Eltrombopag is used to treat low blood platelet counts (thrombocytopenia) in patients with chronic immune thrombocytopenic purpura (ITP) who have not responded well to other treatments. It works by stimulating the bone marrow to produce more platelets, reducing the risk of bleeding and bruising. It is also used in patients with chronic hepatitis C to help maintain platelet levels during antiviral therapy, allowing them to continue treatment without dose reductions. Additionally, eltrombopag is used in certain cases of severe aplastic anemia when other treatments are not effective, helping to improve blood cell production.