penicillin V

Medically Reviewed on 5/16/2023

Brand Name: Penicillin V

Generic Name: phenoxymethyl penicillin

Drug Class: Penicillins, Natural

What is penicillin V, and what is it used for?

  • Penicillin V is effective for treatment of laryngitis, bronchitis, pneumonia, and soft tissue and skin infections caused by susceptible bacteria.
  • It also is used for preventing recurrence of rheumatic fever and chorea (a disorder of uncontrolled movement of the body).
  • Only mild to moderate infections are treated with oral penicillin V.
  • Patients with more severe infections are given penicillin by injection.

What are the side effects of penicillin V?

Common side effects of penicillin V include:

Patients with a history of allergic reactions to other penicillins should not receive penicillin V. Persons who are allergic to the cephalosporin class of antibiotics, which are related to the penicillins, for example, cefaclor (Ceclor), cephalexin (Keflex), and cefprozil (Cefzil), may or may not be allergic to penicillins.

Serious but rare reactions include:

  • seizures,
  • hemolytic anemia,
  • super infection,
  • reduced kidney function,
  • severe allergic reactions (anaphylaxis), and
  • low platelet or red blood cell count.

Penicillins can alter the normal bacteria in the colon and encourage overgrowth of some bacteria such as Clostridium difficile which causes inflammation of the colon (pseudomembranous colitis). Patients who develop signs of pseudomembranous colitis after starting penicillin (diarrhea, fever, abdominal pain, and possibly shock) should contact their doctor immediately.


Bowel regularity means a bowel movement every day. See Answer

What is the dosage for penicillin V?

The usual adult dose of penicillin V is 125 to 500 mg every 6-8 hours.

Which drugs interact with penicillin V?


  • Probenecid (Benemid) causes an increase in the level of penicillin in the blood by reducing the elimination of penicillin by the kidneys. In fact, sometimes probenecid is combined with penicillin so that a smaller amount of penicillin results in higher blood levels.
  • Penicillin may reduce the effectiveness of BCG live vaccine (used for prevention of tuberculosis) or live typhoid vaccine. Penicillin therapy should be completed before giving live bacterial vaccines.

Pregnancy and breastfeeding


  • Penicillin is considered safe during pregnancy.
  • Penicillin is excreted in breast milk and may cause diarrhea or allergic responses in nursing infants. If penicillin is used while nursing, the potential benefit of penicillin for the mother should be weighed against the potential risk of side effects in the infant. Penicillin is used for treating infections in infants.

What else should I know about penicillin V?

What preparations of penicillin V (phenoxymethyl penicillin) are available?

Tablets: 250 and 500 mg. Powder: 125 and 250 mg/5 mL.

How should I keep penicillin V (phenoxymethyl penicillin) stored?

  • Tablets should be stored between 15 C and 30 C (59 and 86 F).
  • After mixing with water, the solution should be kept refrigerated and can be used for up to 14 days after it is reconstituted by the pharmacist.
  • It must be shaken before each use and should be kept well-sealed.


Penicillin V (Veetids and Pen-Vee-K have been discontinued) is an antibiotic prescribed to treat infections from a variety of bacteria that causes infections of the middle ear, tonsils, throat, bronchitis, pneumonia, urinary tract, and gonorrhea. Side effects include rash, itching, abdominal pain, vomiting, nausea, diarrhea. Drug interactions, dosage, and pregnancy and breastfeeding safety should be reviewed prior to taking any medication.

Treatment & Diagnosis

Medications & Supplements

Prevention & Wellness

Health Solutions From Our Sponsors

FDA Logo

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Medically Reviewed on 5/16/2023
FDA Prescribing Information