Activity of Penciclovir in Combination with Azido-Thymidine,Ganciclovir,Acyclovir,Foscarnet and Human Interferons against Herpes Simplex Virus Replication in Cell Culture

Abstract

Combinations of penciclovir (PCV) with other antiviral agents (acyclovir, ACV; ganciclovir, GCV; foscarnet, PFA; azido-thymidine, AZT) or with human interferons (HulFN-α,β,γ) were tested for inhibitory activity against herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2) in cell culture. The antiviral interactions observed between combinations of PCV with ACV or GCV were purely additive. Combinations of PCV with HulFNs demonstrated highly synergistic anti-herpesvirus activity; some synergy was also detected between PCV and PFA against HSV-1. High concentrations of AZT inhibited the antiviral activity of PCV; this antagonism was competitive. In more detailed studies it was demonstrated that high concentrations of AZT also inhibited the antiviral activity of ACV, and that ACV was more sensitive to this antagonism than PCV. It was concluded that the antagonism was unlikely to have clinical significance.