Flagyl Dosage: Metronidazole 500mg/250mg

Metronidazole is a popular antibacterial and antiprotozoal agent. It is sometimes used as a therapeutic agent and in some cases it is utilised as surgical prophylaxis. In this article, we shall briefly review the different doses of metronidazole used in clinical practice.

Metronidazole is available in different forms and variable doses. Tablets are available in 250 mg and 500 mg doses. Depending on the underlying illness and indication, the doses are often variable as is the duration of treatment. For example, in patients with liver abscess, metronidazole they be given in doses of 500 mg or 750 mg orally three times a day for up to 10 days.

On the other hand, in more serious infections, metronidazole is described as an intravenous drug. Prescription depends on the way to the patient and no more than 4 g a day is prescribed in a 24-hour period.

Some of the clinical conditions in which metronidazole if used include –

• Amoebiasis – 500 to 750 mg three times a day for up to 10 days
• Pseudomembranous colitis due to Clostridium difficile - 500 mg orally four times a day for up to 2 weeks.
• Acute Crohn's disease - 250 mg four times a day orally.
• Helicobacter pylori infection - 250 mg four times a day orally. Often this is combined with amoxicillin and omeprazole as a part of triple therapy. Treatment teams can vary and can sometimes extend up to 2 weeks.
• Pelvic inflammatory disease - Metronidazole is often combined with doxycycline to treat pelvic inflammatory disease. Doses can vary but is often prescribed at 500 mg orally twice a day. Metronidazole is useful as outpatient therapy but is not prescribed as such for patients in hospital.
• Aspiration pneumonia often requires intravenous metronidazole as a part of combination treatments with other antibiotics. The dose is calculated according to body weight and is often prescribed and 7.5 mg per kilogram intravenously four times a day.
• Infective endocarditis affecting the cardiac valves requires a similar dose of intravenous metronidazole at 7.5 mg per kilogram every six hours.
• Giardiasis requires oral treatment at 250 mg three times a day.

As is seen, metronidazole is useful for a variety of clinical conditions. The available doses range between 250 mg to 750 mg doses orally though intravenous medication depends upon body weight. Paediatric doses also vary similarly. High dose metronidazole is prescribed orally at 30 to 50 mg per kilogram per day administered in three divided doses for up to 10 days in children to manage amoebiasis.

It is strongly recommended that before taking any medication that you seek medical advice. Metronidazole should be taken but no longer than the duration it has been prescribed for.