Inhalation profiles to support use of dry powder inhalers (DPIs) for drug delivery in patients with pulmonary arterial hypertension (PAH) have not been reported. We aimed to evaluate the inspiratory flow pattern associated with low and medium flow resistance DPI devices (RS01-L, RS01-M, respectively) in patients with PAH. This single-center study enrolled patients with PAH associated with connective tissue disease (aPAH,n=10) and idiopathic PAH (iPAH,n=10) to measure the following inhalation parameters: inspiratory effort (kPa), peak inspiratory flow rate (L/min), inhaled volume (L), and flow increase rate (L/s2) using the two devices. We identified a trend toward higher mPAP in the iPAH group (50±13mmHg vs. 40±11mmHg in aPAH;p=0.077). On average, peak inspiratory flow rate was higher with RS01-L vs. RS01-M (84±19.7 L/min vs. 70.4±13.2 L/min; p=0.015). In the overall group, no differences between RS01-L and RS01-M were observed for inhaled volume, inspiratory effort, or flow increase rate. Inhaled volume with RS01-L was higher in aPAH vs iPAH patients: 1.6±0.4L vs. 1.3±0.2L;p=0.042. For the RS01-L, inhaled volume correlated with forced expiratory volume in one second (r=0.460, p=0.030) and forced vital capacity (r=0.50,p=0.015). In patients with aPAH using RS01-L, both inspiratory effort and flow increase rate were highly correlated with pulmonary vascular compliance (r=0.903,p=0.0001 and r=0.906,p=0.001; respectively); while with RS01-M, inspiratory effort was highly correlated with pulmonary vascular compliance (r=0.81,p=0.001). Our data suggest that the use of RS01-L and RS01-M DPI devices allowed adequate inspiratory flow in PAH patients. The correlation between flow increase rate and pulmonary vascular compliance in aPAH deserves further investigation.