Metronidazole can cause cancer in laboratory animals. Talk to your doctor about the risks and benefits of taking this medication.
Why is this medication prescribed?
Metronidazole capsules and tablets are used to treat infections of the reproductive system, gastrointestinal (GI) tract, skin, heart, bone, joint, lung, blood, nervous system, and other areas of the body. Metronidazole capsules and tablets are also used to treat sexually transmitted diseases (STDs). Metronidazole extended-release (long-acting) tablets are used to treat bacterial vaginosis (an infection caused by too much of certain types of harmful bacteria in the vagina) in women. Metronidazole is in a class of medications called nitroimidazole antimicrobials. It works by stopping the growth of bacteria.
Antibiotics will not work for colds, flu, or other viral infections. Using antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment.
How should this medicine be used?
Metronidazole comes as a tablet, an extended-release tablet, and as a capsule to take by mouth. Metronidazole capsules and tablets are usually taken as a one-time dose (or divided into two doses on 1 day) or two to four times daily for up to 10 days or longer. Metronidazole extended-release tablets are usually taken once daily at least 1 hour before or 2 hours after a meal for 7 days. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take metronidazole exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Swallow the extended-release tablets whole; do not split, chew, or crush them.
Continue to take this medication even if you feel well. Do not stop taking it without talking to your doctor. If you stop taking this medication too soon or skip doses, your infection may not be completely treated and the bacteria may become resistant to antibiotics.
Other uses for this medicine
Metronidazole tablets are used to treat bacterial vaginosis in women.
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
What special precautions should I follow?
Before taking metronidazole,
- tell your doctor and pharmacist if you are allergic to metronidazole, secnidazole (Solosec), tinidazole (Tindamax), any other medications, or any of the ingredients in metronidazole preparations. Ask your pharmacist for a list of the ingredients.
- tell your doctor if you are taking or have taken disulfiram (Antabuse). Your doctor may tell you not to take metronidazole if you are taking disulfiram or have taken it within the past 2 weeks.
- tell your doctor and pharmacist what prescription, nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: anticoagulants ('blood thinners') such as warfarin (Coumadin, Jantoven), busulfan (Busulfex, Myleran), cimetidine (Tagamet HB), lithium (Lithobid), phenobarbital, and phenytoin (Dilantin, Phenytek).
- tell your doctor if you have or have ever had Crohn's disease, or blood, kidney, or liver disease.
- tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking metronidazole, call your doctor. Women who are pregnant generally should not take metronidazole during the first trimester (first 3 months) of pregnancy.
- do not drink alcoholic beverages or take products with alcohol or propylene glycol while taking this medication and for at least 3 days after your final dose. Alcohol and propylene glycol may cause nausea, vomiting, stomach cramps, headache, sweating, and flushing (redness of the face) when taken with metronidazole.
What should I do if I forget a dose?
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
What side effects can this medication cause?
Metronidazole may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- upset stomach
- stomach cramps
- loss of appetite
- dry mouth
- sharp, unpleasant metallic taste
- furry tongue; mouth or tongue irritation
Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately:
- numbness, pain, burning, or tingling in your hands or feet
- peeling or blistering skin
- stuffy nose, fever, sore throat, or other signs of infection
- joint pain
- difficulty speaking
- problems with coordination
Metronidazole may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).
What should I know about storage and disposal of this medication?
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from light, excess heat and moisture (not in the bathroom).
It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org
Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.
In case of emergency/overdose
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.
Symptoms of overdose may include the following:
- loss of muscle coordination
- numbness, pain, burning, or tingling in your hands or feet
What other information should I know?
Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your response to metronidazole.
Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking metronidazole.
Do not let anyone else take your medication. Your prescription is probably not refillable. If you still have symptoms of infection after you finish the metronidazole, call your doctor.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
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