Coadministration with indinavir/ritonavir has not been studied. Coadministration of emtricitabine or tenofovir-DF with indinavir alone showed no clinically significant interactions. Indinavir in combination with emtricitabine resulted in no change in AUC or Cmax of either drug. Coadministration of tenofovir-DF (300 mg once daily) and indinavir (800 mg three times daily for 7 days) resulted in no change in AUC or Cmin of tenofovir and a 14% increase in Cmax. There was no change in indinavir AUC or Cmin, and an 11% decrease in Cmax. A higher risk of renal impairment has been reported in patients receiving tenofovir-DF in combination with a ritonavir boosted protease inhibitor. Close monitoring of renal function is required in these patients.