Based on theoretical considerations darunavir/cobicistat is expected to increase quetiapine plasma concentrations (CYP3A, CYP2D6 and/or P-gp inhibition). The combination of quetiapine and darunavir/cobicistat is contraindicated due to the potential for serious and/or life-threatening adverse reactions 

Coadministration is expected to increase concentrations of quetiapine. Initiation of darunavir/cobicistat in patients taking quetiapine: Consider alternative antiretroviral therapy to avoid increases in quetiapine exposure. If co-administration is necessary, reduce the quetiapine dose to 1/6 of the current dose and monitor for quetiapine-associated adverse reactions. Refer to the quetiapine prescribing information for recommendations on adverse reaction monitoring. Initiation of quetiapine in patients taking darunavir/cobicistat: Refer to the quetiapine prescribing information for initial dosing and titration of quetiapine.