Ocular Manifestations of Ethambutol

Introduction Ethambutol* (2,2'-(ethylenediamino) di1-butanol) is an experimental drug which shows promise against resistant tubercle bacilli. It has been used experimentally in patients refractory to all other antituberculous medication. To date, 18 patients have been placed on the drug in various centers throughout the country. They received dosages varying from 60 to 100 mg. per kilogram body weight per day. Eight of these patients developed either mild or severe toxic amblyopia. The following case demonstrates the features of the ocular toxicity of ethambutol. Report of a Case The patient, a 49-year-old white male, was admitted on March 9, 1961, with tuberculosis resistant to streptomycin, isoniazid (INH), and aminosalicylic acid (PAS). He has been known to have diabetes since April, 1960. The patient smokes 1½ packages of cigarettes a day and is a chronic alcoholic. The past history is otherwise negative. Physical Examination. —Vital signs were normal. The trachea was deviated to