Sildenafil is useful in pulmonary hypertension. But it has to be given thrice daily. Tadalafil is also a phosphodiesterase 5 inhibitor and it can be given once daily.

This trial meant to find whether tadalafil would be beneficial in pulmonary hypertension. It found that tadalafil reduces pulmonary artery pressure and pulmonary vascular resistance. Also, there is an increase in exercise tolerance. It also decreased the chance of clinical worsening. But there was no decrease in mortality or in subjective dyspnoea scores.

Even in patients on bosentan, these beneficial effects of tadalafil were seen, though to a lesser degree.

The dose of tadalafil used in the study was 40 mg daily.

This trial formed the basis of FDA approval of tadalafil 40 mg daily for pulmonary hypertension.