Metronidazole Uses, Dosage & Side Effects

Metronidazole                                                    

Generic Name: metronidazole ( me troe NI da zole )

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.

Important information

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. 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.

Before taking this medicine

You should not use this medication 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 metronidazole, 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 this medication.

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.

Metronidazole Side Effects

More common

• Agitation
• back pain
• blindness
• blurred vision
• burning, numbness, tingling, or painful sensations in the hands or feet
• changes in speech patterns
• confusion
• convulsions
• decreased vision
• depression
• dizziness
• drowsiness
• eye pain
• fever
• hallucinations
• headache
• irritability
• lack of coordination
• nausea
• seizures
• shakiness and unsteady walk
• slurred speech
• stiff neck or back
• trouble speaking
• unsteadiness, trembling, or other problems with muscle control or coordination
• unusual tiredness or weakness
• vomiting
• weakness in the arms, hands, legs, or feet

Less common

• Black, tarry stools
• blood in the urine or stools
• body aches or pain
• chills
• clumsiness or unsteadiness
• difficulty with breathing
• ear congestion
• feeling of pelvic pressure
• frequent or painful urination
• loss of voice
• nasal congestion
• pinpoint red spots on the skin
• runny nose
• skin rash, hives, redness, or itching
• sneezing
• stomach and back pain (severe)
• unusual bleeding or bruising
• vaginal irritation, discharge, or dryness not present before taking the medicine

Rare

• Bleeding gums
• bloating
• chest pain
• constipation
• cough
• dark-colored urine
• fast heartbeat
• indigestion
• loss of appetite
• painful or difficult urination
• pains in the stomach, side, or abdomen, possibly radiating to the back
• sore throat
• sores, ulcers, or white spots on the lips or in the mouth
• swollen glands
• yellow eyes or skin

Incidence not known

• Blistering, peeling, or loosening of the skin
• bloody or cloudy urine
• burning while urinating
• continuing diarrhea
• continuing stomach pain
• diarrhea
• feeling of warmth
• increased volume of pale, dilute urine
• joint or muscle pain
• loss of bladder control
• red skin lesions, often with a purple center
• red, irritated eyes
• redness of the face, neck, arms, and occasionally, upper chest
• redness of the skin

How should I take metronidazole?

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.

Store metronidazole at room temperature away from moisture and heat.

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 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.

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 metronidazole and call your doctor. Do not use anti-diarrhea medicine unless your doctor tells you to.

Metronidazole side effects

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.

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 metronidazole?

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 metronidazole. 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.