Metronidazole is an antibiotic. It fights bacteria in your body. Metronidazole is used to treat bacterial infections of the vagina, stomach, skin, joints, and respiratory tract. This medication will not treat a vaginal yeast infection. Metronidazole may also be used for purposes not listed in this medication guide.

The health and medical information provided here is for general purposes only and is not a substitute for the expertise and judgment of your physician, or other health care professional. It should not be understood to indicate that the use of this medicine is safe, appropriate or effective for you. Always consult your health care professional before using this, or any other, drug.

ake metronidazole for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Metronidazole will not treat a viral infection such as the common cold or flu. Do not drink alcohol 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.

Get emergency medical help if you have any of these signs of an allergic reaction to metronidazole: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have any of these serious side effects:
numbness or tingling in your hands or feet;
white patches or sores inside your mouth or on your lips;
pain or burning when you urinate;
diarrhea that is watery or bloody;
vision problems, pain behind your eyes;
trouble concentrating, slurred speech, mood or behavior changes, tremors, muscle twitching, seizure (convulsions);
fever, chills, muscle pain, confusion, headache, sore throat, neck stiffness, increased sensitivity to light, drowsiness, nausea and vomiting; or
severe skin reaction -- fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.
Less serious metronidazole side effects may include:
stomach pain, diarrhea;
dizziness, loss of balance;
vaginal itching or discharge;
dry mouth or unpleasant metallic taste;
cough, sneezing, runny or stuffy nose; or
swollen or sore tongue.

Take metronidazole exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.
Take the extended-release metronidazole tablet (Flagyl ER) on an empty stomach, at least 1 hour before or 2 hours after eating a meal. Do not crush, chew, or break an extended-release tablet. Swallow it whole. Breaking the pill may cause too much of the drug to be released at one time. Take metronidazole for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Metronidazole will not treat a viral infection such as the common cold or flu.
To be sure metronidazole is not causing harmful effects, your blood may need to be tested often. Your liver function may also need to be tested. Visit your doctor regularly.
This medication can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using metronidazole.