In my previous post i mention im going back on famvir after being on valtrex now for 7 months and prior to that 12 months on famvir. My personal experience with the 2 drugs is that i feel famvir is more effective, while googling/researching i came accross an interesting article , just remember famvir converts to penciclovir in the body :- It is the oral form of penciclovir, a nucleoside analogue, which has a similar antiviral spectrum to acyclovir for the herpesviruses with approximately similar potency, although penciclovir generates higher intracellular triphosphate concentrations. In tissue culture experiments, penciclovir triphosphate was reported to have a prolonged intracellular half-life; 1020 h in herpes simplex virus (HSV)-1- and HSV-2-infected cells compared with 0.71 h in HSV-1- and HSV-2-infected cells for acyclovir (Crumpacker et al., 1996). I wonder if its prolonged intracellular half life is why I find it more effective. Even though it doesnt refer to ebv, Im sure it would also have an increased effect. Time will tell as i have just finished my first day back on famvir. cheers!!!