CLARITHROMYCIN IS INACTIVE AGAINST MYCOBACTERIUM-TUBERCULOSIS

When 10% oleic acid-albumin dextrose-catalase-enriched Mueller-Hinton agar medium was employed, the MICs of clarithromycin (CLARI) at,which 50 and 90% of 12 strains of Mycobacterium tuberculosis were inhibited were 64 and >128 mu g/ml, respectively, which are significantly greater than the achievable peak CLARI concentrations in serum and in lung tissue in humans. In two different mouse experiments, 4 to 6 weeks of treatment with CLARI at 200 mg/kg of body weight six times weekly produced neither bactericidal nor bacteriostatic effects against M. tuberculosis. Therefore, we conclude that CLARI as a single drug is inactive against M. tuberculosis.