Used primarily in the treatment of cytomegalovirus (CMV) infections, especially in immunocompromised patients such as those with AIDS or who have undergone organ or bone marrow transplantation. It is effective in managing CMV retinitis, helping to prevent vision loss by slowing the progression of the disease. The sodium salt form improves solubility, making it suitable for intravenous administration. It may also be used off-label in the prevention of CMV disease in high-risk patients. Due to its antiviral activity, it plays a critical role in reducing CMV-related complications in vulnerable populations.