Q. A 32-year-old man with a known history of AIDS and a Mycobacterium avium complex infection presents at your clinic for a routine follow-up. He has been undergoing treatment with anti-tubercular drugs for several weeks. His temperature is 98.6°F (37°C), pulse 80 beats per minute, blood pressure reading 120/80 mmHg, and respiratory rate 14 breaths per minute. His oxygen saturation on room air is 98%. During the examination, he exhibits an inability to differentiate between the colors red and green. Which of the following medications is most likely responsible for his current condition?