Bosentan and Mifepristone interaction
Bosentan and Mifepristone: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Bosentan (Tracleer) label · effective 2025-11-17
Co-administration of such combinations of a CYP2C9 inhibitor plus a strong or moderate CYP3A inhibitor with TRACLEER is not recommended.
Hormonal contraceptives: TRACLEER use decreases contraceptive exposure and reduces effectiveness ( 7.2 ).
Concomitant administration of both a CYP2C9 inhibitor (such as fluconazole or amiodarone) and a strong CYP3A inhibitor (e.g., ketoconazole, itraconazole) or a moderate CYP3A inhibitor (e.g., amprenavir, erythromycin, fluconazole, diltiazem) with TRACLEER will likely lead to large increases in plasma concentrations of bosentan.
An interaction study demonstrated that co-administration of bosentan and a combination oral hormonal contraceptive produced average decreases of norethindrone and ethinyl estradiol levels of 14% and 31%, respectively.
Effect of other drugs on bosentan Figure 1 Figure 2 7.2 Hormonal Contraceptives Hormonal contraceptives, including oral, injectable, transdermal, and implantable forms, may not be reliable when TRACLEER is co-administered.
From the Mifepristone label · effective 2025-09-25
CYP3A inducers: Do not use mifepristone with CYP3A inducers ( 7.3 ).
Avoid co-administration of mifepristone and CYP3A inducers such as rifampin, rifabutin, rifapentin, phenobarbital, phenytoin, carbamazepine, and St.
The dose of mifepristone should be limited to 900 mg, and strong inhibitors of CYP3A should be used only when necessary. [See Dosage and Administration ( 2.4 ), Warnings & Precautions ( 5.6 ), and Clinical Pharmacology ( 12.3 )] 7.3 CYP3A Inducers No medications that induce CYP3A have been studied when co-administered with mifepristone.
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.