Penicillin VK

  • Generic name: Penicillin v potassium (Phenoxymethylpenicillin), phenoxymethyl analog of penicillin G
  • Brand names: Beepen VK, Ledercillin VK, Pen-Vee K, Pen-VK, V-Cillin K, Veetids
  • Class: Natural penicillin antibiotic

What is Penicillin used for?

  • Strep throat (group A beta-hemolytic streptococcal pharyngitis), mild respiratory tract infections, middle ear infection
  • Scarlet fever, prevention of rheumatic fever
  • Infections of the oropharynx: abscessed tooth, Vincent’s gingivitis (inflammation of gum)

Penicillin is safe, inexpensive, and continues to be widely prescribed today. However, it should not be used as initial treatment of severe infections.

Strict contraindications

  • Known allergy to penicillins. If you feel signs of an allergic reaction, such as skin rash, itching, shortness of breath, chills, seek medical attention immediately.

Penicillin alternatives

Acceptable alternatives to penicillin in patients with penicillin allergy:

  • Type I hypersensitivity reaction (occurs promptly within hours and manifests with urticaria, anaphylaxis, pruritus, laryngeal edema): macrolides, clindamycin, and sulfonamides 3 are safe for those allergic to penicillin.
  • Non-type I hypersensitivity reaction (delayed, often manifests after 3 days with maculopapular rash): 2nd or later generation cephalosporins2, e.g. cefprozil, ceftriaxone, cefuroxime (Ceftin), cefdinir (Omnicef).
    Warning! First-generation cephalosporins, e.g. cephalexin (Keflex), cefadroxil, and cefazolin, confer a higher risk of cross-allergy.

Can you take Penicillin and drink alcohol?

There is no interaction between alcohol and penicillin1. If you drink in moderation, alcohol is unlikely to harm.

Penicillin VK dosage

Pharyngitis and tonsillitis caused by group A β-hemolytic streptococci (strep throat), upper respiratory tract infections, scarlet fever: 125 to 250 mg every 6-8 hours for 10 days; or, alternatively, 500 mg every 12 hours for 10 days.

Tooth abscess: The usual dosage for periodontal or tooth abscess is 500 mg every 6 hours for seven days.

Urinary tract infections: Uncomplicated UTI may be treated with the dosage 500 mg given 4 times daily4. However, penicillin is not recommended as a first choice for UTI.


  • 1. Penicillin V Monograph Reference guide from the American Society of Health-System Pharmacists.
  • 2. Campagna JD, Bond MC, Schabelman E, Hayes BD. The use of cephalosporins in penicillin-allergic patients. J Emerg Med. 2012 May;42(5):612-20
  • 3. Gerber MA, Baltimore RS, Eaton CB, Gewitz M, Rowley AH, Shulman ST, Taubert KA. Prevention of rheumatic fever and diagnosis and treatment of acute Streptococcal pharyngitis. Circulation. 2009 Mar 24;119(11):1541-51. PubMed
  • 4. Gower PE, Marshall MJ, Dash CH. Clinical, pharmacokinetic and laboratory study of penicillin V in the treatment of acute urinary infection. J Antimicrob Chemother. 1975 Jun;1(2):187-92.

Last updated: February, 2015

Quick facts

  • The molecule of penicillin V (phenoxymethylpenicillin) has electronegative oxygen on the acyl side chain.
  • As a result, it has better acid stability than penicillin G and stable enough to survive in the stomach acid.
  • It is relatively non-toxic, safe in pregnancy, and reasonably priced in comparison with other antibiotics.