Drug Interactions Updated for Two HIV Meds
The Food and Drug Administration (FDA) has approved labeling changes for two HIV medications: Stribild (elvitegravir 150mg, cobicistat 150mg, emtricitabine 200mg, tenofovir disoproxil fumarate 300mg tablets) and Tybost (cobicistat tablets).
Specifically, the Drug Interactions section has been updated to include revised information on concomitant use of corticosteroids with these drugs. For patients prescribed Stribild, coadministration with oral dexamethasone or other systemic corticosteroids that induce CYP3A may result in a loss of therapeutic effect and development of resistance to elvitegravir. As Tybost, a CYP3A inhibitor, is indicated to increase the systemic exposure of atazanavir and darunavir, coadministration with oral dexamethasone or other systemic corticosteroids that induce CYP3A may result in loss of therapeutic effect and development of resistance to atazanavir or darunavir.
In both these cases, an alternative corticosteroid should be considered. In addition, coadministration with corticosteroids whose 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 (whose pharmacokinetics and/or pharmacodynamics are less affected by strong CYP3A inhibitors relative to other studied steroids) should be considered, particularly for long-term use.
For more information visit FDA.gov.