2025 Southeastern Residency Conference

Title: Outpatient Parenteral Antimicrobial Therapy Adverse Events for Daptomycin Compared to Vancomycin 


Authors: Kristin Lanier, Jaspaul Jawanda, Allison Cid


Background: Outpatient parenteral antimicrobial therapy (OPAT) is defined as the administration of two or more doses of a parenteral antimicrobial agent outside of the hospital setting. Two commonly used antibiotics are vancomycin and daptomycin for treating gram-positive infections. The administration time of vancomycin is dose dependent and requires monitoring to assess for toxicity and therapeutic response. Daptomycin is administered as an intermittent infusion or an intravenous push. While creatine kinase levels should be monitored, daptomycin does not routinely require therapeutic drug monitoring. In patients where use of either agent would be appropriate, the differences in adverse event rates are unclear. 


Methods: A retrospective chart review was conducted between September 1, 2023 through August 30, 2024 at a 400-bed community hospital. Patients that have been treated within the FirstHealth of the Carolinas hospitals and the FirstHealth Infectious Diseases Clinic, that received either vancomycin or daptomycin in the OPAT setting within the 12-month time frame were identified. Patients with end-stage renal disease requiring continuous renal replacement therapy, that died during OPAT, or were pregnant were excluded. Demographic and clinical data was abstracted from the electronic health record. All patient data was in encrypted files with access granted only to investigators. The primary outcome studied was the occurrence of an adverse drug event resulting in a change in antimicrobial therapy or early discontinuation of therapy due to harm or injury. The secondary outcomes included a measurement of time to adverse drug event occurrence and total number of adverse events. The primary outcome was analyzed utilizing a Chi-square test. 

Results: Within the study, a total of 175 patients were included with 112 in the daptomycin group and 63 in the vancomycin group. For the primary outcome of early discontinuation of OPAT therapy, there was no statistically significant difference between the daptomycin and vancomycin groups (0.13 vs. 0.14, P = 0.87). The primary reason for early discontinuation in both groups was the occurrence of an adverse event. The daptomycin group demonstrated a shorter time to adverse event occurrence compared to the vancomycin group (12 vs. 30 days).  

Conclusions: When comparing the rate of early discontinuation between daptomycin and vancomycin in the OPAT setting, there was no significant difference between groups. These findings suggest either agent may be considered in the OPAT setting depending on patient specific factors. It is likely that utilization of a Bayesian model dosing software in conjunction with a dedicated OPAT clinical pharmacist, resulted in a reduction of adverse events in the vancomycin group.