metronidazole, Flagyl (cont.)

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DOSING: Metronidazole may be taken orally with or without food. In the hospital, metronidazole can be administered intravenously to treat serious infections. The liver is primarily responsible for eliminating metronidazole from the body, and doses may need to be reduced in patients with liver disease and abnormal liver function.

Various metronidazole regimens are used. Some examples are listed below.

  • Amebic dysentery: 750 mg orally 3 times daily for 5-10 days

  • Amebic liver abscess: 500-750 mg orally three times daily for 5-10 days

  • Anaerobic infections: 7.5 mg/kg orally every 6 hours not to exceed 4 grams daily

  • Bacterial Vaginosis: 750 mg (extended release tablets) once daily for 7 days. One applicator-full of 0.75% vaginal gel, once or twice daily for 5 days.

  • Clostridium difficile infection: 250-500 mg orally 4 times daily or 500-750 orally 3 times daily

  • Giardia: 250 mg orally three times daily for 5 days

  • Helicobacter pylori: 800-1500 mg orally daily for several days in combination with other drugs.

  • Pelvic inflammatory disease (PID): 500 mg orally twice daily for 14 days in combination with other drugs.

  • Trichomoniasis: 2 g single dose or 1 g twice

  • Rosacea: apply topical gel 0.75-1% once daily

DRUG INTERACTIONS: Alcohol should be avoided because metronidazole and alcohol together can cause severe nausea, vomiting, cramps, flushing, and headache.

Metronidazole can increase the blood thinning effects of warfarin (Coumadin) and increase the risk of bleeding probably by reducing the break down of warfarin.

Cimetidine (Tagamet) increases blood levels of metronidazole while cholestyramine reduces blood levels of metronidazole by reducing its absorption.

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