Medication

PC Pen VK

Generic name: penicillin V potassium

Pharmacist-reviewed drug information from the RxWiki encyclopedia.

Overview

PC Pen VK is a prescription medication used to treat mild to moderate infections of the ears, nose, throat, and skin. It is also used to treat scarlet fever and to prevent rheumatic fever. PC Pen VK potassium belongs to a group of drugs called antibiotics, which stop the growth of bacteria in the body.

This medication comes in tablet and oral (by mouth) solution forms and may be taken 2 to 4 times a day, with or without food.

Common side effects of PC Pen VK include nausea, vomiting, upset stomach, diarrhea, and black hairy tongue.

What is it used for?

Penicillin V potassium is a prescription medication used to treat mild to moderate infections of the ears, nose, throat, and skin. It is also used to treat scarlet fever and to prevent rheumatic fever.

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

How to take it

Take penicillin V potassium exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The penicillin V potassium dose your doctor recommends will be based on:

  • the condition being treated
  • other medical conditions you have
  • other medications you are taking
  • how you respond to this medication
  • your kidney function
  • your age

The recommended dose range for this medication is 125 mg to 500 mg given several times a day. The frequency will depend on what kind of infection is being treated.  

Warnings

Serious side effects have been reported with penicillin V potassium including:

  • hypersensitivity (severe allergic reaction). This type of reaction may be serious and possibly fatal. These reactions are more likely to occur in those with a history of penicillin hypersensitivity and/or a history of sensitivity to multiple allergens. Tell your healthcare provider right away if you start to develop signs or symptoms of a hypersensitivity reaction, which include the following:
    • chest pain
    • swelling of the face, eyes, lips, tongue, arms, or legs
    • difficulty breathing or swallowing
    • fainting
    • rash
  • diarrhea. Diarrhea is a common problem caused by antibiotics, and it usually ends when the antibacterial is discontinued. Sometimes after starting treatment with antibiotics, patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as 2 or more months after having taken their last dose of the antibacterial. If diarrhea is severe or lasts more than 2 or 3 days, contact your doctor, as this may be a sign of an infection of the bowels.
  • superinfection. Penicillin V potassium should not be used for extended periods. Prolonged use can lead to the growth of dangerous organisms that are resistant to penicillin V potassium. Take this medication for the duration prescribed by your doctor.

Do not take penicillin V potassium if you are allergic to any of its ingredients.

Side effects

Serious side effects have been reported with penicillin V potassium. See “Drug Precautions” section.

Common side effects of penicillin V potassium include:

  • nausea 
  • vomiting
  • upset stomach
  • diarrhea
  • black hairy tongue

This is not a complete list of penicillin V potassium side effects. Ask your doctor or pharmacist for more information.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Drug interactions

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

  • probenecid (Probalan, Benemid)
  • methotrexate (Rheumatrex, Trexall)
  • birth control pills

This is not a complete list of penicillin V potassium drug interactions. Ask your doctor or pharmacist for more information.

Pregnancy

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Penicillin V potassium falls into category B. There are no well-done studies that have been done in humans with penicillin V potassium. But in animal studies, pregnant animals were given this medication, and the babies did not show any medical issues related to this medication.

Breastfeeding

Tell your doctor if you are breastfeeding or plan to breastfeed.

Penicillin V potassium has been detected in human breast milk. Because of the possibility for adverse reactions in nursing infants from Penicillin VK, a choice should be made whether to stop nursing or to stop use of penicillin V potassium. The importance of the drug to the mother should be considered.

Quick facts

Continue to take this medication even if you feel well. Do not stop taking penicillin V potassium without talking to your doctor.

Store penicillin V potassium solution (after mixing with water) in the refrigerator. Discard any unused solution (not tablets) after 14 days.

Before taking penicillin V potassium, tell your doctor if you are allergic to penicillin V potassium or to any of its ingredients. Hypersensitivity (severe allergic reactions) can occur with penicillin V potassium.  These reactions are more likely to occur in those with a history of penicillin hypersensitivity.

All information on this site is provided “as-is” for informational purposes only and is not a substitute for medical advice or treatment. You should consult with a medical professional if you have any questions about your health.