A comparison of oral and intramuscular benzathine penicillin G for the prevention of streptococcal infections and recurrences of rheumatic fever.

The incidence of recurrences of rheumatic fever and streptococcal infections in 50 rheumatic subjects receiving a 200,000 unit tablet of benzathine penicillin G daily was compared with that of 56 rheumatic patients receiving 1,200,000 units of benzathine penicillin G intramuscularly every 4 weeks. Three children in the oral penicillin group, who did not take their medication regularly, developed recurrences of rheumatic fever. No recurrences occurred among the patients receiving parenteral penicillin. In patients who took the oral medication regularly, the incidence of streptococcal infections, as determined by a significant rise in antistreptolysin O titer, was the same as in those who received penicillin intramuscularly. Group A streptococci were found in the throat in about the same number of patients in each group. Only one patient receiving oral penicillin developed an allergic reaction in contrast to four in the intramuscular group. In 12 additional patients in the latter group, medication was discontinued because of repeated local reactions or because the injections upset the child emotionally. During the period of this study, in children followed in an outpatient clinic, a single daily dose of oral benzathine penicillin G, taken regularly, proved as effective in the prevention of rheumatic fever as monthly intramuscular injections of 1,200,000 units of benzathine penicillin G. The disadvantage of parenteral penicillin is the occurrence of reactions. While the use of this method is preferable for patients who cannot be relied upon to take oral medication regularly, its routine use for all patients does not appear necessary.