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(macitentan) Tablets



  • Do not administer OPSUMIT to a pregnant female because it may cause fetal harm [see CONTRAINDICATIONS, WARNINGS AND PRECAUTIONS, Use in Specific Populations].
  • Females of reproductive potential: Exclude pregnancy before the start of treatment, monthly during treatment, and 1 month after stopping treatment. Prevent pregnancy during treatment and for one month after stopping treatment by using acceptable methods of contraception [see Use in Specific Populations].
  • For all female patients, OPSUMIT is available only through a restricted program called the OPSUMIT Risk Evaluation and Mitigation Strategy (REMS) [see WARNINGS AND PRECAUTIONS].


OPSUMIT (macitentan) is an endothelin receptor antagonist. The chemical name of macitentan is N-[5-(4-Bromophenyl)-6-[2-[(5-bromo-2-pyrimidinyl)oxy]ethoxy]-4-pyrimidinyl]-N'propylsulfamide. It has a molecular formula of C19H20Br2N6O4S and a molecular weight of 588.27. Macitentan is achiral and has the following structural formula:

OPSUMIT® (macitentan) Structural Formula Illustration

Macitentan is a crystalline powder that is insoluble in water. In the solid state macitentan is very stable, is not hygroscopic, and is not light sensitive.

OPSUMIT is available as a 10 mg film-coated tablet for once daily oral administration. The tablets include the following inactive ingredients: lactose monohydrate, magnesium stearate, microcrystalline cellulose, polysorbate 80, povidone, and sodium starch glycolate Type A. The tablets are film-coated with a coating material containing polyvinyl alcohol, soya lecithin, talc, titanium dioxide, and xanthan gum.

Last reviewed on RxList: 3/30/2017
This monograph has been modified to include the generic and brand name in many instances.

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