Safety and Clinical Outcomes of Intravenous-to-Oral Antibiotic Switch Therapy in Patients with Brain Abscess: A Systematic Review

Abstract

Background: Brain abscess requires prolonged intravenous (IV) antibiotics, but early transition-to-oral-switch (IVOS) therapy may reduce hospital stay and healthcare burden. Evidence on safety, efficacy, and timing remains limited.

Methods: A systematic search of PubMed, Cochrane Central, ScienceDirect, and Taylor & Francis identified 67 studies; four met inclusion criteria, including 542 patients. Data on demographics, IV and oral antibiotic regimens, therapy duration, clinical outcomes, and adverse events were extracted.

Results: Patients were predominantly male (63–83.5%). IV antibiotics included β-lactams, metronidazole, thiophenicol, aminoglycosides, and penicillin derivatives, lasting 5–28 days. Oral regimens included fluoroquinolones, amoxicillin, rifampicin, clindamycin, cotrimoxazole, and nitroimidazoles. Total antibiotic duration ranged 36–140 days. IVOS was performed early (≤10 days) in 57% of patients in one study and after stabilization in others. Favorable outcomes (GOS 4–5) occurred in 61–82%. Mortality ranged 12–18.1%, mainly in severe cases. No abscess recurrence was reported at six months. Adverse events, mostly mild cytopenias, occurred in 25–76%; few required therapy modification. Early IVOS was associated with shorter hospitalization and fewer surgical revisions but was not an independent predictor of outcome.

Discussion: IVOS can be safely implemented in selected patients with brain abscess, potentially reducing hospital stay and healthcare costs. However, heterogeneity in timing and patient selection highlights the need for standardized protocol. GCS at admission and comorbidities remain the most important prognostic factors.

Conclusion: IVOS appears safe and effective, with potential additional benefits from early switch. Further research is needed to determine optimal timing and patient selection.