A 5-phosphodiesterase inhibitor with uses similar to sildenafil, used in the treatment of pulmonary hypertension, erectile dysfunction in men, Raynaud's syndrome and in other treatments due to its vasodilatory effect on smooth muscle. Since the last update, we have not found published data on its excretion in breast milk. Its high percentage of protein binding makes it unlikely that it will be transferred to milk in significant amounts, as in fact has been seen in another drug from the same therapeutic group, sildenafil. Until there is more published data on this drug in relation to breastfeeding, safer known alternatives may be preferable, especially during the neonatal period and in case of prematurity.