Clinical pharmacological considerations in an early intravenous to oral antibiotic switch: are barriers real or simply perceived?

Background: Traditionally, there has been a common belief that ongoing i.v. antibiotic therapy is superior to an early i.v. to oral switch, especially for severe infections. However, this may be at least partly based on early observations rather than robust, high-quality data and contemporary clinical studies. It is important to examine whether these traditional views align with clinical pharmacological considerations, or conversely, if these considerations may support the broader application of an early i.v. to oral switch under appropriate circumstances. 

Objectives: To examine the rationale for an early i.v. to oral antibiotic switch in the context of clinical pharmacokinetic and pharmacodynamic principles and to discuss whether commonly encountered pharmacological barriers are real or simply perceived. 

Sources: We conducted PubMed searches on barriers and clinicians' perceptions about an early i.v. to oral switch, clinical studies comparing switching with i.v.-only dosing, and pharmacological factors affecting oral antimicrobials. 

Content: We focused on general pharmacological and clinical pharmacokinetic and pharmacodynamic principles and considerations that are relevant when clinicians ponder whether to switch from i.v. to oral antimicrobial dosing. The main focus of this review was on antibiotics. The discussion of the general principles is accompanied by specific examples from the literature. 

Implications: Clinical pharmacological considerations and an imposing and increasing number of clinical studies, including randomized clinical trials, support an early i.v. to oral switch for the treatment of a number of infection types, under appropriate circumstances. We hope that the information provided here will add to calls for a critical examination of the role of i.v. to oral switching for many infections that are currently treated almost exclusively with i.v.-only therapy, and that it will inform health policy and guideline development by infectious diseases organizations.