Table 2.

European society of clinical microbiology and infectious diseases.²¹

Clinical definition	Recommended treatment in adults
Initial, mild clearly induced by the use of antibiotics	Stop the inducing antibiotic. Observe patients closely for any signs of clinical deterioration and place on therapy immediately if this occurs.
Initial and first recurrence, non-severe	If oral therapy possible:
	Metronidazole, 500 mg TID orally for 10 days
	If oral therapy not possible:
	Metronidazole 500 mg TID intravenously for 10 days
Initial and first recurrence, severe	If oral therapy possible:
	Vancomycin, 125 mg QID orally for 10 days
	If oral therapy not possible:
	Metronidazole 500 mg TID intravenously for 10 days plus intracolonic vancomycin 500 mg in 100 ml of normal saline every 4–12 h and/or vancomycin 500 mg QID by nasogastric tube
Second and later recurrences	If oral therapy is possible:
	• Vancomycin 125 mg QID orally for at least 10 days
	• Consider a taper (for example, decreasing daily dose with 125 mg every 3 days)/pulse (e.g. a dose of 125 mg every 3 days for 3 weeks) strategy
	If oral therapy is impossible:
	• Metronidazole 500 mg TID intravenously for 10–14 days plus retention enema of vancomycin 500 mg in 100 ml of normal saline every 4–12 h and/or vancomycin 500 mg QID by nasogastric tube

QID, four times per day; TID, three times per day.