Table of ContentsView AllTable of ContentsHow Long Does Metronidazole Last?What Is Metronidazole Used For?Side EffectsWhat Precautions Should I Consider for Metronidazole?
Table of ContentsView All
View All
Table of Contents
How Long Does Metronidazole Last?
What Is Metronidazole Used For?
Side Effects
What Precautions Should I Consider for Metronidazole?
Metronidazole is an antibiotic commonly used to treat different types of infections. It can be taken anywhere from once per day (if you take an extended-release formulation) to up to four times per day, or every six hours. Common brand name products include Flagyl and Metrogel.
One dose of metronidazole will stay in your system for around 40 to 56 hours, or approximately two days. After two days, the amount of metronidazole remaining after just one dose will be negligible and no longer effective. This is why it must be taken more often than every other day to keep the concentration in your blood high enough to continue treating the infection.
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Half-lives of drugs are used to help determine dosing schedules. Metronidazole is typically dosed between two and four times per day, or around every 6 to 12 hours.
Dosing depends on what type of bacteria is causing the infection and where the infection is in the body.Certain bacteria or locations in the body may require higher or lower concentrations of metronidazole for effective treatment, meaning you need to keep taking the drug fairly often to remain at or above that blood concentration.
Some common approved indications for metronidazole include:
More common side effects of metronidazole include:
Less common side effects include:
Be sure your healthcare provider is aware of your full medical history to provide the most optimal antibiotic and dose to treat your infection. They should be aware if you:
Interactions
There are a few important drug interactions you should be aware of when you start taking metronidazole:
Be sure all of your healthcare providers and your pharmacist are aware of your full medication list so they can best advise you on how to avoid drug interactions or make necessary dose adjustments.
Is There an Interaction Between Metronidazole and Alcohol?
Data on the presence of disulfiram-like reactions with metronidazole is conflicting and not definitive, but the possibility of a reaction is included in the manufacturer’s labeling, so it is best to avoid alcohol.
Consuming alcohol while taking metronidazole can lead to a severe reaction that causes nausea, vomiting, flushing, headache, and increased heart rate.
Wait at least three days after you take your last prescribed dose of metronidazole before drinking alcohol to make sure that the antibiotic is sufficiently cleared from your body and will not cause this disulfiram-like reaction.
Summary
Metronidazole is an important antibiotic used to treat many different types of infections. It’s best to wait until at least three days after your last dose of metronidazole before consuming alcohol, as this will give your body the time it needs to clear the drug almost completely from your body.
As with any antibiotic, complete your entire course as prescribed, even if you feel better before it’s finished. Stopping the medication before your course ends can cause the infection to return and contribute to antibiotic resistance.
5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
FDA.Metronidazole prescribing information.
Drugs and Lactation Database (LactMed®) [Internet]. Bethesda (MD): National Institute of Child Health and Human Development; 2006–.Metronidazole.
Hernández Ceruelos A, Romero-Quezada LC, Ruvalcaba Ledezma JC, López Contreras L.Therapeutic uses of metronidazole and its side effects: an update.Eur Rev Med Pharmacol Sci. 2019;23(1):397-401. doi:10.26355/eurrev_201901_16788
Shin J, Wi YM, Lee YJ.Metronidazole therapy as initial treatment of Clostridium difficile infection in patients with chronic kidney disease in Korea.Epidemiol Infect. 2019;147:e289. doi:10.1017/S0950268819001742
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