What side effects are possible with this medication?

A side effect is an unwanted response to a medication when it is taken in normal doses. A side effect may be mild or severe, temporary or permanent, but does not occur in everyone. Not everyone will experience side effects, and which side effects a person experiences cannot be anticipated.

The following side effects have been reported by at least 1% of people taking this medication. If you develop any of these side effects (or any other side effects not listed here) or they change in intensity, speak to your doctor or pharmacist for advice on managing them and on the risks and benefits of the medication.

• any vaginal irritation, discharge, or dryness not present before use of this medicine
• change in taste sensation
• diarrhea
• dizziness or lightheadedness
• headache
• heartburn
• loss of appetite
• nausea
• skin rash, hives, redness, or itching
• stomach pain or cramps
• unpleasant or sharp metallic taste
• vomiting

Click here to learn about serious side effects that can potentially occur with any medication. These examples are provided for information purposes only and are not meant to be exhaustive. Always consult your doctor for sound medical advice specific to your particular medication and treatment.

Are there any other precautions or warnings for this medication?

Be sure to inform your doctor of all your medical conditions before you begin taking a medication. Some conditions can affect how you should take this medication.

Alcohol: Severe side effects including nausea and vomiting may occur if you consume alcohol while taking metronidazole. It is recommended to wait at least one day after finishing metronidazole treatment before drinking alcohol again.

Blood problems: People with certain blood problems should use this medication with caution as it may cause low white blood cell counts.

Liver disease: Patients with severe liver disease metabolize metronidazole slowly. For such people, metronidazole should be taken with caution.

Neurological side effects: Stop treatment with metronidazole and see your doctor if muscle incoordination, seizures, or numbness or tingling in the hands or feet occur.

Occupational hazards: This medication may cause confusion or dizziness. Avoid driving or other tasks requiring alertness if the medication affects you in this way.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication passes into breast milk. If you are a breast-feeding mother and are taking metronidazole, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

What other drugs could interact with this medication?

An interaction between medications does not always mean that you must stop taking one of them. The following medications may affect the way metronidazole works, be affected by metronidazole, or increase the risk of side effects:

• alcohol
• barbiturates (e.g., phenobarbital, primidone, butalbital)
• disulfiram
• lithium
• phenytoin
• warfarin

If you are taking any of these or other medications (including non-prescription, herbal, and supplement products), speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want to change your therapy or may suggest ways of managing any interactions. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your doctor know if you use them. Medications other than those listed above may also interact with this medication.