ethambutol hydrochloride /eth′əmbyo̅o̅″təl/ , a tuberculostatic antibiotic. ▪ INDICATIONS: It is prescribed in the treatment of pulmonary tuberculosis in combination with other drugs. ▪ CONTRAINDICATIONS: Optic neuritis or known hypersensitivity to this drug prohibits its use. It is not recommended for small children. ▪ ADVERSE EFFECTS: Among the most serious adverse effects are diminished visual acuity and allergic reactions, such as rashes.