Riociguat is a type of drug called a cyclic guanosine monophosphate stimulator. Cyclic CMP is produced in the lungs and other parts of the body in response to nitric oxide and causes arteries to relax and widen.

Riociguat further relaxes or widens those blood vessels in the lungs, which decreases pulmonary blood pressure and reduces stress on the right heart. Low lung pressures and improved right heart function help people with PAH and CTEPH be more active, as shown in research studies.

If your health care provider prescribes riociguat, you will take a pill three times a day, about six to eight hours apart (morning, midday and evening.) You can take it with or without food.

You also can crush the tablets and mix them water or soft food (such as applesauce) right before taking them.

Tablets are round and available in the following strengths:

• 5 mg (white)
• 1 mg (yellow-orange)
• 5mg (peach)
• 2 mg (orange)
• 5 mg (red)

The dose for this medication typically starts at 0.5 mg or 1 mg three times daily and increases by 0.5 mg every two to four weeks if you don’t have low blood pressure. The maximum dose is 2.5 mg, three times a day. Your doctor might lower the dose if your blood pressure falls significantly.

Dose interruption: If you stop taking riociguat for three days or more, your doctor likely will decrease your medicine to the original starting dose, then slowly increase to the maximum dose as tolerated.

Riociguat isn’t sold at local pharmacies. A specialty pharmacy selected by your insurance company will ship the medication to your home. Specialty pharmacies that dispense this medication include Accredo, CVS specialty and Kaiser Permanente.

Health care providers must enroll in a restricted distribution program to prescribe this therapy because of serious birth defect risks. The distribution program, called Risk Evaluation and Mitigation Strategy (REMS) for Adempas, is required by the FDA.

All women, regardless of pregnancy potential, must enroll in the Adempas REMS program before starting treatment. Women of reproductive potential must comply with monthly pregnancy testing and contraception requirements. Men don’t have to participate in the REMS program to receive riociguat.

Riociguat is generally well tolerated. No differences in side effects have been reported between men and women. The most frequent side effects are:

• Headache
• Upset stomach
• Dizziness
• Nausea
• Diarrhea
• Low blood pressure
• Vomiting
• Anemia
• Gastroesophageal reflux (heartburn)
• Constipation

Less frequent side effects include:

• Palpitations
• Nasal congestion
• Nosebleeds
• Difficulty swallowing
• Abdominal swelling
• Swelling in feet

Other side potential side effects:

Low blood pressure throughout the body. Use riociguat with caution if you take blood pressure medicine or other medications that might interact with riociguat, or if you have low systemic blood pressure.

Blood pressure monitoring when you start riociguat is necessary. It should be checked about every two weeks to help your doctor decide the best dose of riociguat for you.

Regular blood work for side effects isn’t required. As with all medicines, notify your doctor immediately if you experience serious side effects or symptoms that might be caused by riociguat.

Certain patient populations must take precautions while taking riociguat, while others should avoid it. Learn about who can and who shouldn’t take this medication:

Pregnant and breastfeeding patients

Riociguat can cause serious birth defects if taken during pregnancy. Women must not be pregnant when starting riociguat or become pregnant during treatment. Women must take monthly pregnancy tests to ensure they aren’t pregnant and use two forms of contraception when taking riociguat. One option is surgical treatment to prevent pregnancy, such as tubal ligation. Another is a copper T380A or LNg 20 intrauterine device.

It’s not known whether riociguat passes into breast milk. Nursing mothers shouldn’t use this drug.

Children and teens

The safety and effectiveness of riociguat for pediatric patients hasn’t been established.

People with other conditions

People with severe liver disease, severe kidney dysfunction and those on dialysis should avoid this drug.

Warning: Riociguat can cause fluid to build up in the lungs of people with pulmonary veno-occlusive disease. If that occurs, you might need to stop taking riociguat.

If you have dehydration, left heart disease or abnormalities of the nervous system, use this medication with caution.

Simultaneous use of riociguat with some medications can cause dangerous blood pressure drops. Don’t take riociguat if you use:

• Nitrates or nitric oxide donors.
• Phosphodiesterase inhibitors such as sildenafil, tadalafil or vardenafil.
• Non PH-treating phosphodiesterase inhibitors such as dipyridamole or theophylline.

Although riociguat and bosentan sometimes react slightly, you likely won’t need to adjust the doses of either PH drug.

Riociguat interacts with certain liver enzymes. Your provider might need to adjust your dose if you take ketoconazole, itraconazole or protease inhibitors for human immunodeficiency virus or AIDS. These medications can increase riociguat levels and cause more side effects, especially low blood pressure. You likely will need regular blood tests to monitor your liver enzymes.

Other considerations

Antacids containing magnesium or aluminum hydroxide (such as Maalox or Mylanta) can prevent riociguat from being absorbed. Don’t take antacids within an hour of taking riociguat.

Riociguat doesn’t affect warfarin levels.

Smoking can decrease the amount of riociguat in the body. Your doctor might need to adjust your dose. Smoking isn’t recommended for people with PAH.

Allergic reactions to this drug are possible, but not likely. Talk to your physician if you think you’re having an allergic reaction to treatment.

Tell your health care provider about all the medications you take, including over-the-counter drugs and herbal supplement, to avoid potential or known drug interactions.