The most significant risk factor for PCP prophylaxis is defect in cell-mediated immunity including high-dose glucocorticoid (HDGC, ≥20 mg of prednisone daily) treatment¹.  A systematic review concluded that at a PCP rate of 6.2% in control groups, PCP prophylaxis with trimethoprim/sulfamethoxazole (TMP/STX) is highly effective (85% risk reduction) in non-HIV patients with acute leukemia or solid organ/autologous bone marrow  transplantation (number needed to treat 19)².

Other Indications for PCP prophylaxis include¹:

1. HDGC treatment for ≥1month plus another cause of immunocompromise.
2. Combination of immunosuppressive drugs, such as tumor-necrosing factor- α inhibitors plus HDGC or other immunosuppression.
3. Polymyositis/dermatomyositis with interstitial pulmonary fibrosis on glucocorticoids.
4. Certain primary immunodeficiencies (eg idiopathic CD4-lymphopenia, hyper-IgM syndrome).
5. Granulomatosis with polyangiitis (Wegener’s) on methotrexate and HDGC
6. Rheumatologic diseases on HDGC and a second immunosuppressive drug
7. T-cell depleting agents (eg, fludarabine)
8. Severe malnutrition

TMP/STX may be given either as double-strength 3x/week or single-strength daily^1,2.

References

1. Anevlavis S, Kaltsas K, Bouros D. Prophylaxis for pneumocystis pneumonia (PCP) in non-HIV infected patients. PNEUMON 2012;25, October-December.
2. Stern A, Green H, Paul M, Leibovici L. Prophylaxis for pneumocystis pneumonia (PCP) in non-HIV immunocompromised patients (Review). Cochrane data of Systematic Reviews 2014, issue 10. DOI: 10.1002/14651858.CD005590.pub3.