Valacyclovir

In pharmacology and virology, valacyclovir (Valtrex)is "a prodrug of acyclovir; 53% of oral dose excreted as acyclovir in the urine; a 200-400% improvement on acyclovir; used in the management of HSV and VZV infections and the prophylaxis of HCMV infections; RN given  refers to the monohydrochloride L-valine isomer."