Abstract

Benzathine penicillin (Penidural - Wyeth) is the penicillin salt of N, N’-dibenzyl-ethylenediamine. It was originally introduced as a depot preparation for intramuscular injection, for it is only slightly soluble (1 in 6000) and low concentrations of penicillin can be detected in the blood for several weeks after a single dose. The injection has mainly been used to prevent streptococcal infection in subjects liable to rheumatic fever; 0.9 G is given every 3 to 4 weeks. It is also a simple and very effective means of eradicating streptococcal infection, which does not depend on the patient’s willingness to continue taking oral penicillin after he has begun to feel well.