Exogenous intravenous (IV) adenosine and epoprostenol are effective vasodilator agents, causing a substantial reduction in pulmonary vascular resistance in patients affected by idiopathic pulmonary arteriolar hypertension (PAH). Their action, in patients with PAH associated with other pathological conditions, is not well defined. In the present paper the authors retrospectively analyzed the acute hemodynamic effects of intravenous adenosine and epoprostenol in 30 consecutive patients (mean age: 58 ± 15 years; 21 females, and 9 males) affected by PAH associated with other pathological conditions, as determined by changes from baseline in systemic and pulmonary hemodynamic parameters. Acute IV administration of adenosine decreased pulmonary vascular resistance index (PVRI) by 3 Wood U/m2 (- 20%) compared to baseline (p = 0.02). We noted a slight, not significant, decrease in mean pulmonary artery pressure (mPAP) of 4 mmHg. Cardiac index (CI) increased by 0.5 L/min/m2 (15% increase respect to baseline; p = 0.03). The heart rate and mean systemic blood pressure (BP) did not change significantly. Acute IV administration of epoprostenol decreased PVRI by 6 mmHg (- 40%) respect to baseline (p < 0.0001). CI increased by 1.4 L/min/m2 (p < 0.0001); while mPAP decreased by 5 mmHg (nearly 10%) (p = 0.04). This decrease of mPAP was accompanied by a mean BP decrease of 11 mmHg compared to baseline (p = 0.003). Our results indicates that, in patients with PAH associated with other pathological conditions, adenosine is predominantly a positive inotropic agent; and epoprostenol a potent vasodilator of both pulmonary and systemic vessels, and a strong positive inotropic agent.