Coadministration has not been studied. Tamsulosin is metabolised mainly by CYP3A4 and to a lesser extent by CYP2D6. Coadministration with darunavir/cobicistat may increase tamsulosin exposure. Given tamsulosin’s higher affinity for alpha-1A receptors located in prostatic smooth muscle and its demonstrated tolerability when combined with other CYP3A4/CYP2D6 inhibitors, consider starting tamsulosin at 0.4 mg/day if coadministered. Blood pressure monitoring is recommended, particularly in older individuals. Emtricitabine and tenofovir alafenamide do not interact with this metabolic pathway