Metronidazole can cause cancer in laboratory animals. Talk to your doctor about the risks and benefits of using this medication.
Metronidazole eliminates bacteria and other microorganisms that cause infections of the reproductive system, gastrointestinal tract, skin, vagina, and other areas of the body. Antibiotics will not work for colds, flu, or other viral infections.
This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.
Metronidazole comes as a tablet to take by mouth. It is usually taken two or three times a day for 5 to 10 days or longer. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take metronidazole exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Before taking metronidazole,
- tell your doctor and pharmacist if you are allergic to metronidazole or any other drugs.
- tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially anticoagulants ('blood thinners') such as warfarin (Coumadin), astemizole (Hismanal), disulfiram (Antabuse), lithium (Lithobid), phenobarbital, phenytoin (Dilantin), and vitamins.
- tell your doctor if you have or have ever had blood, kidney, or liver disease or Crohn's disease.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking metronidazole, call your doctor.
- know that you should not drink alcohol while taking this drug. Alcohol may cause an upset stomach, vomiting, stomach cramps, headaches, sweating, and flushing (redness of the face).
- plan to avoid unnecessary or prolonged exposure to sunlight and to wear protective clothing, sunglasses, and sunscreen. Metronidazole may make your skin sensitive to sunlight.
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
Metronidazole may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- upset stomach
- loss of appetite
- dry mouth; sharp, unpleasant metallic taste
- dark or reddish-brown urine
- furry tongue; mouth or tongue irritation
- numbness or tingling of hands or feet
If you experience any of the following symptoms, call your doctor immediately:
- stuffy nose
- joint pain
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at Web Site] or by phone [1-800-332-1088].
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your response to metronidazole.
Do not let anyone else take your medication. Your prescription is probably not refillable. If you still have symptoms of infection after you finish the metronidazole, call your doctor.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.
Last Reviewed: September 1, 2010.