Treatment for an initial episode and a first recurrence of CDI: If oral therapy is possible: Nonsevere: metronidazole 500 mg three-times daily (t.i.d.) orally for 10 days; Severe: vancomycin 125 ...

Comparisons have been made between vancomycin dosage strengths and relative efficacies ... CDAD were randomized to receive either 125 or 500 mg of oral vancomycin four times daily for 10 days.