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Flagyl IV

Precautions and Side Effects


Generic Name: METRONIDAZOLE - INJECTION
Pronounced: (meh-trow-NID-uh-zole)

Flagyl IV Side Effects

Table of Contents

Dizziness, headache, diarrhea, nausea, vomiting, stomach upset, or a metallic taste in the mouth may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

This drug may cause urine to darken. This is harmless.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these unlikely but serious side effects occur:

  • unsteadiness
  • seizures
  • mental/mood changes (e.g., confusion)
  • numbness/tingling of hands/feet


Tell your doctor immediately if any of these rare but very serious side effects occur:

  • sore throat
  • persistent fever
  • unusual bleeding/bruising
  • severe stomach pain
  • persistent nausea/vomiting


This medication may be used to treat a severe intestinal condition (pseudomembranous colitis) due to a type of resistant bacteria. However, sometimes treatment with metronidazole for other types of infections may also cause this intestinal condition. Tell your doctor immediately if you develop: persistent diarrhea, abdominal or stomach pain/cramping, or blood/mucus in your stool. This condition may occur weeks after treatment with antibiotics has stopped. Do not use anti-diarrhea products or narcotic pain medications if you have these symptoms because these products may make them worse.

Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including:

  • rash
  • itching
  • swelling
  • severe dizziness
  • trouble breathing


This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

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8 weeks of vomiting, nausea, acid reflux, that comes and goes. Sometimes stomach pain during/after.

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