Which adverse effect is primarily associated with Ethambutol and requires patient education?

• A. Hearing loss
• B. Hepatotoxicity
• C. Renal failure
• D. Optic neuritis

Answer: (D)

Ethambutol is most associated with optic neuritis, an inflammation of the optic nerve that can cause blurred vision and deficits in color vision, especially red-green discrimination. Because these changes can become permanent if not detected early, patients must be educated to report any changes in vision promptly and to have baseline eye testing before starting therapy, with regular follow-up exams during treatment. If vision changes occur, stopping ethambutol is often necessary to prevent lasting damage. The drug is excreted by the kidneys, so renal function may require dose adjustments to minimize this risk. Other listed adverse effects like hearing loss, liver toxicity, or renal failure relate more to other TB drugs, not the primary issue with ethambutol.