Common Brand Name(s): Flagyl
Important: How To Use This Information
This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Metronidazole is an antibiotic that is used to treat a wide variety of infections. It may also be used to prevent infection after bowel surgery. It works by stopping the growth of certain bacteria and parasites.
How To Use
This medication is given by injection into a vein as directed by your doctor, usually 3 or 4 times a day. It is injected slowly into a vein over 1 hour. The dosage is based on your medical condition and response to treatment.
If you are using this medication at home, learn all preparation and usage instructions from your health care professional. Before using, check this product visually for particles or discoloration. If either is present, do not use the liquid. Learn how to store and discard medical supplies safely.
For the best effect, use this antibiotic at evenly spaced times. To help you remember, use this medication at the same time(s) every day.
Continue to use this medication for the full time prescribed, even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the infection.
Tell your doctor if your condition lasts or gets worse.
Dizziness, headache, stomach upset, nausea, vomiting, loss of appetite, diarrhea, constipation, or metallic taste in your mouth may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.
This medication may cause your urine to turn darker in color. This effect is harmless and will disappear when the medication is stopped.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if you have any serious side effects, including:
- signs of a new infection (such as sore throat that doesn't go away, fever)
- easy bruising/bleeding
- stomach/abdominal pain
- painful urination
Get medical help right away if you have any very serious side effects, including:
- mental/mood changes (such as confusion)
- trouble speaking
- numbness/tingling of arms/legs
- eye pain
- sudden vision changes
- headache that is severe or doesn't go away
- stiff/painful neck
Use of this medication for prolonged or repeated periods may result in oral thrush or a new yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:
- itching/swelling (especially of the face/tongue/throat)
- severe dizziness
- trouble breathing
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Before using metronidazole, tell your doctor or pharmacist if you are allergic to it; or to other antibiotics (such as tinidazole); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of:
- liver disease
- kidney disease
- certain blood disorders (low blood cell counts)
- swelling (edema)
People with a rare genetic disorder (Cockayne syndrome) may be at risk for very serious liver disease if they use metronidazole. Discuss the risks and benefits with your doctor. If metronidazole is used, your doctor will check your liver function. Get medical help right away if you have any signs of liver disease during treatment (such as nausea/vomiting that doesn't stop, loss of appetite, severe stomach/abdominal pain, yellowing eyes/skin, dark urine).
Avoid alcoholic beverages and products containing propylene glycol while taking this medication and for at least 3 days after finishing this medicine because severe stomach upset/cramps, nausea, vomiting, headache, and flushing may occur.
This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Talk to your doctor if you are using marijuana (cannabis).
This medication contains sodium. Consult your doctor or pharmacist if you are on a salt-restricted diet or if you have a condition that could be worsened by an increase in salt intake (such as congestive heart failure, edema).
Metronidazole may cause live bacterial vaccines (such as typhoid vaccine) to not work as well. Do not have any immunizations/vaccinations while using this medication unless your doctor tells you to.
Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.
This medication passes into breast milk. Discuss the risks and benefits with your doctor before breast-feeding.
See also Precautions section.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Some products that may interact with this drug include:
- alcohol-containing products (such as cough and cold syrups, aftershave)
- products containing propylene glycol
- lopinavir/ritonavir solution
Do not use metronidazole if you are also taking disulfiram or if you have taken disulfiram within the last 2 weeks.
This medication may interfere with certain lab tests, possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: nausea, vomiting, unsteadiness.
If you are using this medication for a longer time, lab tests (such as blood cell counts) may be done while you are using this medication. Keep all medical and lab appointments. Consult your doctor for more details.
For the best possible benefit, it is important to receive each scheduled dose of this medication as directed. If you miss a dose, contact your doctor or pharmacist right away to establish a new dosing schedule. Do not double the dose to catch up.
Consult the product instructions and your pharmacist for storage details. Keep all medications away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised January 2020.
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Conditions of use: The information in this database is intended to supplement, not substitute for the expertise and judgment of healthcare professionals. The information in not intend to cover all possible uses, directions, precautions, drug interactions or adverse effects nor should it be construed in indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.