riociguat

Riociguat is a prescription medication classified as a soluble guanylate cyclase (sGC) stimulator. It is approved for the treatment of certain forms of pulmonary hypertension in adults, including pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). It is marketed under the brand name Adempas and was developed by Bayer.

Mechanism of action is dual: riociguat directly stimulates sGC and also increases the sensitivity of sGC to endogenous nitric oxide. This leads to elevated cyclic guanosine monophosphate (cGMP) levels, resulting in relaxation of vascular smooth muscle, particularly in the pulmonary circulation, reduced pulmonary vascular resistance, and potential slowing of vascular remodeling. The net effect is improved exercise capacity and hemodynamics in eligible patients.

Indications include PAH in adults (typically WHO functional class II–III) and inoperable or persistent CTEPH after surgery. It is intended for use when other therapies are appropriate and is used as monotherapy or in combination with other PAH therapies, depending on clinician judgment and regulatory guidelines.

Administration and dosing are oral, taken three times daily with meals. The typical starting dose is 1 mg three times daily, with titration by 0.5 mg three times daily every two weeks to a maximum of 2.5 mg three times daily. Dosing may be adjusted for hypotension or hepatic impairment. Riociguat is contraindicated with nitrates and with phosphodiesterase-5 inhibitors due to the risk of significant hypotension. It is also contraindicated in pregnancy.

Common adverse events include headache, dizziness, hypotension, dyspepsia, nausea, diarrhea, and anemia. Pharmacokinetically, riociguat has a half-life of about seven hours, is metabolized mainly by CYP enzymes, and is absorbed more effectively with meals.