Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
Rifampin may change how your liver processes bosentan or macitentan.
What might happen:
If you are on bosentan, at first, the amount of bosentan in your blood may increase and cause more side effects than normal; however, after a few days, the amount of bosentan in your blood may decrease and it may not work as well.If you are on macitentan, the amount of macitentan in your blood may decrease and it may not work as well.
What you should do about this interaction:
Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together.If you are taking bosentan, your doctor may want to run tests to check your liver more often while you are taking rifampin. If you have any headaches, nausea, vomiting, fever, unusual tiredness, abdominal pain, or yellowing of the skin or whites of your eyes, contact your doctor. If you notice any change in your condition such as shortness-of-breath, increased weakness, or feeling like you might pass out, contact your doctor right away.If you are taking macitentan and notice any change in your condition such as shortness-of-breath, increased weakness, or feeling like you might pass out, contact your doctor right away.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.van Giersbergen PL, Treiber A, Schneiter R, Dietrich H, Dingemanse J. Inhibitory and inductive effects of rifampin on the pharmacokinetics of bosentan in healthy subjects. Clin Pharmacol Ther 2007 Mar;81(3):414-9.
2.Opsumit (macitentan) prescribing information. Actelion Pharmaceuticals US, Inc. October, 2013.
3.Tracleer (bosentan) US prescribing information. Actelion Pharmaceuticals US, Inc. October, 2012.
4.Bruderer S, Aanismaa P, Homery MC, Hausler S, Landskroner K, Sidharta PN, Treiber A, Dingemanse J. Effect of cyclosporine and rifampin on the pharmacokinetics of macitentan, a tissue-targeting dual endothelin receptor antagonist. AAPS J 2012 Mar;14(1):68-78.