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Penicillin V Potassium


Brand names:

Generic only

Other names:

Penicillin VK, Penicillin V potassium

Often used for:

Treating or preventing infections caused by bacteria

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What is penicillin V potassium?

Penicillin is an antibiotic medicine used to treat or prevent infections caused by certain types of bacteria. There are different forms of penicillin. 

This medicine may be given in the clinic, hospital, or at home.


May be given as a liquid by mouth


May be given as a tablet by mouth

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Possible side effects

  • Diarrhea
  • Abdominal (belly) pain
  • Nausea and vomiting
  • White spots in the mouth
  • Loss of appetite

Symptoms of an allergic reaction may include rash, hives, itching, runny nose, fever, chills, headache, muscle ache, shortness of breath, coughing, tightness in the throat, dizziness, low blood pressure, pain in the chest, side, or back, or swelling of the face or neck. 

Not all patients who take penicillin V potassium will have these side effects. Common side effects are in bold, but there may be others. Please report any symptoms or side effects to your care provider or pharmacist. Find more information on side effects.

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Tips for patients and families

Be sure to discuss all questions and instructions with your doctor or pharmacist. 

  • Tell your care provider before taking penicillin V potassium if you have had an allergic reaction to any other penicillin. 
  • Methotrexate can interact with Penicillin V potassium or change the levels of the medicine in the blood. Tell your care provider and pharmacist about all medicines, vitamins, and supplements your child takes.
  • While taking penicillin V potassium, birth control medicines that contain estrogen might not be effective. Use a second birth control method for at least 1 month after taking penicillin V potassium.
  • Penicillin V potassium may cause a false-positive urine test result when checking urine for sugar (glucose) levels.

Penicillin V potassium at home

  • Take medicine on an empty stomach, 1 hour before or 2 hours after a meal, if possible. If stomach upset occurs, take medicine with food.
  • Tablets: Store tablets at room temperature.
  • Liquid: Use the measuring device that comes with the medicine. Shake the liquid medicine well before giving the medicine. Store liquid medicine in the refrigerator.    
  • Throw away any unused medicine after 2 weeks.
  • Give a missed dose as soon as possible. If it is near the time of the next dose, skip the missed dose. Do not give 2 doses at the same time. 
  • Make sure your child finishes all doses of this medicine as instructed by your care provider, even if your symptoms are better. Do not stop taking this medicine unless your care provider tells you to do so.
  • Do not share this medicine with anyone or give it for reasons other than prescribed.