IV-to-Oral Switch in Antimicrobial Therapy for Hospitalised Adults: A PRISMA-Compliant Systematic Review of Indications, Agents, and Outcomes

This systematic review examines the evidence and guidelines for IV-to-oral switch (IVOS) in antimicrobial therapy for hospitalised adults. Following PRISMA 2020 methodology, we synthesised data from randomised controlled trials, observational studies, and stewardship guidance documents. Key findings from landmark trials (OVIVA, POET, SABATO, CAP studies) demonstrate that early oral switch is safe, effective, and reduces hospital stay by 2–5 days without increasing relapse or mortality, provided patients meet clinical stability and source control criteria. We also compared international stewardship recommendations, including IDSA/SHEA, UK National IVOS programme, and HSE AMRIC 2025 toolkit, which converge on consistent eligibility criteria. The review concludes that IVOS should be standard practice in clinically stable adults when suitable oral options exist, with exceptions for uncontrolled sepsis, endocarditis without stabilisation, CNS infections, and cases lacking bioavailable oral agents.