Plasma Penicillin Levels from Oral Penicillins V and G and Intramuscular Penicillin G.

Abstract

Oral penicillin V gave higher and better sustained levels of penicillin activity in the plasma than oral buffered potassium penicillin G at each of 3 dosage levels, viz., 200,000 U, 400,000 U and 1 million U. Intramuscular penicillin G yielded higher and better sustained levels than oral penicillin V in equivalent doses given at levels of 400,000 or 1 million U. An intramuscular dose of 200,000 U of penicillin G produced higher peak levels and these occurred earlier but were less well sustained than with this amount of oral penicillin V; the total amount of penicillin absorbed from this amount of penicillin was not significantly different for these 2 dosage forms. Persons over 60 years of age attained peak levels later; in general they had higher and better sustained levels of penicillin in the plasma from any given dose than did younger individuals.