CMV nucleoside analogues are used to treat and prevent cytomegalovirus (CMV) infections, especially in certain groups of people with weakened immune systems. They also have other uses, such as treating acute herpetic keratitis. These medications work by inhibiting the replication of the CMV virus. CMV nucleoside analogues come in different forms, including oral pills, liquids, and injectable solutions. Examples include valganciclovir (Valcyte), ganciclovir (Zirgan), and letermovir (Prevymis).