Penicillin V Potassium (Veetids)

• Generic name: Penicillin V Potassium
• Brand names: Penicillin VK, Veetids, Beepen-VK, Pen-Vee K
• Dosages:
  Tablets 250 mg, 500 mg;
  Powder for oral solution 125 mg/5 mL, 250 mg/5 mL
• FDA approval: July 31, 1968
• Pharmacologic category: β-lactam; Natural penicillin antibiotic
• Pregnancy risk factor: B

Penicillin is one of the most important drugs ever discovered. It was discovered in 1928 by Alexander Fleming, Professor of Bacteriology at St. Mary's Hospital in London. Penicillin is derived from Penicillium fungi.

Penicillin V potassium (Phenoxymethylpenicillin) is the phenoxymethyl analog of penicillin G. It combines acid stability with immediate solubility and rapid absorption.

Penicillin V is used to treat:

• Upper and lower respiratory tract infections (tonsillitis, pharyngitis)
• Middle ear infections
• Scarlet fever
• Skin infections
• Prophylaxis of rheumatic fever
• Ulcerative gingivitis
• Rat-bite fever (Sodoku)

Only mild to moderate infections are treated with oral formulation.

Side effects
The most common side effects are nausea, vomiting, epigastric distress, diarrhea, and black hairy tongue.

• Elimination half-life: 0.5 to 1 hr.
• Metabolism: Hepatic biotransformation is 55%.
• Excretion: Mainly renal (20% to 40% as unchanged).

A penicillin allergy is an allergic reaction that occurs when your body's immune system overreacts to penicillin antibiotics. Penicillin allergies are the most common drug allergy. The hypersensitivity reactions reported are skin eruptions (maculopapular to exfoliative dermatitis), urticaria and other serum-sicknesslike reactions, laryngeal edema, and anaphylaxis. If an allergic reaction occurs, the medicine should be discontinued and the appropriate therapy instituted.

It isn't clear why some people develop penicillin allergies while others don't. However, certain people seem to be at greater risk of developing a penicillin allergy than others are. Heredity may play a role, as well as exposure to multiple drugs over time.

According to the recent study, female sex appears to be a risk factor for penicillin allergy.2

• May be given with meals. Penicillin V potassium has the distinct advantage over penicillin G in being resistant to inactivation by gastric acid.
• Safe in pregnancy. Pregnancy risk factor B.
• Inexpensive

• Allergic reactions - the risk is approximately 1 to 2%.
• Frequent dosage regimen - short duration of action.
• Not recommended for chronic, severe or deep seated infections as therapeutic concentrations may not be achieved in the relevant tissues.

• Prophylactic treatment of sickle cell anemia in children3
• Anaerobic infections4
• Lyme disease5
• Endocarditis6

Penicillin V exerts a bactericidal action against sensitive microorganisms during the stage of active multiplication. It acts through the inhibition of biosynthesis of cell-wall mucopeptide. It is not active against the penicillinase-producing bacteria, which include many strains of staphylococci.

Penicillin exerts high in vitro activity against staphylococci (except penicillinase-producing strains), streptococci (groups A, C, G, H, L and M), and pneumococci. Other organisms sensitive in vitro to penicillin V are Corynebacterium diphtheriae, Bacillus anthracis, Clostridia, Actinomyces bovis, Streptobacillus moniliformis, Listeria monocytogenes, Leptospira, and Neisseria gonorrhoeae. Treponema pallidum is extremely sensitive.

• 1. U.S. FDA. Penicillin Prescribing Information.
• 2. Park MA, Matesic D, Markus PJ, Li JT. Female sex as a risk factor for penicillin allergy. Ann Allergy Asthma Immunol. 2007 Jul;99(1):54-8. PubMed
• 3. Fonseca PB, Braga JA, Machado AM, Brandileone MC, Farhat CK. Nasopharyngeal colonization by Streptococcus pneumoniae in children with sickle cell disease receiving prophylactic penicillin. J Pediatr (Rio J). 2005 Mar-Apr;81(2):149-54. PubMed
• 4. Edson RS, Rosenblatt JE, Lee DT. Recent experience with antimicrobial susceptibility of anaerobic bacteria: increasing resistance to penicillin. Mayo Clin Proc. 1982 Dec;57(12):737-41. PubMed
• 5. Bennet L, Danell S, Berglund J. Clinical outcome of erythema migrans after treatment with phenoxymethyl penicillin. Scand J Infect Dis. 2003;35(2):129-31.
• 6. Josefsson K, Magni L, Nord CE. High dose phenoxymethylpenicillin for preventing endocarditis. Scand J Infect Dis. 1982;14(2):131-3.