INCREASING AND PROLONGING BLOOD PENICILLIN CONCENTRATIONS FOLLOWING INTRAMUSCULAR ADMINISTRATION.

(1) Restriction of fluid intake to 1,500 cc and the salt intake to 3 gm a day doubles the penicillin blood level following interrupted intramuscular [See Figure in the PDF file] injections of penicillin. (2) The administration of benzoic acid to a patient on an unrestricted diet Ilay double the penicillin blood level during similar treatment. (3) The combination of these two procedures results in a four- to eight-fold increase in penicillin blood level with a prolonged effective blood concentration.