Soluble Guanylate Cyclase Stimulators (SGCSs)

What are SGCSs?

SGCSs are a type of targeted therapy used to treat people with PH. They are also the first targeted therapy to be shown to be effective in Chronic Thromboembolic Pulmonary Hypertension (CTEPH).  Targeted therapies slow the progression of PH/CTEPH.  The dose is the same for both conditions.

At the moment, the only medicine in this class are tablets called Riociguat (Adempas)

How do SGCSs work?

SGC is an substance produced in the body that causes the blood vessels in the lungs to dilate (become wider).   The mechanism for this is similar to the PDE5 inhibitors, so these two classes or medicine will never be taken together.

How are SGCSs started?

In the clinical trial, nearly all the patients increased to a dose of 2.5mg three times daily.  However the starting dose is 1mg three times daily and the amount taken is increased slowly over a few weeks.  Patients receive specialist support, management and training to get to their appropriate dose.  This steady dose increase process is usually called dose titration.  Sometimes Riociguat can drop the blood pressure so during the titration phase, so patients need to measure their own blood pressure.  This measurement can be done easily at home with home blood pressure monitoring equipment.   Once patients get to their maximum dose, no on-going monitoring or blood tests are needed.

Your PH specialist team will ensure you have all the information and training you need.

Risks associated with taking SGCSs

Like all medicines, SGCSs are associated with some risks.  However, problems are usually temporary, and wear off quickly once your body gets used to the new medicine.  These are very similar to what we expect with PDE5s, so headache, flushing and lightheadedness due to low blood pressure.  For this reason, most people are given their first dose at the hospital so these side effects can be monitored and managed accordingly.  Following a successful first dose, patients titrate their dose as described above.  In addition to blood pressure issues, other common side effects include nasal stuffiness and mild GI disturbances.

PDE 5 inhibitors are known to interact with certain types of medicine. Your PH specialist will discuss the types of drugs you should avoid if you are taking PDE 5 inhibitors.

Your PH team will discuss all the risks associated with taking PDE 5 inhibitors with you.