Q: What is the advantage of adding Sildenafil with inhaled NO in treatment of pulmonary hypertension?

Answer: Sildenafil not only decreases pulmonary pressures but also prevents rebound pulmonary vasoconstriction on withdrawal of inhaled NO.

Mehta S. Sildenafil for pulmonary arterial hypertension: exciting, but protection required. Chest. 2003 Apr; 123(4): 989-92.