Investigation on the serum and lung tissue level of rifampicin in man.

After the oral administration of 600 mg rifampicin, we determined the rifampicin level of the lung tissue of 18 operated patients, as well as the rifampicin level of the pleural callus of one patient, that of the pericardial cyst of another, and the serum level of all the 20 patients. The serum level amounted to an average of 6.5 mcg/ml between 2 and 6hours after administration, and to 3.3 mcg/ml between 8 and 9 hours. The lung tissue level amounted to an average of 2.3 mcg/g. The lung rifampicin level reached 32-44-62 per cent of the serum level 2 to 9 hours after its administration. This concentration was found to meet treatment requirements of Mycobacterium tuberculosis, Gram-positive cocci, and certain Gram-negative bacteria-induced airway infections.