Continuous cefazolin infusion versus cefazolin plus probenecid for the ambulatory treatment of uncomplicated cellulitis: A retrospective cohort study.

Background: The preferred ambulatory IV therapy for cellulitis is often once-daily cefazolin combined with once-daily oral probenecid (C+P). However, due to a national probenecid drug shortage in 2011, our centre developed a replacement protocol for the administration of cefazolin continuous infusion (CCI) using elastomeric infusers. Our goal was to compare treatment efficacy, duration of IV therapy, and recurrence associated with CCI and C+P using retrospective data from our centre.

Methods: We conducted a non-inferiority single-centre retrospective cohort study of emergency department medical records. Patients received either C+P (cefazolin 2 g IV once daily plus probenecid 1 g PO once daily) or CCI (cefazolin 2 g IV loading dose, followed by cefazolin 6 g IV via continuous infusion over 24 hours, via an elastomeric infuser). We compared treatment efficacy, duration of IV therapy, and recurrence rates.

Results:  total of 203 patients were analyzed, with 107 included in the CCI arm and 96 in the C+P arm. Overall, CCI users and C+P users were comparable in their sociodemographic and clinical variables measured at admission. We observed increased odds of achieving successful treatment among the CCI group, however it did not reach statistical significance (odds ratio [OR] 2.25; 95% CI 0.84 to 6.07). Recurrence rates were similar between both groups (OR 1.91; 95% CI 0.32 to 11.31). The average duration of IV therapy was similar between groups (p = 0.6).

Conclusions: ith results suggesting that CCI was non-inferior to C+P, and that both approaches required similar treatment durations, CCI could represent an acceptable alternative to C+P for the ambulatory IV treatment of cellulitis.