Comparison of adverse events between oral and intravenous formulations of antimicrobial agents: a systematic review of the evidence from randomized trials.

BACKGROUND Some clinicians may favor a strategy of early switch to oral antimicrobial therapy for patients responding to initial intravenous therapy. An important relevant consideration refers to the comparative safety and tolerability between oral and intravenous antimicrobial therapy. LITERATURE SEARCH/STUDY SELECTION: We sought to evaluate the above-mentioned issue by performing a systematic review of randomized studies comparing the occurrence of adverse events between oral and intravenous antimicrobial therapy with the same agents. FINDINGS Ten relevant studies (five randomized controlled trials, three randomized cross-over studies, and two randomized, placebo-controlled, parallel-design studies) were included. Seven of the studies evaluated antibacterials (fluoroquinolones in four, and telithromycin, amoxicillin-clavulanic acid, and linezolid in one study each, respectively), whereas two studies evaluated ganciclovir, and one evaluated isavuconazole. No difference was observed in the rate of total adverse events between oral and intravenous administration of the same antimicrobial agents in any of the included studies that reported specific relevant data. Injection site reactions were noted more frequently with intravenous treatment in one study. No serious drug-related adverse events were reported, while study withdrawals due to adverse events did not considerably differ between the compared groups in any of the included studies. CONCLUSION There are only limited comparative data regarding the adverse events associated with the administration of the same antimicrobial agents by the oral and intravenous route. Our review indicates that the adverse event profile of oral and intravenous antimicrobial therapy does not differ considerably; however, this issue requires validation by further studies.