From the Research
The recommended dose of dapsone for Pneumocystis jirovecii pneumonia (PCP) prophylaxis is 100 mg orally once daily or 50 mg orally twice daily. Dapsone is a second-line agent for PCP prophylaxis, typically used in patients who cannot tolerate trimethoprim-sulfamethoxazole (TMP-SMX), which remains the first-line agent. Before starting dapsone, patients should be screened for glucose-6-phosphate dehydrogenase (G6PD) deficiency, as dapsone can cause hemolytic anemia in G6PD-deficient individuals 1. Dapsone works by inhibiting folic acid synthesis in Pneumocystis organisms through inhibition of dihydropteroate synthase. Common side effects include rash, nausea, and methemoglobinemia. Patients should be monitored for anemia, methemoglobinemia, and hepatotoxicity while on dapsone therapy. The medication should be taken with food if gastrointestinal upset occurs.
Some key points to consider when using dapsone for PCP prophylaxis include:
- The efficacy of dapsone in preventing PCP has been demonstrated in several studies, including a comparative trial of dapsone versus trimethoprim/sulfamethoxazole for primary prophylaxis of PCP 2.
- Dapsone can be used in combination with pyrimethamine and leucovorin as an alternative regimen for PCP prophylaxis.
- The safety and efficacy of dapsone in children have been evaluated in a randomized, multicenter trial, which found that daily and weekly dapsone regimens had similar efficacy and toxicity profiles 3.
- Dapsone can cause a range of adverse effects, including rash, anemia, methemoglobinemia, and hepatotoxicity, and patients should be monitored closely for these effects while on therapy 4, 5.
Overall, dapsone is a useful alternative for PCP prophylaxis in patients who cannot tolerate TMP-SMX, and its efficacy and safety have been demonstrated in several studies.