Treatment algorithm for tuberculosis Treatment algorithm for tuberculosis. Patients in whom tuberculosis is proven or strongly suspected should have treatment initiated with isoniazid (INH), rifampin (RIF), pyrazinamide (PZA), and ethambutol (EMB) for the initial 2 months. A repeat smear and culture should be performed when 2 months of treatment has been completed. If cavities were seen on the initial chest radiograph (CXR) or the acid-fast bacillus (AFB) smear results are positive at completion of 2 months of treatment, the continuation phase of treatment should consist of INH and RIF daily or twice daily for 4 months to complete a total of 6 months of treatment. If cavitation was present on the initial CXR and the culture results at the time of completion of 2 months of therapy are positive, the continuation phase should be lengthened to 7 months (total of 9 months of treatment). If the patient has HIV infection and the CD4+ cell count is <100/μL, the continuation phase should consist of daily or three times weekly INH and RIF. In HIV-uninfected patients with no cavitation on CXR and negative results on AFB smears at completion of 2 months of treatment, the continuation phase may consist of either once weekly INH and rifapentine (RPT) or daily or twice weekly INH and RIF to complete a total of 6 months of treatment (bottom). For patients receiving INH and RPT whose 2-month culture results are positive, treatment should be extended by an additional 3 months (total of 9 months). *EMB may be discontinued when results of drug susceptibility testing indicate no drug resistance. †PZA may be discontinued after it has been taken for 2 months (56 doses). ‡RPT should not be used in HIV-infected patients with tuberculosis or in patients with extrapulmonary tuberculosis. §Therapy should be extended to 9 months if results of 2-month culture are positive. (Reproduced with permission of the American Thoracic Society. Copyright © American Thoracic Society. Blumberg HM, et al. American Thoracic Society/Centers for Disease Control and Prevention/Infectious Diseases Society of America: Treatment of tuberculosis. Am J Respir Crit Care Med. 2003;167:603.) Source: Chest Wall, Lung, Mediastinum, and Pleura, Schwartz's Principles of Surgery, 10e Citation: Brunicardi F, Andersen DK, Billiar TR, Dunn DL, Hunter JG, Matthews JB, Pollock RE. Schwartz's Principles of Surgery, 10e; 2014 Available at: http://accessmedicine.mhmedical.com/DownloadImage.aspx?image=/data/books/980/bru_ch19_f032.png&sec=100395786&BookID=980&ChapterSecID=59610861&imagename= Accessed: November 13, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved