Tadalafil and opsumit?

Short answer: Yes, tadalafil (a PDE-5 inhibitor) and Opsumit (macitentan, an ERA) can be used together for pulmonary arterial hypertension under a doctor’s supervision. They are often used in combination therapy.

Key points to know
- Why they’re used together: They work by different mechanisms to improve blood flow in the lungs and can have complementary benefits.
- Safety and monitoring:
- Blood pressure: Both can cause low blood pressure or dizziness. Monitor for lightheadedness, especially when standing up.
- Liver and blood counts: Macitentan can affect liver enzymes and can cause anemia. Regular LFTs and CBCs are usually recommended.
- Pregnancy: Macitentan is teratogenic (pregnancy category X). Women of childbearing potential should use effective contraception. Tadalafil’s pregnancy risk is lower (label: category B), but discuss plans with your clinician.
- Nitrates: Do not use organic nitrates (e.g., nitroglycerin) with tadalafil due to risk of dangerous low blood pressure.
- Drug interactions:
- Both drugs are metabolized by CYP3A4. Strong inhibitors or inducers of CYP3A4 can alter levels of either drug. If you’re taking a strong CYP3A4 inhibitor (e.g., ketoconazole) or inducer (e.g., rifampin), your doctor may adjust doses or choose a different regimen.
- Other blood pressure–lowering medicines or alpha-blockers can increase the risk of hypotension.
- Dosing: The specific doses should be as prescribed by your doctor. Typical PAH regimens are macitentan once daily and tadalafil once daily (tadalafil is often 40 mg daily for PAH in the US), but your dosing may differ.

If you have a specific scenario (other meds, liver issues, nitrates use, or pregnancy considerations), tell me and I can tailor the info. Always consult your prescribing clinician before making any changes.