Metronidazole important information (Uses, side effects)

What is metronidazole?

Metronidazole is an antibiotic that fights bacteria.

Metronidazole is used to treat bacterial infections of the vagina, stomach, liver, skin, joints, brain, and respiratory tract.

Metronidazole will not treat a vaginal yeast infection.

Important information

You should not use metronidazole if you are allergic to it, or if you have taken disulfiram (Antabuse) within the past 2 weeks.

Do not drink alcohol or consume foods or medicines that contain propylene glycol while you are taking metronidazole and for at least 3 days after you stop taking it. You may have unpleasant side effects such as fast heartbeats, warmth or redness under your skin, tingly feeling, nausea, and vomiting.

This medicine will not treat a viral infection such as the common cold or flu.

In animal studies, this medicine caused certain types of cancers or tumors. It is not known whether these effects would occur in people using this medicine. Ask your doctor about your risk.

Before taking this medicine

You should not take metronidazole if you are allergic to it, or if you have taken disulfiram (Antabuse) within the past 2 weeks.

To make sure metronidazole is safe for you, tell your doctor if you have ever had:

liver disease;
kidney disease;
a stomach or intestinal disease such as Crohn’s disease;
a blood cell disorder such as anemia (lack of red blood cells) or low white blood cell (WBC) counts;
a fungal infection anywhere in your body; or
a nerve disorder.

In animal studies, metronidazole caused certain types of tumors, some of which were cancerous. However, very high doses are used in animal studies. It is not known whether these effects would occur in people using regular doses. Ask your doctor about your risk.

Using metronidazole during pregnancy could harm the unborn baby. Tell your doctor if you are pregnant or if you become pregnant while using this medicine.

Metronidazole can pass into breast milk and may harm a nursing baby. You should not breast-feed within 24 hours after using this medicine. If you use a breast pump during this time, throw out any milk you collect. Do not feed it to your baby.

Do not give this medicine to a child without medical advice.

Metronidazole side effects

Get emergency medical help if you have signs of an allergic reaction to metronidazole: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

severe stomach pain, diarrhea that is watery or bloody;
trouble sleeping, depression, feeling irritable;
headache, dizziness, weakness;
a light-headed feeling (like you might pass out); or
blisters or ulcers in your mouth, red or swollen gums, trouble swallowing.

Stop taking the medicine and call your doctor right away if you have neurologic side effects (more likely to occur while taking metronidazole long term):

numbness, tingling, or burning pain in your hands or feet;
vision problems, pain behind your eyes, seeing flashes of light;
muscle weakness, problems with coordination;
trouble speaking or understanding what is said to you;
a seizure; or
fever, neck stiffness, and increased sensitivity to light.

Side effects may be more likely in older adults.

Common metronidazole side effects may include:

nausea, vomiting, loss of appetite, stomach pain;
diarrhea, constipation;
unpleasant metallic taste;
rash, itching;
vaginal itching or discharge;
mouth sores; or
swollen, red, or “hairy” tongue.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.