Ganciclovir is an analogue of acyclovir which is active against all herpes viruses including H.simplex,H.zoster,EBV, & CMV against which it is most active.It is activated intracellularly by virus spcific thymidine kinase& its triphosphate nucleotide preferentially inhibits viral DNA polymerase .This active metabolite attains much higher concentration inside CMV infected cells. I.V infusion of ganciclovir can prevent blindness in AIDS patients with CMV retinitis . Tripathi essentials of medical pharmacology 7th edition pg no 801.