Penetration of antitubercular drugs in clinical osteoarticular tubercular lesions.

In 79 consecutive cases of skeletal tuberculosis the concentration of streptomycin and ethambutol was analysed. The material for analysis was obtained from the diseased joints of 14 patients and from cold abscesses from spinal or osseous lesions in 65 patients. The concentration of the drugs in the serum and in the tuberculous material was measured 3 hours after the systemic administration of the drugs in therapeutic doses. The concentration was expressed as microgram per ml of the tuberculous material and the data were subjected to statistical analysis. Streptomycin and ethambutol penetrated freely into the tuberculous joints; their concentration in the cold abscesses, however, was half to one third of the concentration in the serum. There was a wide range of concentrations; however, in the tuberculous joints as well as in the cold abscesses the concentrations were much higher than those considered to have an inhibitory effect on mycobacterium tuberculosis in clinical material.