Ethambutol therapy requires regular monitoring of which system due to potential adverse effects?

• A. Eye exams
• B. Hearing tests
• C. Liver enzymes only
• D. Kidney function only

Answer: (A)

Ethambutol can cause optic neuritis, which affects vision and color perception. Because this toxicity can progress to permanent visual impairment if not detected early, regular eye examinations are essential during therapy. A baseline eye check before starting ethambutol and periodic visual acuity and color-vision testing throughout treatment help catch changes early and guide timely management, often involving stopping the drug. The other monitoring options aren’t the primary concern for this medication—hearing, liver enzymes, and kidney function are associated with other TB drugs or conditions, so eye exams are the most relevant protection against ethambutol’s adverse effects.