If you’ve searched for metronidasool, you’re in good company. Plenty of people type it this way because it’s how the word sounds. The correct spelling is metronidazole, but whichever way you spell it, you’re asking about the same well-established antibiotic and antiprotozoal medicine, sold under brand names like Flagyl and Metrogyl. Here’s a plain-language guide to what metronidasool is, what it treats, and what to keep in mind before you take it.
Table of Contents
What Is Metronidasool?
Metronidasool belongs to a group of medicines called nitroimidazole antimicrobials. It works by stopping the growth of anaerobic bacteria (bacteria that live without oxygen) and certain parasites. That narrow focus is why doctors prescribe it for specific infections rather than as an all-purpose antibiotic. Like every antibiotic, it won’t help with colds, flu, or other viral infections.
It’s been in clinical use since 1960, when it was first sold commercially in France, and it’s on the World Health Organization’s List of Essential Medicines. You can get it as tablets, capsules, or a liquid suspension, as a cream or gel for the skin, and as an intravenous infusion in hospitals. In the U.S. alone, it was prescribed more than two million times in 2023.
What Is Metronidasool Used For?
Doctors turn to metronidasool for a fairly wide range of problems. The best-known are bacterial vaginosis, trichomoniasis (a sexually transmitted infection), and pelvic inflammatory disease, where it’s usually combined with another antibiotic. It also treats parasitic infections of the gut, such as giardiasis and amebiasis, and it’s an option for some cases of C. difficile colitis, although current guidelines often favor vancomycin or fidaxomicin first.
It’s also used for anaerobic infections of the lungs, abdomen, and mouth, sometimes to prevent infection after surgery, and alongside other medicines to clear Helicobacter pylori. In gel or cream form, metronidasool is a familiar treatment for rosacea and perioral dermatitis.
The right form, dose, and length of treatment depend on the infection, so follow your own prescription label rather than anything you read online.
How to Take Metronidasool Properly
Take it exactly as prescribed. If you’re using the liquid, shake it well and measure it with a dosing spoon, oral syringe, or measuring cup, because a kitchen spoon can give you the wrong amount.
The most common mistake is stopping once you feel better. Please don’t. Finishing the whole course gives the infection the best chance of being cleared, and stopping early can let bacteria survive and become resistant. If you miss a dose, take it when you remember, unless the next one is almost due. In that case, skip it and carry on. Never double up.
Common Side Effects of Metronidasool
Most people who have trouble with it notice something mild: nausea, vomiting, diarrhea, an upset stomach, a lower appetite, headaches, or a dry mouth. Many also describe a sharp metallic taste, sometimes with a furry or irritated tongue. It’s unpleasant but usually isn’t a sign that something is wrong. Tell your doctor if symptoms get severe or won’t go away.
A few reactions need a call to your doctor right away. These include numbness, tingling, or burning in the hands or feet, seizures, confusion, dizziness, trouble with coordination or speech, and skin reactions such as rash, hives, peeling, or blistering. Mouth sores, facial swelling, or signs of a new infection like fever and sore throat also deserve prompt attention. Higher doses and longer treatment raise the risk of nerve and central nervous system problems, which is one reason metronidasool should only be used when it’s truly needed.
Metronidasool and Alcohol
This is the warning most people have heard, and it’s a real one. Drinking alcohol on metronidasool can cause nausea, vomiting, stomach cramps, headache, sweating, and flushing. The same goes for products containing propylene glycol, which shows up in some medicines, foods, and e-cigarette liquids. The usual advice is to avoid both during treatment and for at least three days after your last dose. Some sources give a shorter window, but the safest route is the longer one, or ask your pharmacist.
Metronidasool in Pregnancy and Breastfeeding
If you’re pregnant or planning to be, tell your doctor before starting metronidasool. It’s generally avoided in the first trimester, and guidance for later months varies, so the decision rests on weighing benefits against risks with your healthcare provider. If you become pregnant while taking it, call your doctor.
It also passes into breast milk and is generally considered incompatible with breastfeeding. Your doctor may suggest pumping and discarding your milk during treatment and for 48 hours after your final dose. Talk through feeding options so you have a plan that works for you and your baby.
Drug Interactions and Who Should Be Careful
Metronidasool can interact with other medicines. Disulfiram is one to watch, so mention it if you’ve taken it in the past two weeks. It can also affect how the body handles warfarin, and cimetidine may interact with it too. The simplest habit is to keep a current list of everything you take, including over-the-counter medicines, vitamins, and supplements, and share it with your doctor and pharmacist.
Also mention any history of Crohn’s disease, blood problems, kidney or liver disease, or conditions affecting the brain. People with Cockayne syndrome, a rare genetic disorder, are usually advised not to take it, and anyone allergic to it or similar medicines should say so.
The Cancer Warning, Explained Calmly
You may notice that metronidasool carries a cancer warning. It comes from laboratory studies in which the drug caused tumors in animals, and in 2016 the U.S. National Toxicology Program listed it as reasonably anticipated to be a human carcinogen. In people, though, the evidence is far less clear. Some studies found no increased risk, and the link remains uncertain. The practical takeaway is that it isn’t a medicine for casual or extended use. It’s meant for real infections, prescribed by someone who has weighed the benefits and risks.
Storage, Overdose, and Practical Reminders
Keep metronidasool in its original container, tightly closed, at room temperature, away from light, heat, and moisture (so not in the bathroom), and out of children’s reach. Don’t share your prescription. For leftovers, use a medicine take-back program rather than flushing them.
If someone takes too much, call poison control right away (1-800-222-1222 in the U.S.). If the person has collapsed, had a seizure, or has trouble breathing, call emergency services immediately. Before any lab test, tell the staff you’re taking it, and keep your follow-up appointments.
Why “Metronidasool” Is Such a Common Spelling
Many people search by sound, and metronidazole isn’t an easy word to spell from memory. That’s why “metronidasool” gets typed so often. It’s harmless, but it’s a good reminder to double-check what you read about any medication. Lean on your pharmacist, the leaflet that comes with your prescription, or an established reference like MedlinePlus rather than a page built around a typo.
Frequently Asked Questions About Metronidasool
Is metronidasool a real medication?
Not under that spelling. Metronidasool is a common misspelling of metronidazole, the antibiotic and antiprotozoal drug also sold as Flagyl.
What does metronidasool treat?
It treats bacterial vaginosis, trichomoniasis, pelvic inflammatory disease, giardiasis, amebiasis, and several anaerobic bacterial infections. Topical forms are also used for rosacea.
Can I drink alcohol while taking metronidasool?
No. Avoid alcohol during treatment and for at least three days afterward, since mixing the two can cause cramps, nausea, vomiting, headache, and flushing.
Is metronidasool safe during pregnancy?
It’s generally avoided in the first trimester. Later in pregnancy it depends on the situation, so talk with your healthcare provider first.
Should I finish the whole course even if I feel better?
Yes. Stopping early can leave the infection partly treated and may encourage antibiotic resistance.
The Bottom Line on Metronidasool
Metronidasool is simply metronidazole with a phonetic spelling: an old, trusted medicine that works well for the right infections, as long as you respect the essentials. Skip the alcohol, tell your doctor about your other medications and any pregnancy or breastfeeding plans, finish the course, and speak up if something feels off. For anything specific to your health, your doctor or pharmacist is always the best source.