A Feasibility Study Assessing Tolerability of Daily versus Twice Weekly Trimethoprim-Sulfamethoxazole Regimen for Prophylaxis against Pneumocystis Pneumonia in Patients with Systemic Autoimmune Diseases on Glucocorticoid Therapy

Abstract

Objective: To determine the feasibility of low-dose, intermittent administration of trimethoprim-sulfamethoxazole (TMP/SMX) for prophylaxis against pneumocystis pneumonia (PCP) in patients with systemic autoimmune diseases receiving medium- to high-dose glucocorticoid therapy.
Methods: A randomized prospective study was performed. Patients who were scheduled to receive medium- to high-dose glucocorticoid therapy were selected and randomly allocated to one of two groups: one group received 1 tablet of TMP/SMX (TMP 80 mg and SMX 400 mg) daily and the other group received 1 tablet twice a week. The observation period was up to one year, or until the prophylactic therapy was discontinued because of steroid tapering or occurrence of adverse events (AEs). The endpoint was occurrence of PCP, and safety was also assessed.
Results: Thirty-seven patients were enrolled in this study, with 19 patients assigned to the daily regimen and 18 to the twice weekly regimen. One patient in each group withdrew before starting treatment. None of the patients who entered this study developed PCP. Safety analysis showed fewer AEs with the twice weekly regimen than with the daily regimen (5 of 17 patients (29.4%) vs. 10 of 18 patients (55.6%), p＝0.176).
Conclusion: From this pilot study, twice weekly TMP/SMX prophylaxis seems to be more tolerable than daily dosing in patients with systemic autoimmune diseases receiving medium- to high-dose glucocorticoid therapy. Since the number of patients was insufficient, further study is necessary to determine the optimal regimen for PCP prevention in these patients.