Coadministration has not been studied. Amiodarone is metabolized by CYP2C8 and 3A4 and exposure may increase due to CYP3A4 inhibition by darunavir/cobicistat causing potential cardiac arrhythmias. The European SmPC for Symtuza contraindicates coadministration, but the US prescribing information advises caution and clinical monitoring.  [This interaction checker reflects the more cautious option.] Tenofovir alafenamide (the prodrug of tenofovir) is a substrate of P-gp and inhibitors of P-gp such as amiodarone are expected to increase the absorption of tenofovir alafenamide and thereby increase the systemic concentration. Emtricitabine does not interact with this metabolic pathway.