Antibiotic route and duration of therapy for cellulitis: data extracted from a multi-center clinical trial

Introduction: Although cellulitis is a relatively common condition, there is uncertainty about the benefit of intravenous (IV) over oral (PO) antibiotic therapy, and the appropriate duration of treatment. Methods: Data extracted from a clinical trial (NCT01876628) of antibiotic therapy for cellulitis were used to assess the association between the route of administration and duration of treatment, and clinical outcome. Results: Of 323 patients with antibiotic data, 114 received some IV therapy. IV antibiotic therapy was preferred in those who had received antibiotics prior to trial entry (P < 0.001). Patients characterised as having more severe cellulitis (C-reactive protein > 100 mg/L, affected skin surface area > 5% or systemic inflammatory response syndrome score ≥ 1) were more likely to have had IV therapy. Those given only PO therapy were more likely to have improved at day 5 compared with those given at least a single dose of IV therapy (P = 0.015), and were as likely to be back to their normal activities at day 10 (P = 0.90), and day 30 (P = 0.86). There was no association between initial severity and the duration of antibiotic therapy given within the trial. There was no association between duration of antibiotic therapy and outcome as measured at day 10 and day 30. Conclusions: This study provides evidence that recovery is not associated with the route of antibiotic administration for patients with cellulitis of similar severity, or that a course length of > 5 days results in any additional benefit.