-Renal impairment In a multiple-dose study, 36 subjects with varying degrees of renal impairment, a 1.4-fold increase in Cmax, ss, and a 2-fold increase in AUC (0-24)ss at 800 mg multiple doses in the severe renally impaired group (CLCR < 30 mL/ min) compared to healthy volunteers were observed and a reduced dosage of Ketek is recommended (See Section 4.2.).