Resistance to Isoniazid
The most common pattern of resistance is isolated resistance to isoniazid, which can be treated with rifampin, pyrazinamide and ethambutol for 6-9 months. A quinolone is often added if there is extensive disease; streptomycin is an alternative to ethambutol. Patients who cannot tolerate pyrazinamide can take rifampin and ethambutol for 12 months.