Riociguat

How it works

It is a soluble guanylate cyclase stimulator that acts both directly on the enzyme and by sensitising it to endogenous nitric oxide, raising cyclic GMP to relax pulmonary vascular smooth muscle.

Prescribing in practice

• Contraindicated in pregnancy and with concomitant phosphodiesterase type 5 inhibitors (such as sildenafil) or nitrates, because of the risk of profound, potentially fatal hypotension — pregnancy prevention measures are mandatory for women of childbearing potential.
• It is contraindicated in pulmonary hypertension associated with idiopathic interstitial pneumonias, and smoking lowers plasma levels so dose may need review if smoking status changes.
• Up-titrate gradually against systolic blood pressure and symptoms of hypotension, and avoid in severe hepatic impairment.

Monitoring

Monitor blood pressure during dose titration and at intervals thereafter, watching for symptomatic hypotension and haemoptysis or pulmonary haemorrhage.

Counselling the patient

• Effective contraception is essential and monthly pregnancy testing may be required.
• Never take with erectile dysfunction medicines or nitrates.
• Report dizziness, fainting or coughing up blood.

Evidence & guidelines

Efficacy in both pulmonary arterial and chronic thromboembolic pulmonary hypertension is supported by pivotal randomised trials and reflected in the SPC.