Evaluating the minimum active concentrations of penicillin G and V and of retard forms in clinical conditions.

: Following several signals indicating the inefficiency of the clinical treatment with various penicillin preparations in some cases, we decided to study the seric penicillin concentrations in the patients hospitalized in the "V. Babes" Hospital of Infectious Diseases, after administration of the various Romanian made forms of penicillin currently used in the therapy of streptococcal infections and in the prophylaxis of the sequelae of these infections. The data obtained on groups exceeding 30 persons by using two methods of determining the penicillin concentrations the dilutions and the diffusimetric methods revealed protective penicillin seric levels satisfactory for penicillin G and Efitard, according to the present treatment schemes. After 5 days from Moldamin administration only 45.4% of children and 43.3% of adults were found to have satisfactory penicillin concentrations. The administration of penicillin V reaches active penicillin concentrations in terms of the dose administered. The paper points out only one of the causes which together with others (such as beta-lactamase production and tolerance), contribute to the unsuccessful treatment with various forms of penicillin.