2026 Eastern States Conference

Title: Doxycycline vs azithromycin in combination with a beta-lactam for the treatment of community-acquired pneumonia in hospitalized patients 
Authors: Ashley Eadie, PharmD, Michael Parks, PharmD, BCPS 
Objective: Compare the impact of doxycycline vs azithromycin on hospital length of stay for the treatment of community-acquired pneumonia (CAP) 
Self-assessment Question: True/False - Doxycycline in combination with a beta-lactam is currently preferred for the treatment of CAP 
Background: Current preferred treatments for CAP include combination therapy with a beta-lactam and a macrolide or monotherapy with a respiratory fluoroquinolone. Doxycycline in combination with a beta-lactam is considered an alternative option. This study was designed to evaluate the effectiveness of doxycycline versus azithromycin for the management of CAP. 
Methods: This was a retrospective cohort study that included adult patients (≥18 years) hospitalized at Mary Washington Hospital with CAP, defined by primary diagnosis of CAP and chest radiographic evidence of pulmonary infiltrate within 48 hours of admission who received a beta-lactam plus either doxycycline or azithromycin for at least 48 hours. Exclusion criteria included patients that received both doxycycline and azithromycin during hospitalization, had respiratory comorbidities (e.g., chronic obstructive pulmonary disease, cystic fibrosis), were immunocompromised (e.g., active chemotherapy, HIV, history of transplant), had a diagnosis of COVID-19, were pregnant, had multiple sites of infection, were recently hospitalized (within 10 days), or were prisoners. The primary outcome was hospital length of stay. Secondary outcomes included escalation of antibiotics, total antibiotic duration, 30 day readmission, in-hospital mortality, and adverse effects, such as development of cardiac arrhythmias and esophagitis. 
Results: Among the 89 patients included, 79 were in the azithromycin group and 10 were in the doxycycline group. There was no statistical difference observed in the hospital length of stay between the azithromycin and doxycycline group (4.7 vs. 5.8 days; P=0.12). There was no statistical difference in escalation of antibiotics (P=0.32), total antibiotic duration (P=0.26), 30-day readmission (P=0.28), in-hospital mortality (P=0.72), development of arrhythmias (P=0.53) or development of esophagitis (P=1.0).  
Conclusion: Hospitalized patients with CAP who were treated with doxycycline vs azithromycin in combination with a beta-lactam showed no significant differences in primary or secondary outcomes. Larger, randomized, controlled trials are needed to further evaluate the effectiveness between the two groups.