What is Flagyl?

Flagyl may also be used for purposes not listed in this medication guide.

Important information

Take Flagyl 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. Flagyl will not treat a viral infection such as the common cold or flu. Do not drink alcohol while you are taking Flagyl 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.

Before taking this medicine

You should not use Flagyl if you are allergic to metronidazole, or if you are in the first trimester of pregnancy. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

Before taking Flagyl, tell your doctor if you are allergic to any drugs, or if you have:

• liver disease;

• a stomach or intestinal disease such as Crohn's disease;

• a blood cell disorder such as anemia (lack of red blood cells) or leukopenia (lack of white blood cells);

• epilepsy or other seizure disorder; or

• nerve disorders.

If you have any of these conditions, you may need a dose adjustment or special tests to safely take Flagyl.

Metronidazole can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

How should I take Flagyl?

Take Flagyl 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 Flagyl 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. Flagyl will not treat a viral infection such as the common cold or flu.

To be sure Flagyl 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 Flagyl.

Store Flagyl at room temperature away from moisture and heat.

See also: Dosage Information (in more detail)

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include nausea, vomiting, dizziness, loss of balance or coordination, numbness and tingling, or seizures (convulsions).

What should I avoid?

Do not drink alcohol while you are taking Flagyl 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.

Check the labels of any medicines or food products you use to make sure they do not contain alcohol.

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, stop taking Flagyl and call your doctor. Do not use anti-diarrhea medicine unless your doctor tells you to.

Flagyl side effects

Get emergency medical help if you have any of these signs of an allergic reaction to Flagyl: 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 while using Flagyl:

• 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 Flagyl 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.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

What other drugs will affect Flagyl?

Tell your doctor about all other medicines you use, especially:

• cimetidine (Tagamet);

• seizure medication such as phenytoin (Dilantin) or phenobarbital (Luminal, Solfoton);

• a blood thinner such as warfarin (Coumadin, Jantoven);

• lithium (Lithobid, Eskalith, others); or

• disulfiram (Antabuse).

This list is not complete and other drugs may interact with Flagyl. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.