Riociguat is used to treat high blood pressure in the lungs (pulmonary hypertension). It can also be used to treat a certain type of high blood pressure in the lungs caused by blood clots (chronic thromboembolic pulmonary hypertension) when surgery has not been fully successful or is impossible. Riociguat works by relaxing and widening the blood vessels in your lungs so blood can flow more easily. Decreasing high blood pressure in the lungs allows your heart and lungs to work better and improves your ability to exercise.

Read the Medication Guide and, if available, the Patient Information Leaflet provided by your pharmacist before you start taking riociguat and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

Take this medication by mouth with or without food as directed by your doctor, usually 3 times daily. The dosage is based on your medical condition, response to treatment, and other medications you may be taking. Be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Take this medication 1 hour before or after taking antacids that contain aluminum or magnesium. These products prevent your body from fully absorbing riociguat.

To reduce your risk of side effects (such as low blood pressure), your doctor may direct you to start this medication at a low dose and gradually increase your dose. Follow your doctor's instructions carefully.

Use this medication regularly to get the most benefit from it. To help you remember, take it at the same times each day.

Do not increase your dose or use this drug more often than prescribed. Your condition will not improve any faster, and your risk of side effects will increase.

Tell your doctor if your condition does not get better or if it gets worse.

Headache, dizziness, lightheadedness, fainting, unusual tiredness, heartburn, indigestion, nausea, vomiting, or diarrhea may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

This medication has rarely caused serious bleeding. If you notice any of the following unlikely but serious signs of bleeding, tell your doctor right away:

• unusual bleeding from the vagina
• coughing up blood
• bleeding around catheter site
• signs of stomach/intestinal bleeding (such as black/bloody stools, vomit that contains blood or looks like coffee grounds)
• signs of bleeding in the brain (such as severe headache, weakness on one side of the body, vision problems, trouble speaking, confusion)

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking riociguat, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• smoking or history of smoking
• low or high blood pressure
• other lung conditions (such as pulmonary veno-occlusive disease, idiopathic interstitial pneumonia)
• dehydration
• a severe blockage of blood flow out of the heart

This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

This medication must not be used during pregnancy. It may harm an unborn baby. See also Warning section.

It is unknown if this medication passes into breast milk. Consult your doctor before breastfeeding.

See also How To Use section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug include:

• aminophylline
• certain drugs used to treat chest pain/angina or high blood pressure (nitrates such as nitroglycerin, isosorbide)
• dipyridamole
• drugs to treat erectile dysfunction-ED/pulmonary hypertension (such as sildenafil, tadalafil, vardenafil)
• recreational drugs called "poppers" containing amyl or butyl nitrite
• theophylline
• vericiguat

Cigarette smoking decreases blood levels of this medication. Tell your doctor if you smoke or if you have recently stopped smoking.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Do not share this medication with others.

Lab and/or medical tests (such as blood pressure, pregnancy tests) must be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

If you miss a dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up. Check with your doctor if you miss doses for more than 3 days in a row.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.