Buy Metronidazole (Flagyl) — Online Prescription
Metronidazole (Flagyl) is the go-to prescription for bacterial vaginosis and trichomoniasis, and it also treats gut parasites, some serious infections and, as a gel or cream, rosacea. Here's the dosage for each use, how the pill compares with the vaginal gel, the side effects people actually notice, what the evidence says about alcohol, and what a course costs.
Medically reviewed Medically reviewed by Sabrina Griswold, Pharm.D. — NPI 1821451063 · Last updated 2026-10-23
| Active ingredient | Metronidazole |
|---|---|
| Dosage form | Oral tablet (250, 500 mg) and capsule (375 mg), topical gel/cream/lotion, vaginal gel, IV injection |
| Administration route | Oral, topical, vaginal, intravenous |
Class: Nitroimidazole Antimicrobial [EPC]
Indications: INDICATIONS AND USAGE Symptomatic Trichomoniasis. Metronidazole tablets are indicated for the treatment of T. vaginalis infection in females and males when the presence of the trichomonad has been confirmed by appropriate laboratory procedures (wet smears and/or cultures). Asymptomatic Trichomoniasis. Metronidazole tablets are indicated in the treatment of asymptomatic T. vaginalis infection in females when the organism is associated with endocervicitis, cervicitis, or cervical erosion. Since th…
Boxed warning: WARNING Metronidazole has been shown to be carcinogenic in mice and rats (see PRECAUTIONS ). Unnecessary use of the drug should be avoided. Its use should be reserved for the conditions described in the INDICATIONS AND USAGE section below.
Contraindications: CONTRAINDICATIONS Hypersensitivity Metronidazole tablet are contraindicated in patients with a prior history of hypersensitivity to metronidazole or other nitroimidazole derivatives. In patients with trichomoniasis, metronidazole tablet are contraindicated during the first trimester of pregnancy (see PRECAUTIONS ). Psychotic Reaction with Disulfiram Use of oral metronidazole is associated with psychotic reactions in alcoholic patients who were using disulfiram concurrently. Do not administer met…
openFDA label data — Updated 2026-10-01Metronidazole (Flagyl) is a prescription antibiotic and antiparasitic. Its most common use is bacterial vaginosis and trichomoniasis: 500 mg twice a day for 7 days, the CDC's first-line regimen for both in women (men with trich usually take one 2 g dose). It also treats amebiasis, giardiasis and serious anaerobic infections, while the gel or cream treats rosacea and the vaginal gel treats BV. Expect a metallic taste or nausea. A yeast infection afterward is common. The label says no alcohol during treatment and for 3 days after, though the CDC now calls that unnecessary. A generic 7-day course costs pharmacies under $2.
What metronidazole is used for
The oral, topical and vaginal forms share an active ingredient but treat completely different problems. Make sure the product you have matches what your prescriber intended.
| Form | What it treats |
|---|---|
| Oral tablet or capsule | Trichomoniasis (FDA-approved, confirmed by lab test) · bacterial vaginosis (CDC first-line) · intestinal amebiasis and amebic liver abscess · serious anaerobic infections (abdominal, skin, gynecologic, bone, blood) · giardiasis (off-label, listed by the CDC as effective) · mild C. difficile colitis when vancomycin or fidaxomicin isn't available (IDSA 2021). Worm infections such as strongyloidiasis need a different drug, ivermectin. |
| Topical gel, cream or lotion (face) | The bumps and redness of rosacea, not the flushing itself |
| Vaginal gel | Bacterial vaginosis |
| IV injection | Serious anaerobic infections in the hospital |
What it doesn't treat: ordinary UTIs, yeast infections, colds, strep throat or most skin infections. Metronidazole only works on anaerobic bacteria (ones that live without oxygen) and certain parasites.
Metronidazole dosage chart
Adult doses from the FDA labels and current US guidelines. Your prescriber sets your exact dose and length.
| Condition | Typical adult regimen | Source |
|---|---|---|
| Bacterial vaginosis | 500 mg by mouth twice a day for 7 days, or vaginal gel 0.75%, one applicator (5 g) once a day for 5 days | CDC 2021 |
| Trichomoniasis, women | 500 mg twice a day for 7 days | CDC 2021 |
| Trichomoniasis, men | 2 g as a single dose (four 500 mg tablets) | CDC 2021 |
| Trichomoniasis, label options | 2 g once (or 1 g twice in one day), or 250 mg three times a day for 7 days; sex partners treated at the same time | FDA label |
| Amebiasis (amebic dysentery, liver abscess) | 750 mg three times a day for 5–10 days | FDA label |
| Serious anaerobic infections | Usually IV first, then 7.5 mg/kg every 6 hours (about 500 mg for a 70 kg adult) for 7–10 days or longer. Maximum 4 g in 24 hours. | FDA label |
| C. difficile, non-severe | 500 mg three times a day for 10 days, only if vancomycin and fidaxomicin aren't available | IDSA/SHEA 2021 |
| Giardiasis | Off-label; dose and length set by your prescriber | CDC |
| Rosacea | Thin layer of 0.75% or 1% gel, cream or lotion once or twice a day, depending on the product | Product labels |
- "500 mg twice a day for 7 days" is 14 tablets. Space doses about 12 hours apart. Food doesn't change how much you absorb, and taking it with a meal can ease nausea.
- Severe liver disease (Child-Pugh C) lowers the dose: the label halves it for amebiasis and drops trichomoniasis to once a day.
- Dialysis removes metronidazole, so a dose may be added after a session.
- Repeat courses for trichomoniasis should be 4–6 weeks apart, with the infection reconfirmed by lab test first (label).
Metronidazole for BV: pill or gel?
Both are CDC first-line choices for bacterial vaginosis, alongside clindamycin cream. They work about equally. The difference is how you'd rather take it:
Metronidazole tablets
- Regimen
- 500 mg twice a day for 7 days
- Good for
- No mess; also covers trichomoniasis if you're tested for both
- Trade-off
- More nausea and metallic taste, since the drug goes through your whole body
- Cost
- Cheapest option: generic tablets cost pharmacies about $0.10 each
Metronidazole gel 0.75%
- Regimen
- One full applicator (5 g) at bedtime for 5 days
- Good for
- Fewer whole-body side effects; shorter course
- Trade-off
- Discharge (12% in trials) and yeast infections (10%); it can be messy
- Cost
- Generic gel is more than the tablets but usually still modest
- Bedtime, for the gel: the label says to apply once-daily gel at bedtime, so it stays in place.
- Skip douching. The CDC says douching may make BV come back and doesn't help treat it.
- Use condoms or avoid sex during treatment (CDC). With trichomoniasis, partners must be treated too, or you can be reinfected.
- BV keeps coming back? That's common. Ask your prescriber about a longer suppressive course rather than repeating the same 7 days.
Side effects and how long they last
Expect some of these
- A sharp, metallic taste, which the label says "is not unusual"
- Nausea, sometimes with headache or loss of appetite
- Diarrhea, stomach cramps or constipation
- Vaginal yeast infection (itching, thick white discharge)
- Darker urine, which is rare (about 1 in 100,000) and harmless
Nerve or skin warning signs
- Numbness, tingling or burning in your hands or feet
- Dizziness, unsteady walking or slurred speech
- Vision changes
- A new rash or itching
Rare but serious
- A seizure
- Confusion, severe headache with stiff neck or fever
- Blistering or peeling skin, or mouth sores
- Swelling of the face or throat, or trouble breathing
How long they last: metronidazole's half-life is about 8 hours, so most of it is cleared about 2 days after your last dose, and taste changes and nausea usually fade with it. Nerve effects are rare and mostly linked to long or repeated courses. The label says they're generally reversible "within days to weeks" after stopping. People with Cockayne syndrome (a rare genetic disorder) must not take metronidazole because of reports of fatal liver failure.
The label's boxed warning notes that metronidazole caused cancer in mice and rats in long-term studies. That's why it's reserved for the infections it's approved for, rather than used casually.
Metronidazole and alcohol: label vs. CDC
This is one of the few places where the official sources disagree:
Avoid it
- Rule
- No alcohol, and no products with propylene glycol, during treatment and for at least 3 days after
- Why
- Reports of cramps, nausea, vomiting, headache and flushing, called a "disulfiram-like" reaction
Not necessary
- Finding
- No lab, animal or clinical studies give convincing evidence of a true disulfiram-like interaction
- Why
- Old reports could have been alcohol alone or metronidazole's own side effects; it doesn't block the enzyme disulfiram blocks
A 2023 case-control study points the same way as the CDC. Our practical take: the course is short, so skipping alcohol for it and the 3 days after costs little and avoids a bad night, especially since alcohol worsens the nausea metronidazole already causes. If your prescriber follows the CDC view and says a drink is fine, that's a reasonable, evidence-based call.
Drug interactions
From the Flagyl label. Tell your pharmacist about everything you take, including OTC products.
| Taken with | What can happen |
|---|---|
| Disulfiram (Antabuse) | Psychotic reactions. Don't take metronidazole within 2 weeks of disulfiram. |
| Warfarin and similar blood thinners | Stronger blood-thinning effect. INR needs close monitoring. |
| Lithium | Lithium levels can rise to toxic. Levels are checked a few days in. |
| Busulfan | Much higher busulfan levels. Avoided unless there's no alternative. |
| Drugs that prolong the QT interval | Higher risk of heart-rhythm problems |
| Cimetidine | Metronidazole lasts longer in the body |
| Phenytoin, phenobarbital | Metronidazole is cleared faster; phenytoin levels can rise |
| Alcohol, propylene glycol products | See the alcohol section above |
Pregnancy and breastfeeding
- First trimester: the label contraindicates metronidazole for trichomoniasis in the first trimester, and says the single 2 g dose shouldn't be used later in pregnancy either, since it produces higher blood levels.
- Later in pregnancy: studies including more than 5,000 exposed pregnancies mostly found no increase in birth defects or other harm (label), and the CDC uses metronidazole for BV and trichomoniasis in pregnancy. Your OB weighs it against the risks of the untreated infection.
- Breastfeeding: metronidazole reaches breast milk at about the same level as in the blood. The label offers the option to pump and discard during treatment and for 48 hours after the last dose.
Price and filling your prescription
Generic metronidazole is cheap. At CMS's NADAC pharmacy cost of about $0.10 per 500 mg tablet, a 7-day, 14-tablet BV course costs a pharmacy about $1.50, and a single 2 g trichomoniasis dose about $0.42. Brand Flagyl is rarely stocked. Your cash price will be higher than the pharmacy's cost but is often lower than an insurance copay, so ask.
- Right form matters. Oral, topical and vaginal products aren't interchangeable. We fill exactly what your prescriber ordered.
- Fast fills. Have your prescriber send it to Arrow Pharmacy or call (860) 522-9289. We'll have it ready quickly, with free delivery in the Hartford area.
- Partner treatment: for trichomoniasis, partners need their own prescription. Ask your prescriber about treating both of you at once.
For what you can and can't get without a prescription, and how other common antibiotics compare, see over-the-counter antibiotics and amoxicillin vs. azithromycin.
Shortage reported — Affects: Metronidazole in Flexible Container, Injection, 500 mg/100 mL (NDC 0409-0152-24). If that's not the form or strength you take, ask your pharmacist whether your specific product is affected.
FDA openFDA — Updated 2026-11-01National Average Drug Acquisition Cost (NADAC): $0.104 per tablet (METRONIDAZOLE 500 MG TABLET). This is the average price pharmacies pay wholesalers — not your out-of-pocket cost — published by CMS for pricing transparency.
CMS NADAC — Updated 2026-11-01Metronidazole Prices in the USA
| Dosage | Brand-name avg. price | Generic avg. price |
|---|---|---|
| 250 mg tablet (14-day course) | $120–200 (Flagyl, rarely stocked) | $10–22 |
| 500 mg tablet (7–10 day course) | $150–250 (Flagyl, rarely stocked) | $12–28 |
| Topical gel/cream 0.75%–1% (rosacea, per tube) | $150–220 (MetroGel/Noritate) | $20–45 |
| Vaginal gel 0.75% (per course) | $90–150 (Metrogel-Vaginal) | $20–40 |
Frequently asked questions
What is metronidazole 500 mg used for?
Most often for bacterial vaginosis (BV) and trichomoniasis: the CDC's first-choice regimen for both in women is 500 mg twice a day for 7 days. Men with trichomoniasis usually take a single 2 g dose (four 500 mg tablets). The same tablets also treat intestinal amebiasis, giardiasis (off-label), serious anaerobic infections and, as a back-up option, mild C. difficile colitis.
Can I buy metronidazole over the counter?
No. Metronidazole requires a prescription in the United States in every approved form: tablets and capsules, topical gel or cream, vaginal gel and injection. A clinician needs to confirm the diagnosis first (trichomoniasis, for example, is confirmed by lab testing). Once you have a prescription, generic metronidazole is inexpensive.
What are the side effects of metronidazole?
The most common are nausea, a sharp metallic taste, headache, loss of appetite, diarrhea or stomach cramps, and a vaginal yeast infection. With the vaginal gel, the label reports vaginal discharge in 12% of women and yeast infection in 10%. Rare but serious effects include numbness or tingling in the hands or feet, seizures, confusion or trouble walking steadily, and severe skin reactions. Stop and call your prescriber if any nerve symptoms appear.
How long do metronidazole side effects last?
Most stop within a day or two of your last dose. Metronidazole's half-life is about 8 hours, so the drug is largely gone about 2 days after you stop, which is why the label's alcohol and breastfeeding cautions run 48 to 72 hours past the last dose. Nerve-related effects, which are rare, are usually reversible but can take days to weeks to fade.
Does metronidazole cause yeast infections?
It can. Clearing the bacteria behind BV lets Candida yeast overgrow, and the labels list vaginal yeast as a side effect: 10% of women in the vaginal-gel trials. A thick, white, clumpy discharge with itching during or after treatment is a common sign. It's treatable, often with an OTC antifungal, but check with your pharmacist or prescriber first so you treat the right thing.
Can I drink alcohol while taking metronidazole?
The FDA label says no: avoid alcohol, and products containing propylene glycol, during treatment and for at least 3 days after the last dose, because of reported flushing, nausea, vomiting, cramps and headache. The CDC's 2021 STI guidelines reviewed the evidence and found no convincing proof of a true disulfiram-like reaction, calling abstinence unnecessary. Ask your prescriber which advice to follow. Many still recommend skipping alcohol for the short course.
I accidentally drank alcohol on metronidazole. What should I do?
Don't panic, and don't skip your next dose. Stop drinking for the rest of the course and the 3 days after. If you feel fine, nothing else is needed. If you get flushing, nausea, vomiting, a headache or cramps, rest and sip water; these usually pass in a few hours. Get urgent care for fainting, chest pain, a racing heartbeat or vomiting you can't stop. Call us anytime during business hours to talk it through with a pharmacist.
Why is metronidazole vaginal gel used at bedtime?
The label says once-daily gel should be applied at bedtime. Lying down keeps the gel in place for hours instead of leaking out, so more of the dose stays where the infection is. The usual course is one full applicator (5 g) each night for 5 days. A panty liner helps with the discharge, which is common.
How long does it take metronidazole to work?
Tablets reach peak blood levels in about 1.5 hours, and many people with BV or trichomoniasis feel better within a few days. Keep taking it for the full prescribed course even after symptoms fade, since stopping early is a common reason infections come back. For trichomoniasis, sexual partners need treatment too, or you can be reinfected.
Is metronidazole safe during pregnancy or breastfeeding?
The label contraindicates it for trichomoniasis in the first trimester. Later in pregnancy, published studies of more than 5,000 exposed pregnancies mostly found no increase in birth defects, and CDC guidelines use it to treat BV and trichomoniasis in pregnancy. For breastfeeding, metronidazole passes into milk; the label offers the option to pump and discard during treatment and for 48 hours after the last dose. Decide with your OB.
Can metronidazole treat a UTI or yeast infection?
No. Metronidazole targets anaerobic bacteria and protozoa such as Trichomonas. It doesn't treat typical UTIs (usually E. coli) or yeast infections (Candida, a fungus), and it can actually trigger a yeast infection. Taking the wrong medicine for the organism delays the right treatment.
Is metronidazole the same as Flagyl?
Yes. Flagyl is the original brand name for oral metronidazole. Nearly all prescriptions today are filled with generic metronidazole tablets, which are the same medicine at a fraction of the brand price.
Sources
- FLAGYL (metronidazole) — FDA-approved prescribing information, including boxed warning — U.S. National Library of Medicine (DailyMed) / Pfizer
- Metronidazole tablets — FDA-approved prescribing information (trichomoniasis, amebiasis, anaerobic infection dosing) — U.S. National Library of Medicine (DailyMed)
- Metronidazole vaginal gel 0.75% — FDA-approved prescribing information (dosing, adverse reactions) — U.S. National Library of Medicine (DailyMed)
- Bacterial Vaginosis — STI Treatment Guidelines, 2021 — U.S. Centers for Disease Control and Prevention
- Trichomoniasis — STI Treatment Guidelines, 2021 — U.S. Centers for Disease Control and Prevention
- Patient Care for Giardia Infection — U.S. Centers for Disease Control and Prevention
- Clinical Practice Guideline: 2021 Focused Update on Management of Clostridioides difficile Infection in Adults — Infectious Diseases Society of America / SHEA
- Can Metronidazole Cause a Disulfiram-Like Reaction? A Case-Control Study — PubMed / Wisconsin Medical Journal
- NADAC (National Average Drug Acquisition Cost) — metronidazole 250 mg and 500 mg tablets — CMS
- Metronidazole / Flagyl price data (average retail cash price) — GoodRx (consumer price reference)