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Frequently Asked Questions
You should not use metronidazole 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.
Metronidazole is an antibiotic that 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.
Metronidazole may also be used for purposes not listed in this medication guide.
You should not take metronidazole if you are allergic to it, or if you have taken disulfiram (Antabuse) within the past 2 weeks.
Do not take metronidazole during the first trimester of pregnancy. This medicine can harm an unborn baby. Tell your doctor if you are pregnant.
Tell your doctor if you have ever had:
- liver or kidney disease;
- Cockayne syndrome (a rare genetic disorder);
- 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.
Metronidazole can pass into breast milk and may harm a nursing baby. You should not breast-feed within 24 hours after using metronidazole. 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.
Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.
Shake the oral suspension (liquid) before you measure a dose. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).
Do not crush, chew, or break an extended-release tablet. Swallow it whole.
If you are treating a vaginal infection, your sexual partner may also need to take metronidazole (even if no symptoms are present) or you could become reinfected.
Metronidazole is usually given for up to 10 days in a row. You may need to repeat this dosage several weeks later.
Use this medicine for the full prescribed length of time, even if your symptoms quickly improve. Skipping doses can increase your risk of infection that is resistant to medication. Metronidazole will not treat a viral infection such as the flu or a common cold.
This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using metronidazole.
Store at room temperature away from moisture and heat.
Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
Overdose symptoms may include nausea, vomiting, and loss of balance or coordination.
Do not drink alcohol or consume food or medicines that contain propylene glycol while you are taking metronidazole. You may have unpleasant side effects such as headaches, stomach cramps, nausea, vomiting, and flushing (warmth, redness, or tingly feeling).
Avoid alcohol or propylene glycol for at least 3 days after you stop taking metronidazole. Check the labels of any medicines or food products you use to make sure they do not contain alcohol or propylene glycol.
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
- painful or difficult urination;
- trouble sleeping, depression, irritability;
- 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.
Metronidazole can cause life-threatening liver problems in people with Cockayne syndrome. If you have this condition, stop taking metronidazole and contact your doctor if you have signs of liver failure--nausea, stomach pain (upper right side), dark urine, clay-colored stools, or jaundice (yellowing of the skin or eyes).
Side effects may be more likely in older adults.
Common 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. You may report side effects to FDA at 1-800-FDA-1088.
Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.
Tell your doctor about all your other medicines, especially:
- lithium; or
- a blood thinner--warfarin, Coumadin, Jantoven.
This list is not complete. Other drugs may affect metronidazole, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.
Your pharmacist can provide more information about metronidazole.
|Brand Name Examples||Supplied As||Strength|
|Flagyl||tablet||250 mg500 mg|
|Flagyl 375||capsule||375 mg|
|Generic Examples||Supplied As||Strength|
|MetroNIDAZOLE||tablet||250 mg500 mg|