This information from Lexicomp® explains what you need to know about this medication, including what it’s used for, how to take it, its side effects, and when to call your healthcare provider.
Brand Names: US
- Metronidazole has been shown to cause cancer in mice and rats with long-term use. Talk with the doctor.
What is this drug used for?
- It is used to treat a certain type of infection (H. pylori) that causes GI (gastrointestinal) ulcers.
What do I need to tell my doctor BEFORE I take this drug?
For all patients taking this drug:
- If you are allergic to this drug; any part of this drug; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
- If you have Cockayne syndrome. Some people with Cockayne syndrome have had liver problems when taking this drug. Sometimes, these liver problems have not gone away or have been deadly.
- If you have any of these health problems: Kidney disease or liver disease.
- If you have ever had a blood problem.
- If you have taken disulfiram within the past 2 weeks.
- If you drink alcohol or take any drugs that have alcohol.
- If you are pregnant or may be pregnant. Do not take this drug if you are pregnant.
- If you are breast-feeding. Do not breast-feed for 24 hours after getting this drug.
- If the patient is a child. This drug is not approved for use in children.
- If your child or teenager has or is getting better from flu signs, chickenpox, or other viral infections. The risk of a very bad problem called Reye’s syndrome may be raised. Do not give this drug to a child or teenager who has or is getting better from a viral infection.
This is not a list of all drugs or health problems that interact with this drug.
Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take this drug with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.
What are some things I need to know or do while I take this drug?
- Tell all of your health care providers that you take this drug. This includes your doctors, nurses, pharmacists, and dentists.
- Avoid alcohol and products that have alcohol or propylene glycol in them while taking this drug and for at least 72 hours after your last dose. Drinking alcohol or taking products that have alcohol or propylene glycol in them, like some cough syrups, may cause stomach cramps, upset stomach or throwing up, headaches, and flushing.
- You may get sunburned more easily. Avoid sun, sunlamps, and tanning beds. Use sunscreen and wear clothing and eyewear that protects you from the sun.
- Do not use longer than you have been told. A second infection may happen.
- This drug may affect certain lab tests. Tell all of your health care providers and lab workers that you take this drug.
- This drug may raise the chance of a severe brain problem called aseptic meningitis. Call your doctor right away if you have a headache, fever, chills, very upset stomach or throwing up, stiff neck, rash, bright lights bother your eyes, feeling sleepy, or feeling confused.
- This drug may cause a change in tooth color to yellow-gray-brown in children younger than 8 years old. If this change of tooth color happens, it will not go away. Talk with the doctor.
- Birth control pills and other hormone-based birth control may not work as well to prevent pregnancy. Use some other kind of birth control also like a condom when taking this drug.
- This drug may cause harm to the unborn baby if you take it while you are pregnant. If you are pregnant or you get pregnant while taking this drug, call your doctor right away.
What are some side effects that I need to call my doctor about right away?
WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:
- Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
- Vaginal itching or discharge.
- Fast or abnormal heartbeat.
- Nervous system problems have happened with this drug. Some people who took this drug for a long time have had nerve problems that lasted for a long time. Call your doctor right away if you have a burning, numbness, or tingling feeling that is not normal; change in balance or eyesight; dizziness or passing out; headache; not able to sleep; seizures; or trouble speaking. Call your doctor right away if you feel confused, depressed, irritable, tired, or weak.
- Raised pressure in the brain has happened with this drug. Most of the time, this will go back to normal after this drug is stopped. Sometimes, loss of eyesight may happen and may not go away even after this drug is stopped. Call your doctor right away if you have a headache or eyesight problems like blurred eyesight, seeing double, or loss of eyesight.
- Low white blood cell counts have happened with this drug. This may lead to a higher chance of getting an infection. Call your doctor right away if you have signs of infection like fever, chills, or sore throat.
- Severe skin reactions may happen with this drug. These include Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other serious reactions. Sometimes, body organs may also be affected. These reactions can be deadly. Get medical help right away if you have signs like red, swollen, blistered, or peeling skin; red or irritated eyes; sores in your mouth, throat, nose, eyes, genitals, or any areas of skin; fever; chills; body aches; shortness of breath; or swollen glands.
What are some other side effects of this drug?
All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:
- Upset stomach.
- Stomach pain or diarrhea.
- Dark tongue and stool. This is normal and not harmful.
These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to your national health agency.
You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.
How is this drug best taken?
Use this drug as ordered by your doctor. Read all information given to you. Follow all instructions closely.
- Take this drug with meals and at bedtime or as you have been told by your doctor.
- Chew bismuth tablets.
- Swallow metronidazole tablets and tetracycline capsules whole. Do not chew, break, or crush.
- Take with a full glass of water.
- Do not take products that have iron, zinc, or sodium bicarbonate in them or products like antacids that have aluminum, calcium, or magnesium in them at the same time as this drug. Talk with your doctor or pharmacist.
- Do not eat or drink dairy products or take calcium at the same time as this drug. They may make this drug not work as well. If you have questions, talk with your doctor or pharmacist.
- Keep taking this drug as you have been told by your doctor or other health care provider, even if you feel well.
What do I do if I miss a dose?
- Skip the missed dose and go back to your normal time.
- Do not take 2 doses at the same time or extra doses.
- If you miss 4 doses, call your doctor.
How do I store and/or throw out this drug?
- Store at room temperature in a dry place. Do not store in a bathroom.
- Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
- Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.
General drug facts
- If your symptoms or health problems do not get better or if they become worse, call your doctor.
- Do not share your drugs with others and do not take anyone else’s drugs.
- Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your doctor, nurse, pharmacist, or other health care provider.
- Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about this drug, please talk with your doctor, nurse, pharmacist, or other health care provider.
- If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.
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