Prophylaxis against influenze A:

Development of resistance to acyclovir (Zovirax) in varicella-zoster virus:

First-pass metabolism of this drug results in the active form, penciclovir (Denavir):

Monophosphorylation of this antiviral drug is catalyzed by virus-specified protein kinase phophotransferase in CMV-infected cells and by viral thymidine kinase in HSV-infected cells.

Nephrotoxicity, the major dose-limiting toxicity associated with i.v. use of this drug can be prevented by probenecid (Benemid) (a blocker of tubular secretion)

Mainly eliminated by renal mechanisms as the hypoxanthine metabolite, this antiviral agent is effective for treating acute keratoconjunctivitis (ointment) and HSV encephalitis (i.v.)

Inhibition of viral replication by: (1) Competitive inhibition of HIV reverse transcriptase and (2) by chain termination.

Drug-drug interactions:

Effective in prevention of influenza A viral infection in high risk individuals:

HIV protease inhibitor