Adcirca is a medicine used in the treatment of pulmonary hypertension. It is also used to improve the exercise capacity in individuals. The active pharmaceutical ingredient of the medicine is tadalafil, which functions in the body as a PDE5 inhibitor. This means the drug causes blood vessel dilation which, in turn, helps to resolve pressure in the lungs. However, this dilation occurs throughout the entire body, meaning hypotension remains a real risk. This is why the drug should be avoided in patients who have cardiovascular disease and who are already taking antihypertensive medication.