What is the recommended action if ethambutol-induced optic neuritis occurs during TB therapy?

• A. Continue ethambutol and monitor vision
• B. Stop ethambutol and switch to another effective regimen; reassess duration and regimen
• C. Stop all TB therapy permanently
• D. Increase ethambutol dose and continue

Answer: (B)

Ethambutol can cause optic neuritis, and this toxicity can progress to permanent vision loss if the drug is continued. The priority is to protect vision, so the correct action is to stop ethambutol immediately and switch to an alternative, effective TB regimen. This ensures you maintain TB control while removing the offending agent. After switching, the total duration and composition of therapy should be reassessed based on drug susceptibility, treatment response, and tolerability. Monitoring vision is important, and once the optic neuritis resolves, the team can decide on reintroduction of ethambutol (if still needed) or continuing with the alternative regimen. Continuing ethambutol with monitoring risks irreversible damage; stopping all TB therapy or increasing the dose would not be appropriate.