Abstract
Prostacyclin pathway agents are a critical treatment for patients with pulmonary arterial hypertension. Seven prostacyclin pathway agents are available, including agents administered by parenteral infusion, by inhalation, and orally. Pulmonary arterial hypertension patients are now transitioned from one prostacyclin pathway agent to another with increasing frequency. Such transitions require careful downtitration and uptitration to avoid decompensation from rapid withdrawal and to achieve a patient's optimal dose based on efficacy and tolerability. Clinical guidance is especially lacking for transitions involving the newer, oral prostacyclin pathway agents; specifically, selexipag and oral treprostinil. We present three case reports of patients with pulmonary arterial hypertension who underwent one or more transition between parenteral and oral prostacyclin pathway agents, including some transitions that were successful and some that were not. These cases illustrate key considerations, such as titration protocols, patient selection, side effect management, and pharmacokinetics.