Ganciclovir is available in either an oral or an intravenous formulation. The obvious advantages of the oral formulation are somewhat offset by the fact that its bioavailability is only 8 to 10%. The product has been reformulated with the addition of an L-valyl ester; the resulting compound, valganciclovir (Valcyte™) is metabolized to ganciclovir and has a 3 to 7 fold increase in bioavailability and is able to maintain serum concentrations equivalent to the intravenous formulation. This provides a convenient method for obtaining therapeutic concentrations of ganciclovir for extended periods of time without the need for in-dwelling intravenous lines.