Penicillin V (Penicillin V Potassium) - Description and Clinical Pharmacology

To reduce the development of drug-resistant bacteria and maintain the effectiveness of Penicillin V Potassium for Oral Solution and other antibacterial drugs, Penicillin V Potassium for Oral Solution should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.

DESCRIPTION

Penicillin V Potassium for Oral Solution, the potassium salt of penicillin V, monopotassium [2S-(2α,5α,6β)]-3,3-dimethyl-7-oxo-6-[(phenoxyacetyl)amino]-4-thia-1-azabicyclo [3.2.0] heptane-2-carboxylate, is an antibacterial agent having the following structural formula:

C₁₆H₁₇KN₂O₅S MW = 388.48.

Penicillin V Potassium for Oral Solution is a powder which, when reconstituted as directed, yields a solution in which each 5 mL contains penicillin V potassium equivalent to 125 mg (200,000 units) or 250 mg (400,000 units) penicillin V. The inactive ingredients are acacia, citric acid, DL-menthol, FD&C Red No. 40, natural and artificial flavorings, sodium benzoate, sodium citrate, sodium saccharin, sucrose, and thymol.

CLINICAL PHARMACOLOGY

Penicillin V exerts a bactericidal action against penicillin-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. The drug 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.

The potassium salt of penicillin V has the distinct advantage over penicillin G in resistance to inactivation by gastric acid. It may be given with meals; however, blood levels are slightly higher when the drug is given on an empty stomach. Average blood levels are two to five times higher than the levels following the same dose of oral penicillin G and also show much less individual variation.

Once absorbed, penicillin V is about 80% bound to serum protein. Tissue levels are highest in the kidneys, with lesser amounts in the liver, skin, and intestines. Small amounts are found in all other body tissues and the cerebrospinal fluid. The drug is excreted as rapidly as it is absorbed in individuals with normal kidney function; however, recovery of the drug from the urine indicates that only about 25% of the dose given is absorbed. In neonates, young infants, and individuals with impaired kidney function, excretion is considerably delayed.