Pulmonary arterial hypertension (PAH) is a devastating disease that leads to right heart failure and premature death. Historically, we are restricted by limited options for drug treatment. Over the past decade, with advances in our understanding of pathophysiological and molecular mechanisms, many new therapeutic strategies (synthetic prostacyclin and prostacyclin analogues, endothelin receptor antagonists and sildenafil) have been developed for the treatment of PAH, and the clinical efficacy has been tested in many randomized-controlled trials (RCTs). In this overview, we review the evidence for the use of historical and new treatments that arises from the Cochrane Collaboration of Systematic Reviews and from recent RCTs.