What is an alternative prophylaxis option for Pneumocystis jirovecii when TMP-SMX is not tolerated?

• A. Oral dapsone
• B. Acyclovir
• C. Fluconazole
• D. Levofloxacin

Answer: (A)

When TMP-SMX cannot be used for Pneumocystis prophylaxis, an oral dapsone option is commonly chosen because it has activity against Pneumocystis jirovecii and can be effective as an alternative preventive agent. Dapsone works differently from TMP-SMX but provides similar protection against Pneumocystis. Before starting, it’s important to check for G6PD deficiency, since dapsone can cause hemolysis and methemoglobinemia in deficiency. If G6PD is normal, dapsone can be used with monitoring for hematologic issues and hypersensitivity. Other alternatives exist, such as atovaquone or pentamidine, but they’re not as widely used or suitable for all patients. The remaining options listed—acyclovir, fluconazole, and levofloxacin—do not prevent Pneumocystis jirovecii infection, as they target herpesviruses, Candida, and bacteria, respectively.