Bosentan levels go up with CYP3A4 inhibitors (such as ketoconazole, ritonavir and diltiazem), CYP2C9 inhibitors (such as amiodarone and fluconazole), and tacrolimus.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.