Valganciclovir is primarily used in the prevention and treatment of cytomegalovirus (CMV) infections, particularly in immunocompromised patients such as those who have undergone organ transplants or are living with HIV/AIDS. It is effective in reducing the risk of CMV disease in kidney, heart, and kidney-pancreas transplant recipients. Additionally, it is used to treat CMV retinitis in AIDS patients, helping to prevent blindness. Valganciclovir is also administered to manage congenital CMV infections in newborns, aiming to reduce the severity of associated complications. Its oral bioavailability makes it a convenient alternative to intravenous therapies, improving patient compliance and quality of life.