Drug-Drug:
- ↑risk of hypotension with concurrent use of nitrates, nitric oxide donors (including amyl nitrate), specific PDE-5 inhibitors including sildenafil, tadalafil, or vardenafil, and non-specific PDE-5 inhibitors such as dipyridamole or theophylline; concurrent use contraindicated; discontinue sildenafil
24 hr prior to starting riociguat; discontinue tadalafil48 hr prior to starting riociguat; discontinue riociguat 24 hr before starting PDE-5 inhibitor. - Strong CYP and P-gp/BCRP inhibitors including azole antifungals (ketoconazole and itraconazole) and protease inhibitors (ritonavir) ↑ blood levels and the risk of adverse reactions including hypotension (consider ↓ initial dose).
- Strong CYP3A inducers including carbamazepine, phenobarbital, phenytoin and rifampin↓ blood levels and may ↓ effectiveness.
- Concurrent use of antihypertensives including diuretics may ↑ risk of hypotension.
- Antacids↓ absorption (separate doses by at least 1 hr)
- Cigarette smoking ↓blood levels and effectiveness, ↑ dose may be necessary and dose readjustment required after smoking cessation.
Drug-Natural Products:
- St. John's wort ↓blood levels and may ↓ effectiveness.
