Opsumit is ONLY for Group 1, PAH. Group 2 is NOT PAH and cannot be given Opsumit which can cause heart attacks for Group 2 patients. Group 2 is PH, Left Heart Disease. Not all PH is PAH and the terms cannot be used interchangeably.

I personally know 2 people who had near disastrous results from being on Opsumit when they were actually Group 2. One had a heart attack, another went into a coma. I was lucky. I had been misclassified as Group 1 and was on Opsumit but then I was corrected to group 2, I was YANKED off of Opsumit in time.

Only Group 1 is PAH which is what Opsumit has been approved for.

Here's a cut and paste from the manufacturer's site: FC stands for Functional Class. and does not refer to a sub group

What is OPSUMIT® (macitentan)?
OPSUMIT® is a prescription medicine used to treat pulmonary arterial hypertension (PAH, WHO Group 1). PAH is high blood pressure in the arteries of your lungs. OPSUMIT® can:
Improve your ability to exercise as measured by the 6-minute walk distance (6MWD). In a clinical study of mainly WHO FC II-III patients, those taking OPSUMIT® walked, on average, 22 meters farther at Month 6 than patients taking a placebo (sugar pill)
Improve some of your symptoms
Help slow down the progression of your disease
Lower your chance of being hospitalized for PAH

I am group 1 and I am on opsumit.

Most side effects will lessen or go away within a few weeks. Be sure your care team knows anything you are experiencing.

Thank you

I have been on it 6 days and today am tired, slight headache, flu without the fever. How long do these symptoms last