Abstract
Pulmonary arterial hypertension (PAH) is a condition associated with substantial morbidity and mortality. Over the last 25 years there has been a significant evolution in the therapies to treat PAH. These therapies are effective for patients with group I PAH and group IV PH [chronic thromboembolic pulmonary hypertension (CTEPH)]. PAH is characterized by an imbalance of nitric oxide, prostacyclin and endothelin levels, and current pharmacotherapy involves these three pathways. Earlier clinical trials involving PAH-specific therapies evaluated improvements in 6-minute walk time as a primary improvement whereas contemporary trials have been larger and focused on morbidity and mortality reductions. While there may be a role for monotherapy in disease management, most patients should be considered for dual or triple therapy.