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Metronidazole

Common Brand Names: Flagyl, MetroGel, MetroCream

Drug Information

Medically reviewed by Jessica Swirble, PharmD
Last updated on March 26, 2025

Drug Information | Side Effects | Use & Dosage | Request an Online Prescription

Quick facts

  • Brand Name: Flagyl, MetroGel, MetroCream
  • Generic Name: Metronidazole
  • Uses: Treatment of bacterial and parasitic infections
  • Drug Class: Nitroimidazole antibiotic
  • Availability: Prescription only
  • Generic Status: Yes
  • Controlled Substance: No

What is metronidazole?

Metronidazole is an antibiotic medication commonly used to treat bacterial and parasitic infections. It belongs to a class of antibiotics known as nitroimidazoles.

What conditions does metronidazole treat?

Metronidazole is prescribed to treat various infections caused by bacteria and parasites, including:

  • Bacterial vaginosis (BV)
  • Trichomoniasis (a sexually transmitted infection)
  • Amoebiasis (intestinal infection)
  • Giardiasis (intestinal infection)
  • Helicobacter pylori infection (associated with peptic ulcers and gastritis)
  • Clostridium difficile infection (a bacterial infection causing diarrhea and colitis)
  • Dental infections
  • Skin and soft tissue infections

Metronidazole is not effective against viral infections like the common cold or flu.

How does metronidazole work?

Metronidazole works by disrupting the DNA and cellular structure of bacteria and parasites, leading to their death.

It's important to note that metronidazole should not be used for viral or fungal infections.

How do I take metronidazole?

Metronidazole is available in various forms, including oral tablets, capsules, extended-release tablets, and topical formulations (creams, gels). The dosage and duration of treatment will depend on the type and severity of the infection, as well as your medical condition and response to the medication.

Complete the full course of metronidazole as prescribed, even if your symptoms improve before the treatment is finished. Stopping the medication early can cause the infection to reoccur.

Consult your healthcare provider for specific instructions on how to take metronidazole properly.

How long until I feel better?

The time it takes to experience symptom relief while taking metronidazole can vary depending on the type and location of the infection, its severity, and your overall health. Some individuals may notice improvement within a few days, while others may require a longer duration of treatment.

Continue taking metronidazole as directed by your healthcare provider and complete the full prescribed course to ensure effective treatment.

Are there other uses for metronidazole?

In addition to its primary uses in treating bacterial and parasitic infections, metronidazole may have off-label uses or be part of combination therapies for certain conditions. Off-label uses may include:

  • Management of rosacea (a skin condition characterized by facial redness and acne-like eruptions)
  • Treatment of refractory or recurrent Clostridium difficile infections
  • Combination therapy for certain dental infections

Discuss any alternative uses of metronidazole with your healthcare provider.

Dosage forms of metronidazole

Metronidazole is available in various dosage forms, including:

  • Oral tablets: Available in strengths ranging from 250mg to 500mg.
  • Oral capsules: Available in strengths ranging from 375mg to 500mg.
  • Extended-release tablets: Available in strengths ranging from 750mg to 1000mg.
  • Topical creams/gels: Available in various concentrations for skin and vaginal use.

Generic versions of metronidazole are available under various brand names.

Metronidazole is a prescription medication. You will need a valid prescription from a licensed healthcare provider to obtain this drug.

Side Effects and Precautions for Metronidazole


Drug Information | Side Effects | Use & Dosage | Request an Online Prescription

What are the side effects of metronidazole?

The use of metronidazole has been shown to cause side effects in some patients.

Common mild side effects of metronidazole use include:

  • Nausea
  • Vomiting
  • Diarrhea
  • Abdominal pain or cramping
  • Upset stomach
  • Headache
  • Metallic taste in the mouth
  • Dry mouth
  • Dizziness or lightheadedness
  • Tongue irritation
  • Yeast infection
  • Vaginal discharge and irritation (vaginal gel)

More severe side effects include:

  • Allergic reactions (rash, itching, swelling of the face, lips, or tongue, difficulty breathing)
  • Severe skin reactions (blistering, peeling, redness)
  • Neurological symptoms (numbness, tingling, burning sensations, coordination problems)
  • Seizures or convulsions
  • Blood disorders (decreased white blood cell count, decreased platelets)
  • Liver dysfunction (jaundice, dark urine, abdominal pain)

Seek medical attention immediately if you experience any severe symptoms while taking metronidazole. If you experience mild side effects that become severe or do not go away after a few days, speak to a healthcare provider right away.

What should I tell my healthcare provider before using metronidazole?

Tell your healthcare provider about any existing medical conditions, allergies, or other medications you are taking before starting treatment with metronidazole. This includes prescription drugs, over-the-counter medications, and dietary supplements, as they may interact with this drug.

Tell your provider if you are taking these medications or supplements:

  • Blood thinners (anticoagulants)
  • Azithromycin
  • Disulfiram (used to treat alcohol dependence)
  • Cimetidine (used to reduce stomach acid)
  • Citalopram
  • Clarithromycin
  • Haloperidol
  • Levofloxacin
  • Lithium (used to treat mood disorders)
  • Methadone
  • Phenobarbital or phenytoin (anticonvulsants)
  • Ritonavir
  • Warfarin (an anticoagulant)
  • Ziprasidone
  • Carbamazepine (used to treat seizures and nerve pain)

You should also mention medical conditions such as:

  • Allergic reactions to medications
  • Liver disease
  • Blood disorders
  • Neurological disorders or seizures
  • Kidney disease

If you are pregnant, planning to become pregnant, or breastfeeding, consult your healthcare provider before using metronidazole to assess potential risks and benefits.

Are there any other special instructions I should follow?

Avoid consuming alcohol or products containing alcohol, as it may cause a reaction (flushing, nausea, vomiting, rapid heartbeat).

Take metronidazole with food to minimize stomach upset.

Use caution when driving or operating machinery, as metronidazole may cause dizziness or drowsiness.

Your healthcare provider will provide specific instructions regarding the use of metronidazole with food, beverages, and other medications. It's essential to follow their guidance to ensure the effectiveness of the treatment and minimize the risk of side effects.

What should I do in case of an overdose?

The symptoms of a metronidazole overdose include:

  • Nausea
  • Vomiting
  • Loss of coordination

If you experience any of these symptoms, call the poison control helpline at 1-800-222-1222. If an individual has collapsed, is having seizures, or is unresponsive, call 9-1-1 immediately.

Proper Use & Dosage Information for Metronidazole


Drug Information | Side Effects | Use & Dosage | Request an Online Prescription

What is the typical starting dose for metronidazole?

Metronidazole is available in various forms:

  • Oral tablets (250 mg, 500 mg)
  • Oral extended-release tablets (750 mg)
  • Oral capsules (375 mg)
  • Oral suspension (500 mg/5 mL)
  • Topical gel (0.75%, 1%)
  • Topical cream (0.75%, 1%)

The typical starting dose of metronidazole can vary depending on the specific infection being treated, the patient's age, weight, medical history, and other individual factors. It is crucial to follow your healthcare provider's instructions regarding dosage and administration carefully.

For the treatment of bacterial infections, the typical starting doses may be:

  • For mild to moderate infections: 500 mg taken orally every 12 hours for 7 to 10 days.
  • For severe infections or certain types of infections: 500 mg to 1000 mg taken orally every 6 to 8 hours as directed by your healthcare provider.

For certain protozoal infections, the typical starting dose may be:

  • For amebiasis (intestinal): 500 mg to 750 mg taken orally three times daily for 5 to 10 days.
  • For trichomoniasis: A single dose of 2 grams taken orally or as directed by your healthcare provider.

Your healthcare provider will assess your medical history, current medications, and the nature of your infection to determine the most appropriate starting dose and duration of treatment for you.

Metronidazole should be taken exactly as prescribed by your healthcare provider. Do not exceed the recommended dose or make changes to your medication regimen without consulting your provider.

If you have any questions about your dosage, contact your healthcare provider. If you want to talk to a provider right away, book an online doctor appointment on Sesame to discuss your concerns.

What should I do if I miss a dose?

If you miss a dose, take it as soon as you remember it. If it's almost time for another dose of metronidazole, skip the missed dose and take your next dose as scheduled. Do not take or apply a double dose of metronidazole.

What do I do if I'm feeling better?

Do not discontinue or alter your metronidazole dosage without consulting with your healthcare provider. Follow your healthcare provider's instructions regarding dosing and other recommendations for taking metronidazole.

How should I store metronidazole?

Store metronidazole as directed by your healthcare provider or pharmacist. Proper storage is essential to maintain the medication's effectiveness. Metronidazole should be stored at room temperature, away from excessive heat, light, and moisture.

Keep the medication out of the reach of children and ensure that the container is tightly closed.

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