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Penicillin VK


What is penicillin VK?

Penicillin VK (also called Pen-Vee K®, V-Cillin K®, or Veetids®) is used to prevent or treat infections. It is available in 250-mg and 500-mg tablets and a liquid suspension. All are taken by mouth.

How to give and store penicillin VK

  • Take penicillin VK on an empty stomach if possible.
  • Shake the oral liquid well before you take it. Use an oral syringe or medicine cup to be sure you are taking the correct amount.
  • Store the liquid in the refrigerator. Discard it after 14 days or when the date on the label expires.

Possible side effects of penicillin VK

  • Nausea, vomiting
  • Diarrhea
  • Rash
  • Black “hairy” tongue
  • Loss of appetite
  • Stomach pain
  • Allergic reaction with these symptoms: rash, hives, itching, chills, fever, short of breath, muscle aches, swelling of face or neck, headache, tight feeling in throat, and cough

These are the most common side effects, but there may be others. Please report all side effects to the doctor or nurse.

In case of a severe side effect or reaction, call the doctor, nurse, or pharmacist at 595-3300. If you are outside the Memphis area, dial toll-free 1-866-2STJUDE (1-866-278-5833), and press 0 once the call is connected.

Special instructions for penicillin VK

  • Tell your doctor before taking penicillin VK if you have had an allergic reaction to any other penicillin. If you have any allergic symptoms (listed on page 1) or you have severe or watery diarrhea, tell your doctor right away.
  • If penicillin causes stomach upset on an empty stomach, you may take it with food.
  • Finish all doses of this medicine as instructed by your doctor, even if you think your condition is better. Do not stop taking this medicine unless your doctor tells you to do so.
  • Do not take probenecid or methotrexate while you are taking penicillin VK without telling your doctor. Probenecid may increase the level of penicillin VK in your body. Penicillin VK may increase the level of methotrexate in your body.
  • While taking penicillin, birth control medicines that contain estrogen might not be effective. Use a second birth control method for at least one (1) month after taking penicillin VK.
  • Penicillin VK may cause a false-positive urine test result when checking your urine for sugar (glucose) levels.


This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.

St. Jude complies with health care-related federal civil rights laws and does not discriminate on the basis of race, color, national origin, age, disability, or sex.

ATTENTION: If you speak another language, assistance services, free of charge, are available to you. Call 1-866-278-5833 (TTY: 1-901-595-1040).

ATENCIÓN: si habla español, tiene a su disposición servicios gratuitos de asistencia lingüística. Llame al 1-866-278-5833 (TTY: 1-901-595-1040).

تنبيه: إذا كنت تتحدث باللغة العربية فيمكنك الاستعانة بخدمات المساعدة اللغوية المتوفرة لك مجانا. .يرجى الاتصال بالرقم. 5833-278-866-1  (الهاتف النصي: 1040-595-901-1).