Coadministration has not been studied. Dexamethasone is metabolized by CYP3A4. Darunavir/cobicistat may increase dexamethasone concentrations due to inhibition of CYP3A4. A dose reduction of the glucocorticoid may be necessary with monitoring for symptoms of hypercorticism. Dexamethasone is a weak CYP3A4 inducer at a low dose and is unlikely to have a clinically significant effect on darunavir/cobicistat. No interaction is expected with emtricitabine. Although dexamethasone induces intestinal P-glycoprotein, low dose dexamethasone is not expected to significantly reduce absorption of tenofovir alafenamide. Note, it is expected that the risk of Cushing’s syndrome is less likely to occur when using dexamethasone at a low dose and for a short treatment duration as compared to higher doses and long treatment duration. Note, it is expected that the risk of Cushing’s syndrome is less likely to occur when using dexamethasone at a low dose and for a short treatment duration as compared to higher doses and long treatment duration.