Clostridium difficile associated diarrhoea; pseudomembranous colitis. May cause reddish urine discolouration. Monitor INR if coadministration w/ warfarin is necessary. Not recommended in concomitant use w/ other rifamycins. Concomitant use w/ P-gp eg, ciclosporin. Renal impairment. Severe (Child-Pugh C) hepatic impairment; model for end-stage liver disease score >25. Not recommended during pregnancy. Lactation. Ped patients <18 yr.