Drug Malabsorption and Resistant Tuberculosis in HIV-Infected Patients

To the Editor: Directly observed therapy for tuberculosis has been advocated as a way to improve compliance and control the emergence of drug resistance.1,2 We recently cared for two patients with human immunodeficiency virus (HIV) infection who were receiving therapy under direct observation when they relapsed with drug-resistant isolates of Mycobacterium tuberculosis, presumably due to subtherapeutic drug levels caused by malabsorption. Patient 1, a 30-year-old man, began receiving directly observed therapy in December 1993; his therapy consisted of isoniazid (300 mg), rifampin (600 mg), and pyrazinamide (800 mg) daily for ileocecal and pulmonary tuberculosis. At that time tuberculosis isolates . . .