Firvanq comes as a powder for oral solution, which means it needs to be mixed with water before using.

Steps to Take Firvanq:

1. The pharmacist will mix the powder with water to make a liquid.

    

2. Shake the bottle well before each dose.

    

3. Measure your dose using the special measuring tool (not a spoon).

    

4. Take it by mouth, usually 4 times a day (every 6 hours).

    

5. Take it at the same time every day for the full treatment course—even if you feel better before it ends.

    

Do not stop early, as this can cause the infection to come back.

Firvanq contains vancomycin, which is a strong antibiotic. It works by killing the bacteria or stopping them from growing. This helps the body fight the infection and return to normal.

When you take Firvanq by mouth, it stays mostly in the intestines, where the infection is. It does not get absorbed much into the blood, which is good, because the medicine can work right where the infection is—inside the colon.

This makes Firvanq very effective against C. diff, which causes severe stomach issues after taking other antibiotics.

Like all medicines, Firvanq can cause side effects. Most people have mild or no side effects, but some may experience more serious problems.

Common Side Effects:

• Nausea

   

• Stomach pain or cramping

   

• Bloating

   

• Diarrhea (may be hard to tell if it’s a side effect or the infection itself)

   

• Headache

   

• Bad taste in the mouth

   

Serious Side Effects (rare):

• Allergic reaction (rash, itching, swelling, trouble breathing)

   

• Hearing problems (ringing in ears, hearing loss—rare when taken by mouth)

   

• Kidney issues (rare with oral form)

   

• Red man syndrome (more common with IV form, not oral)

   

If you notice bloody diarrhea, fever, or worsening symptoms, call your doctor immediately.

Before using Firvanq, tell your doctor if you:

• Have kidney problems

   

• Have hearing loss or ear problems

   

• Are pregnant or breastfeeding

   

• Are allergic to vancomycin or any antibiotics

   

Important Precautions:

• Finish the full course, even if you feel better

   

• Do not share your medication with anyone else

   

• Firvanq is only for gut infections—not for colds, flu, or other body infections

   

• If symptoms return after stopping the medicine, contact your doctor right away

   

Taking antibiotics when you don’t need them can lead to antibiotic resistance, which makes infections harder to treat in the future.

Firvanq is not absorbed much into the body, so it has fewer interactions than other drugs. But you should still tell your doctor if you take:

• Other antibiotics

   

• Water pills (diuretics)

   

• Kidney medicines

   

• Cholestyramine (used for high cholesterol)

   

Always tell your doctor and pharmacist about all other medicines, including herbal and over-the-counter drugs.

Adults:

• 125 mg (5 mL) by mouth, 4 times daily

   

• Duration: 10 days

   

Children:

• Dose is based on weight and age

   

• Pediatric dosing must be decided by a pediatrician

   

Missed Dose:

• If you miss a dose, take it as soon as you remember.

   

• If it’s close to your next dose, skip the missed one—do not double up.

   

Storage:

• Store the liquid in the refrigerator

   

• Shake well before use

   

• Discard after 14 days

   

Check the label or ask your pharmacist if you’re unsure how to store or take the medicine properly.

Firvanq is a prescription-only medication, which means:

• You need a doctor’s diagnosis to use it

   

• It is not available over-the-counter

   

• A licensed pharmacist must prepare the solution

   

• You must follow the full treatment course to prevent reinfection

   

Doctors often prescribe Firvanq based on a positive C. diff test, especially if symptoms are severe or other antibiotics haven’t worked.

You may also need follow-up tests to make sure the infection is gone.

• What is Firvanq used for?
  It is used to treat Clostridioides difficile (C. difficile)–associated diarrhea and enterocolitis caused by Staphylococcus aureus (including MRSA) that affects the intestines.

• What is the brand name?
  Firvanq® (U.S.).

• What is the active ingredient?
  Vancomycin hydrochloride.

• How does Firvanq work?

  • Vancomycin is an antibiotic that inhibits bacterial cell wall synthesis, leading to bacterial death.

  • It works locally in the gut, not systemically absorbed, which makes it effective against intestinal infections like C. difficile.

• What type of medication is it?
  A glycopeptide antibiotic (oral formulation).

• How is Firvanq taken?

  • By mouth as an oral solution (liquid).

  • Take exactly as prescribed, usually four times daily for 10 days for C. difficile.

  • Shake the bottle well before use and measure with the provided dosing syringe or cup.

• What are the available strengths and forms?

  • 25 mg/mL and 50 mg/mL oral solutions (after reconstitution).

  • Supplied as a powder for oral solution in single-use bottles.

• How long does it take to work?

  • Symptoms like diarrhea and fever often begin to improve within 2–3 days, but the full course must be completed to prevent relapse.

• What are the common side effects?

  • Nausea

  • Stomach pain

  • Diarrhea (may persist during treatment)

  • Bloating or gas

  • Mild rash or itching

• Are there serious side effects?
  Rare but possible:

  • Allergic reaction (rash, hives, swelling, breathing difficulty)

  • Hearing loss (with prolonged use or high doses)

  • Severe diarrhea or colitis recurrence

  • Low white blood cell count (neutropenia)

• Who should not take Firvanq?

  • Those with a known allergy to vancomycin or similar antibiotics.

  • Use cautiously in patients with kidney disease (if receiving IV vancomycin simultaneously).

• Can Firvanq cause antibiotic-associated diarrhea?
  Yes — though used to treat C. difficile, other bacteria may sometimes overgrow, causing mild diarrhea.

• Can it be used in children?
  Yes — approved for pediatric use, with dosing based on body weight.

• Can it be used during pregnancy?
  Yes, if clearly needed. It is minimally absorbed when taken orally, making systemic exposure low.

• Can it be used while breastfeeding?
  Generally considered safe, since very little passes into the bloodstream or breast milk.

• Does Firvanq interact with other medications?

  • Oral Firvanq has few systemic interactions.

  • Use caution if also receiving IV vancomycin (may increase total exposure).

  • Always inform your doctor about all current antibiotics or nephrotoxic drugs.

• How should I store Firvanq?

  • Before mixing: Store the dry powder at room temperature (20°C–25°C / 68°F–77°F).

  • After reconstitution: Refrigerate (2°C–8°C / 36°F–46°F) and use within 14 days.

  • Do not freeze. Shake well before each dose.

• Is there a generic available?
  No — Firvanq® is the brand formulation of oral vancomycin; however, vancomycin oral capsules and compounded liquids are available generically.

• Where can I get it?
  Available by prescription only, dispensed at most retail or hospital pharmacies.