Drug Interaction Report

Coadministration with inhibitors of CYP450 3A4 may increase the plasma concentrations of retapamulin, which is primarily metabolized by the isoenzyme. In healthy adult males, coadministration of the potent CYP450 3A4 inhibitor ketoconazole (200 mg orally twice a day) increased the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of retapamulin by 81% following topical application of retapamulin ointment 1% on abraded skin. However, dosage adjustments are not necessary due to the low systemic exposure to retapamulin following topical application.

Coadministration with inhibitors of CYP450 3A4 may increase the plasma concentrations of retapamulin, which is primarily metabolized by the isoenzyme. In healthy adult males, coadministration of the potent CYP450 3A4 inhibitor ketoconazole (200 mg orally twice a day) increased the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of retapamulin by 81% following topical application of retapamulin ointment 1% on abraded skin. However, dosage adjustments are not necessary due to the low systemic exposure to retapamulin following topical application.

ADJUST DOSING INTERVAL: Food enhances the absorption and oral bioavailability of darunavir administered in combination with low-dose ritonavir. The mechanism is unknown. When administered with food, the peak plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC) of darunavir were approximately 30% higher than when administered in the fasting state. Darunavir exposure was similar for the range of meals studied. The total caloric content of the various meals evaluated ranged from 240 Kcal (12 grams fat) to 928 Kcal (56 grams fat).

MANAGEMENT: To ensure maximal oral absorption, darunavir coadministered with ritonavir should be taken with food. The type of food is not important.