Table 3.

Dosages, mechanism of action, and clinical uses of the three antibiotics approved for CDI in IBD. IV—intravenous.

	Dosages	Mechanism of Action	Clinical Uses in CDI
Fidaxomicin	200 mg twice daily for 10 days per os, with or without	inhibition of RNA synthesis	No-fulminant episodes
Vancomycin	from 125 mg to 500 mg four times daily for 10–14 days per os	inhibition of bacterial cell wall synthesis	No-fulminant episodes Combined to metronidazole IV during fulminant episode without ileus
Metronidazole	500 mg three times daily for 10–14 days per os/IV	inhibition of nucleic acid synthesis	Per os if alternative agents are unavailable for unsevere episodes Intravenously Combined to Vancomycin during fulminant episode without ileus