Based on theoretical considerations (systemic) dexamethasone is expected to decrease darunavir and/or cobicistat plasma concentrations (CYP3A induction). Systemic dexamethasone should be used with caution when combined with darunavir/cobicistat.

Coadministration is expected to decrease concentrations of darunavir and cobicistat and to increase concentrations of dexamethasone. Co-administration with systemic dexamethasone may result in loss of therapeutic effect and development of resistance to darunavir/cobicistat. Consider alternative corticosteroids. Co-administration with corticosteroids of which exposures are significantly increased by strong CYP3A inhibitors can increase the risk for Cushing’s syndrome and adrenal suppression. Alternative corticosteroids including beclomethasone and prednisolone (for which PK and/or PD are less affected by strong CYP3A inhibitors relative to other steroids) should be considered, particularly for long term use.