Aviptadil, a vasoactive intestinal polypeptide, is a vasodilator and lowers blood pressure if administered intravenously. In 2007, the orphan designation was granted by the European Commission for aviptadil for the treatment of sarcoidosis, a disease of unknown cause that affects many organs and tissues, most commonly the lungs. Sarcoidosis is characterized by specific microscopic lesions called granulomas. Aviptadil is able to influence the immune system that decreases the inflammatory processes seen in sarcoidosis by acting on the white blood cells (lymphocytes and monocytes) involved in the formation of the granulomas. In combination with phentolamine, the drug is used to treat erectile dysfunction. In addition, aviptadil has been studied in phase II clinical trials for patients with respiratory distress syndrome.