- P. jiroveci pneumonia (PCP) is the most common infection in patients with AIDS and is the leading cause of death in this population.
- TMP/SMX is the treatment of choice. The dosage is 5 mg/kg of the TMP component IV q6-8h for severe cases, with a switch to oral therapy when the patient's condition improves. Total duration of therapy is 21 days. Prednisone should be added if the patient has an arterial oxygen tension (PaO2) of <70 mm Hg or an alveolar-arterial oxygen gradient (P[A-a]O2) in excess of 35 mm Hg. The most frequently prescribed prednisone regimen is 40 mg PO bid on days 1-5 and 20 mg bid on days 6-10, followed by 20 mg daily on days 11-21. For patients who cannot receive TMP/SMX, the following alternatives are available:
- For mild to moderately severe disease (PaO2 >70 mm Hg or P[A-a]O2 <35 mm Hg).
- Trimethoprim, 20 mg/kg/d PO, and dapsone, 100 mg PO daily. Glucose 6-phosphate dehydrogenase deficiency should be ruled out before dapsone is used.
- Clindamycin, 600 mg IV or PO tid, plus primaquine, 15 mg PO daily. Glucose-6-phosphate-dehydrogenase deficiency should be ruled out before primaquine is used.
- Atovaquone, 750 mg PO tid. This drug should be administered with meals to increase absorption.
- For severe disease (PaO2 <70 mm Hg or P[A-a]O2 >35 mm Hg)
- Pentamidine, 4 mg/kg IV daily, should be infused over 2 hours. Hypoglycemia or hyperglycemia is common, and monitoring of glucose and serum electrolytes (including calcium) is essential. Nephrotoxicity, hematologic toxicity, and hypotension also are frequent.
- Trimetrexate, 45 mg/m2 IV daily over 90 minutes, and leucovorin, 20 mg/m2 IV or PO q6h, can be given.
- Prednisone taper should be added.
- Prophylaxis is indicated as described in the OI section. Secondary PCP prophylaxis can be discontinued if the CD4 count is >200 cells/microliter for more than 3 months as a result of ART treatment.