Standard Treatment for Drug-Susceptible Tuberculosis

Introduction to Standard Regimen

The British Medical Research Council conducted a series of controlled trials between 1946 and 1986 that established the standard 6-month regimen for drug-susceptible tuberculosis, which consists of an intensive phase of 2 months with rifampin, isoniazid, and pyrazinamide, followed by a continuation phase of 4 months with rifampin and isoniazid, as recommended by the British Medical Research Council 1
The World Health Organization conditionally recommends a 4-month regimen using rifapentine, isoniazid, pyrazinamide, and moxifloxacin for eligible patients aged 12 years and older with pulmonary DS-TB, based on the Study 31/A5349 trial 1, 6

The established standard regimen consists of an initial phase (first 2 months) with daily rifampin, isoniazid, pyrazinamide, and ethambutol, followed by a continuation phase (next 4 months) with daily rifampin and isoniazid, as recommended by the American Thoracic Society 2, 3
Ethambutol can be omitted in the initial phase for patients with a low risk of isoniazid resistance, according to the Centers for Disease Control and Prevention 2

For TB meningitis and CNS tuberculosis, treatment should be extended to 12 months total (2 months HRZE followed by 10 months HR), as recommended by the Infectious Diseases Society of America 2
If pyrazinamide cannot be included in the initial regimen, treatment duration should be extended to 9 months total, based on guidelines from the European Respiratory Society 4
For patients with isoniazid-resistant TB, a regimen of rifampin, ethambutol, and pyrazinamide for 6 months with the addition of a fluoroquinolone is suggested, according to the American College of Chest Physicians 8

Rifampin interacts with many medications, including oral contraceptives, anticoagulants, and antiretroviral drugs, requiring careful medication review, as recommended by the National Institutes of Health 4
Ethambutol should be used with caution in children whose visual acuity cannot be monitored, according to the Pediatric Infectious Diseases Society 7