Fusidic acid: new opportunities with an old antibiotic.

The extensive foreign experience with fusidic acid prior to its belated introduction to Canada is reviewed. Fusidic acid is a steroid antibiotic with minimal toxic and hormonal effects that is mainly excreted through the liver. It has a predominantly bactericidal action and does not shown cross-resistance with other antibiotics. Since organisms resistant to this drug form easily in vitro when exposed to low concentrations, complementary treatment with another antibiotic may be required in some clinical situations. Although fusidic acid is active in vitro against a number of organisms, to date it has mainly been used to treat serious infections due to Staphylococcus aureus. The agent appears to be particularly valuable in the treatment of bone and joint infections and in pediatric practice. Fusidic acid will soon be available in Canada for both oral and intravenous administration. Attainable antibiotic levels in many tissues and body fluids greatly exceed the minimum inhibitory concentrations.