Bosentan levels in the blood can rise with CYP3A4 inhibitors (e.g. ketoconazole, ritonavir, diltiazem), CYP2C9 inhibitors (e.g. amiodarone, 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.