• Pulmonary hypertension

Opsumit Generic Name & Formulations

General Description

Macitentan 10mg; tabs.

Pharmacological Class

Endothelin receptor antagonist.

How Supplied

Tabs—15, 30

Generic Availability


Mechanism of Action

Macitentan inhibits the binding of endothelin (ET)-1 to both ETA and ETB receptors. Macitentan displays high affinity and sustained occupancy of the ET receptors in human pulmonary arterial smooth muscle cells. One of the metabolites of macitentan is also pharmacologically active at the ET receptors and is estimated to be about 20% as potent as the parent drug in vitro. The clinical impact of dual endothelin blockage is unknown.

Opsumit Indications


Treatment of pulmonary arterial hypertension (PAH, WHO Group I) to reduce disease progression risks and hospitalization for PAH.

Opsumit Dosage and Administration


10mg once daily. Doses >10mg once daily: not recommended.


Not established.

Opsumit Contraindications



Opsumit Boxed Warnings

Boxed Warning

Embryo-fetal toxicity.

Opsumit Warnings/Precautions


Embryo-fetal toxicity: in females of reproductive potential, exclude pregnancy prior to initiation, monthly during, and for 1 month after treatment discontinuation; must use acceptable methods of contraception. Obtain LFTs prior to initiation and repeat during treatment as clinically indicated. Discontinue if clinically relevant ALT/AST elevations or if elevations accompanied by bilirubin >2×ULN, or by symptoms of hepatotoxicity occur. Underlying left ventricular dysfunction: monitor for fluid retention; evaluate if develops. Severe anemia: not recommended. Measure Hgb prior to initiation and repeat during treatment as clinically indicated. Consider pulmonary veno-occlusive disease if signs of pulmonary edema occur; discontinue if confirmed. Potential decrease in sperm count; counsel men on fertility effects. Nursing mothers: not recommended.



Opsumit Pharmacokinetics


  • Maximum plasma concentration: ~8 hours after oral administration.


  • >99% plasma protein bound.

  • Apparent volume of distribution: ~50 L.


  • CYP3A4 (primarily) with minor contributions of CYP2C8, CYP2C9, and CYP2C19. 


  • Renal (50%), fecal (24%). Half-life: ~16 hours.

Opsumit Interactions


Potentiated by strong CYP3A4 inhibitors (eg, ketoconazole, ritonavir); avoid concomitant use. May be potentiated by moderate dual or combined CYP3A4 and CYP2C9 inhibitors (eg, fluconazole, amiodarone); avoid concomitant use. Antagonized by strong CYP3A4 inducers (eg, rifampin); avoid concomitant use.

Opsumit Adverse Reactions

Adverse Reactions

Anemia, nasopharyngitis/pharyngitis, bronchitis, headache, influenza, urinary tract infection; hepatotoxicity, decreased hemoglobin.

Opsumit Clinical Trials

See Literature

Opsumit Note


For all female patients: available only through the Opsumit REMS program. To enroll call (866) 228-3546 or www.OpsumitREMS.com.

Opsumit Patient Counseling

See Literature