penicillin V potassium

  • Medical Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: Charles Patrick Davis, MD, PhD
    Charles Patrick Davis, MD, PhD

    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

What is penicillin v potassium-oral solids, and how does it work (mechanism of action)?

Penicillin V potassium is penicillin antibiotic that is administered orally. Penicillin V potassium kills bacteria by inhibiting bacterial cell wall synthesis. Some bacterial species against which penicillin V potassium has shown high in-vitro activity include some species of staphylococci, streptococci (groups A, C, G, H, L, and M), and pneumococci. Other bacterial species against which this medication has activity includes Corynebacterium diphtheria, Bacillus anthracis, Clostridia, Actinomyces bovis, Streptobacillus moniliformis, Listeria monocytogenes, Leptospira, Neisseria gonorrhea, and Treponema pallidum.

Penicillin V potassium offers some distinct advantages over penicillin G. Penicillin V potassium is much more resistant to inactivation by stomach acidity, and therefore results in better drug absorption and higher levels in the blood. On average, blood levels of penicillin V potassium is two to five times higher than that observed with same dose of oral penicillin G.

Penicillin V potassium was approved by the US Food and Drug Administration (FDA) in 1956.

What brand names are available for penicillin v potassium-oral solids?

Beepen-VK, Penicillin VK, V-Cillin-K

Is penicillin v potassium-oral solids available as a generic drug?


Do I need a prescription for penicillin v potassium-oral solids?


What are the side effects of penicillin v potassium-oral solids?

The most common side effects to oral penicillin are:

Rare (occurring at frequency of <1%) but serious side effects include:

  • acute kidney damage,
  • seizures,
  • severe skin rashes, and
  • hemolytic anemia.

Hypersensitivity reactions have been reported with penicillin use.

What is the dosage for penicillin v potassium-oral solids?

The usual recommended dosage for adults and children 12 years and older are as follows:

Which drugs or supplements interact with penicillin v potassium-oral solids?

Penicillin V potassium may inhibit the renal tubular secretion (elimination of the drug via the kidneys) of methotrexate (Trexall, Rheumatrex). Co-administration may result in higher blood levels of methotrexate and increases the risk of methotrexate toxicity (side effects).

Penicillin V potassium may interfere with the effectiveness of the live typhoid vaccine. Administration of the vaccine must be separated by at least 24 hours from the last dose of the antibiotic.

Antibiotics such as penicillin V potassium may decrease the effectiveness of certain oral contraceptives or birth control pills. Patients may use an alternative form of birth control (for example, condoms) while on antibiotic therapy to prevent unexpected pregnancies.

Penicillin antibiotics may inhibit vitamin K synthesis due to their effect on the normal intestinal flora. Therefore, co-administration of warfarin (a vitamin K antagonist) with penicillin V potassium may increase the risk of bleeding.

Is penicillin v potassium-oral solids safe to take if I'm pregnant or breastfeeding?

Penicillin V potassium is classified as FDA pregnancy risk category B (Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women). Use of penicillin products in humans has not shown any evidence of fetal harm. Additionally, no evidence of fetal harm has been reported in animal studies. However, there is a lack of adequate and well controlled studies in pregnant women. As with all medications, use of penicillin V potassium during pregnancy requires careful evaluation of treatment benefits and potential risk to the fetus.

Penicillin V potassium is excreted in breast milk. Penicillin products have been reported to cause diarrhea, candidiasis (fungal infections), and skin rash in breast feed babies. Due to the lack of safety data, this medication should be used cautiously in females who are breastfeeding. Penicillin type antibiotics are used for treating infection in children.

What else should I know about penicillin v potassium-oral solids?

What preparations of penicillin v potassium-oral solids are available?

Powder for oral solution: 125 mg/5 ml (100 ml, 200 ml); 250 mg/5 ml (100 ml, 200 ml); Tablets: 250 mg, 500 mg

How should I keep penicillin v potassium-oral solids stored?

Reconstituted product may be stored for up to 14 days and requires refrigeration 2.2 C to 7.7 C (36 F to 46 F). Un-reconstituted product and oral tablets may be stored at room temperature between 20 C to 25 C (68 F to 77 F).


Penicillin V potassium (Beepen-VK, Penicillin VK, V-Cillin-K) is an antibiotic prescribed to treat a variety of infections such as the respiratory tract, middle ear, skin, sinuses, and soft tissues. Penicillin V potassium also is prescribed to prevent rheumatic fever. Side effects, drug interactions, patient safety, storage, and dosage information should be reviewed prior to taking this medication.

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REFERENCE: FDA Prescribing Information.