Sildenafil for pulmonary arterial hypertension: when blue turns into white

Pulmonary arterial hypertension is a life-threatening, rare disease characterised by vasoconstriction and vascular remodelling of pulmonary artery vessels. Pulmonary arterial hypertension can occur without an obvious cause or can be secondary. Until several years ago, therapeutic approaches were represented mainly by 'conventional therapy' (anticoagulants, calcium channel blockers, diuretics and digoxin, and oxygen therapy). But recently 'specific therapies' (i.e., therapies targeting specific pathogenic pathways) have become available; these are therapies represented by prostacyclin and its derivatives, endothelin receptor antagonists or phosphodiesterase-5 inhibitors. Sildenafil citrate is a phosphodiesterase-5 inhibitor and is the second oral pharmacological agent recently approved for the treatment of pulmonary arterial hypertension. Sildenafil has demonstrated short- and long-term clinical efficacy in the treatment of various forms of pulmonary arterial hypertension, either alone or in combination with other agents, but its safety profile needs further assessment.