ACYCLOVIR: Drug Interactions ACYCLOVIR PlUS AZT(Zidovudine) Increase antiviral activity in test tubes(inhibits DNA synthesis by HIV RT by the same 2-step mechanism) INTERFERON-C Increase antiviral activity in test tubes PROBECENID May increase Acyclovir levels in blood and decrease Acyclovir clearanceACYCLOVIR: Drug Interactions ACYCLOVIR Plus... AZT (Zidovudine) Increase antiviral activity in test tubes (inhibits DNA synthesis by HIV RT by the same 2-step mechanism). INTERFERON-a Increase antiviral activity in test tubes. PROBECENID May increase Acyclovir levels in blood and decrease Acyclovir clearance. ! ! !