Ganciclovir is a nucleoside analogue and antiviral agent used in therapy of cytomegalovirus infections. Valganciclovir is the valyl ester prodrug of ganciclovir which can be given orally. When given intravenously, ganciclovir can cause mild, transient and asymptomatic elevations in serum aminotransferase levels, but neither ganciclovir nor valganciclovir have been associated with clinically apparent liver injury.