In the last 20 years, many trials have been carried out to evaluate the benefits and risks of pulmonary arterial hypertension (PAH)-targeted therapies. Several studies and meta-analyses have shown these drugs improve symptoms, exercise capacity, and hemodynamic variables and prevent clinical deterioration and death in patients with PAH.1,2 In an observational study by Tan et al3 in a recent issue of CHEST (April 2015), the patients received variable dosages of different PAH medications. The data were compared with published cohorts, showing similar results. The authors’ conclusion was that, despite using low dosages of PAH medications, such therapeutic schemes were safe and cost-effective, allowing health agencies to potentially save money. However, some of the dosages used by Tan et al,3 such as tadalafil 10 or 20 mg/d, were less effective than 40 mg/d as shown in the Pulmonary Arterial Hypertension and Response to Tadalafil (PHIRST) randomized double-blind clinical trial.4 Other dosages, such as bosentan 31.25 mg bid or sildenafil 25 mg/d, have never undergone phase 3 trials. In these cases, we do not know if the therapy will cause benefit, cause harm, or have no effect and perhaps waste funds. Obviously, in real life some patients do not tolerate the recommended dosage, but we should attempt to reach it.