RHEUMATIC-FEVER PROPHYLAXIS IN SOUTH-AFRICA - IS BICILLIN 1,2-MILLIONUNITS EVERY 4 WEEKS APPROPUIATE

Rheumatic fever is a major health problem in South Africa. Although in tramuscular benzathine penicillin (bicillin) 1,2 million units (MU) ev ery 4 weeks is widely used for secondary prophylaxis, studies in other countries have shown a recurrence rate of 3 - 8% over 5 - 6 years in patients on this regimen. It has been recommended that serum penicilli n concentrations should be maintained above 0,02 mg/ml to prevent such recurrences. The World Health Organisation (WHO) and the American Hea rt Association have recommended since 1988 that patients in high-risk areas for the development of rheumatic fever should receive benzathine penicillin 1,2 MU every 3 weeks rather than every 4. The aims of this study were, firstly, to determine the prevalence of serum penicillin concentrations below 0,02 mu g/ml in rheumatic fever patients on benza thine penicillin 1,2 MU 1-weekly and, secondly, to study the effect of increasing the dose to 1,8 MU 4-weekly in patients with subtherapeuti c concentrations. Forty-five of 51 rheumatic fever patients (88%) in t his study on benzathine penicillin 1,2 MU 4-weekly had low serum penic illin concentrations (< 0,02 mu g/ml) at the end of the 4th week after the injection. Penicillin was detected in the urine of 30 of the 45 p atients (67%) with low concentrations, suggesting that such patients h ave tissue-bound penicillin which might be important in preventing rhe umatic fever. The 15 patients (33%) with subtherapeutic serum penicill in concentrations and no detectable penicillin in the urine could be a t very high risk for recurrent attacks of rheumatic fever. Fourteen of 29 patients (48%) given the higher dose of benzathine penicillin (1,8 MU 4-weekly) had subtherapeutic serum penicillin concentrations at th e end of the 4th week after the injection, but in all 29 penicillin wa s detected in the urine. Review of our present policy of secondary pro phylaxis for rheumatic fever is necessary. Concentrated preparations o f benzathine penicillin (600 000 U/ml) are not available in South Afri ca; administration of a higher dose (1,8 MU) 4-weekly would therefore require a double injection, which could affect compliance adversely. W e recommend that rheumatic fever patients in our area should receive b enzathine penicillin 1,2 MU 3-weekly as recommended by the WHO until s trategies for secondary prophylaxis have been evaluated further.