Metronidazole (Flagyl): Uses, Dosage, Side Effects & Savings
Metronidazole is a unique antibiotic that also works against certain parasites. It is the go-to treatment for bacterial vaginosis, trichomoniasis, C. difficile, and dental infections. Here is the complete guide.
Need a Metronidazole Prescription?
BV, trich, dental infections — a telehealth provider can evaluate your symptoms and send a prescription today.
What Is Metronidazole?
Metronidazole is an antibiotic and antiprotozoal agent that works by entering bacterial and protozoal cells and damaging their DNA, preventing reproduction and causing cell death. It is specifically effective against anaerobic organisms — those that live without oxygen — and certain protozoa (single-celled parasites).
It comes as oral tablets (250 mg, 500 mg), an IV formulation, a topical gel (MetroGel) for rosacea, and a vaginal gel (MetroGel Vaginal) for BV.
What Does Metronidazole Treat?
| Condition | Typical Regimen | Notes |
|---|---|---|
| Bacterial vaginosis (BV) | 500 mg twice daily x 7 days, or vaginal gel 5 days | First-line treatment; partner treatment not routinely required |
| Trichomoniasis (STI) | 2 g single dose OR 500 mg twice daily x 7 days | Treat sexual partner simultaneously |
| C. difficile colitis | 500 mg three times daily x 10–14 days | Alternative to vancomycin for mild cases |
| Dental infections / abscess | 500 mg three times daily x 5–7 days | Often combined with amoxicillin |
| H. pylori (peptic ulcer) | Part of triple or quadruple therapy | Combined with PPI + clarithromycin or bismuth |
| Pelvic inflammatory disease (PID) | Combined therapy | Used alongside other antibiotics |
| Giardiasis / amebiasis | 250–750 mg three times daily x 5–10 days | Treats intestinal parasites |
| Rosacea (topical) | MetroGel 1% applied daily | Reduces inflammation and papules |
The Alcohol Interaction — Very Important
🚨 Do NOT drink alcohol while taking metronidazole
Metronidazole blocks an enzyme called acetaldehyde dehydrogenase, which breaks down alcohol. When you drink on metronidazole, acetaldehyde builds up rapidly, causing a severe disulfiram-like reaction:
- Flushing, rapid heartbeat, throbbing headache
- Severe nausea and vomiting
- Low blood pressure, dizziness
Avoid all alcohol — including mouthwash, cough syrups, and cooking wine — for the entire course AND for at least 48–72 hours after your last dose.
Side Effects
- Nausea, metallic taste in mouth — very common; take with food
- Vomiting, diarrhea, stomach cramps
- Headache, dizziness
- Dark or discolored urine — harmless; caused by drug metabolites
- Numbness or tingling in hands/feet — report to your provider; may indicate peripheral neuropathy
- Yeast infections
Frequently Asked Questions
How do I know if I have BV vs. a yeast infection?
BV typically causes a thin, grayish-white discharge with a strong "fishy" odor, particularly after sex. Yeast infections cause thick, white, cottage-cheese-like discharge with intense itching. BV is treated with metronidazole; yeast infections are treated with antifungals like fluconazole. A telehealth provider can help determine which you have based on your symptoms.
Can I get metronidazole online without an in-person visit?
Yes. BV, trichomoniasis, and dental infections are commonly diagnosed and treated via telehealth. A provider will ask detailed questions about your symptoms and medical history. A single 2 g dose for trichomoniasis can often be prescribed after a brief consultation, and many telehealth platforms partner with mail-order pharmacies for fast delivery.
What is the metallic taste from metronidazole?
A bitter, metallic taste is one of the most commonly reported side effects of metronidazole — some patients describe it as "coppery" or "like pennies in your mouth." It is caused by the drug being secreted in saliva. Chewing sugar-free gum, sucking on hard candy, and brushing your teeth after each dose can help reduce it. It goes away completely when you finish the course.
How much does metronidazole cost without insurance?
Generic metronidazole is very affordable — typically $4–$12 for a 7-day course with a free discount card. The vaginal gel form costs more, around $15–$30. See current prices near you at /drug/metronidazole.
Does my partner need to be treated for BV?
Routine treatment of male partners is not recommended for BV — studies show it does not reduce recurrence rates. However, for trichomoniasis, it is essential that both partners be treated at the same time to prevent passing the infection back and forth. Female partners of women with BV may benefit from treatment.
Is metronidazole safe during pregnancy?
Metronidazole is used in pregnancy for BV and trichomoniasis — untreated BV in pregnancy can lead to preterm labor and low birth weight, so the benefits of treatment typically outweigh any theoretical risk. It has a long history of use in pregnancy. Most guidelines consider it safe in the second and third trimesters; discuss the timing with your provider for first-trimester use.
Get a Metronidazole Prescription Online
BV, trichomoniasis, and dental infections can be evaluated via telehealth — no waiting room needed.