Evaluation of secondary prophylactic schemes, based on benzathine penicillin G, for rheumatic fever in children.

Serum concentrations of penicillin were measured in children with rheumatic fever. The adequacy of the values after administration of 1.2 million units of benzathine penicillin G every 2 or 3 weeks was confirmed; the adequacy of a 4-week regimen was questionable. The administration of 0.6 million units every 3 weeks was found to be inadequate to maintain serum levels high enough for the secondary prophylaxis of rheumatic fever.