aciclovir UK /eɪˈsaɪ.klə(ʊ)ˌvɪə/US /eɪˈsaɪ.kloʊˌvɪɹ/ noun1 •A cyclic synthetic nucleoside C₈H₁₁N₅O₃ used as an antiviral drug (trademarks Avirax, Zovirax) chiefly in the treatment of chicken pox, shingles, the genital form of herpes simplex, and AIDS.In cells infected with the herpes virus, acyclovir is converted to a metabolic blocking agent, thereby largely overcoming the old and plaguing problem of toxicity to the host. — 1997
