Sildenafil therapy for interferon-β-1a-induced pulmonary arterial hypertension: a case report.

Interferon (IFN) therapy is nowadays widely used in clinical practice. In the literature, there are very few reports of the association between IFN therapy and pulmonary arterial hypertension (PAH), and current guidelines do not mention IFNs as a risk factor for PAH. We describe a patient with multiple sclerosis who developed severe PAH after treatment with IFN-β-1a and the clinical response to sildenafil. Furthermore, we stress the need to further investigate the link between IFNs and PAH.