache, and vomiting, so alcohol should be avoided during treatment and for at least 48 hours after completing the medication 1
- Flagyl may darken urine and can interact with certain medications like warfarin, so patients should inform their healthcare provider about all medications they are taking
Dosage and Administration
- The typical adult dose ranges from 250-500 mg taken orally three times daily for 7-14 days, depending on the specific infection being treated
- For severe infections, intravenous administration may be necessary
- For trichomoniasis, a single dose of 2 g orally is recommended, while for bacterial vaginosis, 500 mg orally twice a day for 7 days is recommended 1
Mechanism of Action
- Flagyl works by disrupting the DNA of susceptible microorganisms, preventing them from reproducing and ultimately killing them 1
From the FDA Drug Label
To reduce the development of drug-resistant bacteria and maintain the effectiveness of metronidazole tablets and other antibacterial drugs, metronidazole tablets should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria. Patients should be counseled that antibacterial drugs including metronidazole tablets should only be used to treat bacterial infections.
The use of Flagyl (Metronidazole) is to treat or prevent bacterial infections that are proven or strongly suspected to be caused by bacteria 2, 2.
- Bacterial infections include those caused by anaerobic bacteria, as well as trichomoniasis and amebiasis.
- Metronidazole should only be used to treat bacterial infections, and not viral infections such as the common cold.
From the Research
Use of Flagyl (Metronidazole)
- Flagyl, also known as Metronidazole, is used to treat various protozoal infections, including:
- Metronidazole is effective against certain Gram-negative anaerobic bacilli, including Bacteroides spp. 3
- It is often used as an alternative to tinidazole, although tinidazole may have a longer half-life and require single-dose or once-daily administration 3, 5
- Metronidazole is typically administered in multiple daily doses, whereas tinidazole can be given in a single dose or once daily 6, 5
- The efficacy of metronidazole in treating giardiasis is comparable to tinidazole, but it may require a longer treatment duration 6, 7