DOSAGE AND ADMINISTRATION
In general, therapy should be continued until bacterial conversion and maximal improvement have occurred.
Adults: Two RIFAMATE (rifampin and isoniazid capsules USP) capsules (600 mg rifampin, 300 mg isoniazid) once daily, administered one hour before or two hours after a meal.
Concomitant administration of pyridoxine (B6) is recommended in the malnourished, in those predisposed to neuropathy (e.g., diabetic), and in adolescents.
Rifampin susceptibility powders are available for both direct and indirect methods of determining the susceptibility of strains of mycobacteria. The MIC's of susceptible clinical isolates when determined in 7H10 or other non-egg-containing media have ranged from 0.1 to 2 mcg/ml.
Quantitative methods that require measurement of zone diameters give the most precise estimates of antibiotic susceptibility. One such procedure has been recommended for use with discs for testing susceptibility to rifampin. Interpretations correlate zone diameters from the disc test with MIC (minimal inhibitory concentration) values for rifampin.