Which tuberculosis medication has the most severe ocular side effects?

Which tuberculosis medication has the most severe ocular side effects?

• A. Rifampin
• B. Isoniazid
• C. Ethambutol
• D. Pyrazinamide

Answer: (C)

Ethambutol is known for causing optic neuritis, which presents as decreased visual acuity and color vision impairment (often red-green discrimination) that is dose- and duration-dependent. This makes it the anti-tuberculosis medication with the most notable and serious ocular toxicity. If caught early, stopping the drug can improve vision, but prolonged exposure can lead to permanent damage. Other standard TB drugs don’t have ocular toxicity as a prominent or dose-related risk. Rifampin can cause harmless orange discoloration of tears and urine and tends to injure the liver with other effects; isoniazid mainly causes neuropathies and hepatotoxicity rather than optic problems; pyrazinamide is associated more with hyperuricemia and liver toxicity.

Ethambutol is known for causing optic neuritis, which presents as decreased visual acuity and color vision impairment (often red-green discrimination) that is dose- and duration-dependent. This makes it the anti-tuberculosis medication with the most notable and serious ocular toxicity. If caught early, stopping the drug can improve vision, but prolonged exposure can lead to permanent damage.

Other standard TB drugs don’t have ocular toxicity as a prominent or dose-related risk. Rifampin can cause harmless orange discoloration of tears and urine and tends to injure the liver with other effects; isoniazid mainly causes neuropathies and hepatotoxicity rather than optic problems; pyrazinamide is associated more with hyperuricemia and liver toxicity.