Treprostinil (marketed under the trade names Remodulin for infusion) is a vasodilator that is used for the treatment of pulmonary arterial hypertension. Pulmonary arterial hypertension (PAH) is a disease in which blood pressure is abnormally high in the arteries between the heart and lungs. PAH is characterized by symptoms of shortness of breath during physical exertion. The condition can ultimately lead to heart failure. Treprostinil is a potent oral antiplatelet agent. The major pharmacologic actions of treprostinil are direct vasodilation of pulmonary and systemic arterial vascular beds and inhibition of platelet aggregation. In animals, the vasodilatory effects reduce right and left ventricular afterload and increase cardiac output and stroke volume. Other studies have shown that treprostinil causes a dose-related negative inotropic and lusitropic effect. No major effects on cardiac conduction have been observed. Treprostinil had high affinity for the Prostaglandin D2 receptor (DP1), Prostaglandin E2 receptor EP2 subtype (EP2) and Prostaglandin D2 receptor (IP) receptors (Ki 4.4, 3.6 and 32 nM, respectively), low affinity for EP1 and EP4 receptors and even lower affinity for EP3, Prostaglandin F (FP) and thromboxane (TP) receptors. Treprostinil has demonstrated a unique effect on PPAR gamma, a transcription factor important in vascular pathogenesis as a mediator of proliferation, inflammation and apoptosis. Through a complementary, yet cyclic AMP-independent pathway, treprostinil activates PPARs, another mechanism that contributes to the anti-growth benefits of the prostacyclin class.