Used to treat Gaucher disease type 1, a genetic disorder caused by deficiency of the enzyme glucocerebrosidase. It works as a substrate reduction therapy by inhibiting glucosylceramide synthase, reducing the buildup of glucosylceramide in cells. This helps alleviate symptoms such as enlarged liver and spleen, low hemoglobin, and reduced platelet count. Taken orally, it offers a first-line treatment option for adults with specific CYP2D6 metabolizer statuses, providing an alternative to enzyme replacement therapy.