Staphylococcal bacteraemia and endocarditis and fusidic acid.

In 1980, we reported an association between the use of fusidic acid (particularly the intravenous formulation) and jaundice in patients who had received the drug for the treatment of Staphylococcus aureus bacteraemia during the previous 10 years. We have continued to use fusidic acid for severe staphylococcal infections, but have recommended oral administration whenever possible. In the earlier study the incidence of jaundice in patients given intravenous fusidic acid was 48%, but in the recent study of 145 patients it was 17%. Whereas 71% of patients receiving fusidic acid in the earlier series were given the intravenous drug (with or without oral) only 25% of patients were given the intravenous drug in the recent series. The incidence of jaundice in those patients treated only with the oral formulation was 13% in the earlier study and 6% in the recent study. Although jaundice was usually reversible, it is nevertheless an unwanted side effect. Resistance of S. aureus to fusidic acid remains at around 1%; it may be present on primary isolation or arise during treatment. This seems to occur particularly in patients with endocarditis or bone infection despite the use of fusidic acid in combination with another antibiotic. After some 25 years of clinical use, fusidic acid remains a most useful anti-staphylococcal antibiotic; the intravenous preparation should be avoided when possible.