Metronidazole (systemic): Patient drug information

Warning

Metronidazole has been shown to cause cancer in mice and rats with long-term use. Talk with the doctor.
The doctor has given you this drug for a certain health problem. Do not use this drug for other health problems.

What is this drug used for?

It is used to treat infections.
It is used to prevent infections during bowel surgery.
It may be given to you for other reasons. Talk with the doctor.

What do I need to tell my doctor BEFORE I take 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 taken disulfiram within the past 2 weeks.
If you are less than 12 weeks pregnant. This drug is not for use in certain patients who are less than 12 weeks pregnant.
If you are breast-feeding. Do not breast-feed for 24 hours after getting this drug.
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.
Have blood work checked as you have been told by the doctor. Talk with the doctor.
This drug may affect certain lab tests. Tell all of your health care providers and lab workers that you take this drug.
If you are on dialysis, talk with your doctor.
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.
Do not use longer than you have been told. A second infection may happen.
If you are on a low-sodium or sodium-free diet, talk with your doctor. Some of these products have sodium.
If you are 65 or older, use this drug with care. You could have more side effects.
Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using this drug while you are pregnant.

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.
Signs of a very bad skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis) like red, swollen, blistered, or peeling skin (with or without fever); red or irritated eyes; or sores in the mouth, throat, nose, or eyes.
Redness or white patches in mouth or throat.
Vaginal itching or discharge.
Fast or abnormal heartbeat.
Pain when passing urine or blood in urine.
Passing urine more often.
Pelvic pain.
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.
This drug may raise the chance of a very bad 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.
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.

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:
All products:
Constipation, diarrhea, stomach pain, upset stomach, throwing up, or decreased appetite.
Stomach cramps.
Metallic taste.
Headache.
Joint pain.
Lowered interest in sex.
Infusion:
Irritation where this drug is given.
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.

How is this drug best taken?

Use this drug as ordered by your doctor. Read all information given to you. Follow all instructions closely.
Tablets and capsules:
Take with or without food. Take with food if it causes an upset stomach.
Keep taking this drug as you have been told by your doctor or other health care provider, even if you feel well.
Infusion:
It is given as an infusion into a vein over a period of time.

What do I do if I miss a dose?

All oral products:
Take a missed dose as soon as you think about it.
If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
Do not take 2 doses at the same time or extra doses.
Infusion:
Call your doctor to find out what to do.

How do I store and/or throw out this drug?

All oral products:
Store at room temperature protected from light. Store in a dry place. Do not store in a bathroom.
Infusion:
If you need to store this drug at home, talk with your doctor, nurse, or pharmacist about how to store it.
All products:
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.
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.

Consumer Information Use and Disclaimer

This generalized information is a limited summary of diagnosis, treatment, and/or medication information. It is not meant to be comprehensive and should be used as a tool to help the user understand and/or assess potential diagnostic and treatment options. It does NOT include all information about conditions, treatments, medications, side effects, or risks that may apply to a specific patient. It is not intended to be medical advice or a substitute for the medical advice, diagnosis, or treatment of a health care provider based on the health care provider's examination and assessment of a patient's specific and unique circumstances. Patients must speak with a health care provider for complete information about their health, medical questions, and treatment options, including any risks or benefits regarding use of medications. This information does not endorse any treatments or medications as safe, effective, or approved for treating a specific patient. UpToDate, Inc. and its affiliates disclaim any warranty or liability relating to this information or the use thereof. The use of this information is governed by the Terms of Use, available at https://www.wolterskluwer.com/en/know/clinical-effectiveness-terms.