SOUTH SAN FRANCISCO, Calif. and MEMPHIS, Tenn., April 22 /PRNewswire/ -- Actelion Pharmaceuticals US, Inc., today announced that it has selected Accredo Health Group, Inc., a wholly-owned subsidiary of Medco Health Solutions, Inc., to serve as the sole specialty pharmacy provider of Epoprostenol for Injection, the only epoprostenol formulated to provide up to 24-hour stability at room temperature without the use of ice packs. This improved formulation of Epoprostenol for Injection is commercially available today in the United States for the treatment of primary pulmonary hypertension and pulmonary hypertension associated with scleroderma spectrum of disease in NYHA Class III and IV patients who do not respond adequately to conventional therapy.