To the Editor.
—For the initial treatment of tuberculosis (TB), Mahmoudi and Iseman1 recommend a four-drug regimen that includes ethambutol. The Centers for Disease Control and Prevention (CDC) have recently and similarly recommended that initial TB treatment consist of four drugs including either ethambutol or streptomycin.2 These revised recommendations for initial treatment have been made in an attempt to control multidrug-resistant TB, with the assumption that the drugs are relatively safe.Ethambutol's major toxic effect is retrobulbar optic neuritis, which is said to occur infrequently. At daily dosages of 25 mg/kg, the published incidence of ethambutol-associated optic neuritis (EAON) is 5%; for daily dosages of 15 mg/kg, the incidence is less than 1%.3We provide state-funded TB treatment for persons in 26 Texas Panhandle counties and use ethambutol infrequently. We reviewed records of our patients who had received ethambutol during the previous 24 months. Patients with human
Pierce JR, Denison AV. Treating Multidrug-Resistant Tuberculosis: Compliance and Side Effects. JAMA. 1994;271(2):104-105. doi:10.1001/jama.1994.03510260027018