Antiviral drugs Flashcards
antiviral treatments for herpesviruses are indicated for which members of the herpresvirus family?
VZV
HSV-1
HSV-2
CMV
what type of drug is acyclovir?
nucleoside analogue
what is the MOA of acyclovir?
competitive inhibitor of the viral genome DNA pol
chain termination upon incorporation into viral DNA
what is required for acyclovir MOA?
phosphorylation of viral thymidine kinase enzyme
what is the bioavailability of acyclovir?
low
15-20%
what are the indications of acyclovir?
oral - genital herpes, varicella zoster
IV - neonate infections, severe disseminated mucocutaneous disease, HSV encephalitis, VZV in compromised patients
what are the adverse effects of acyclovir?
nausea, headache, diarrhea
crystalline nephrotoxicity
acyclovir use is cautioned in what condition?
concomitant adminstration of nephrotoxic agents
what is valacyclovir?
prodrug of acyclovir
what is the advantage of valacyclovir?
3-5x greater oral bioavailability
what are the therapeutic indications for valacylcovir?
primary and recurrent genital herpes
varicella in older children and adults
zoster
orolabial herpes
what type of drug is foscarnet?
analogue of pyrophosphate
what is the MOA of foscarnet?
occupies site where pyrophosphate normally resides and blocks pyrophosphate release - blocks catalytic cycle
does foscarnet require prior phosphorylation by thymidine kinase?
no
what is the route of administration for foscarnet?
IV only
what are the indications for foscarnet?
HSV and VZV resistance (to acyclovir)
CMV retinitis, CMV colitis, CMV esophagitis
what are the adverse effects of foscarnet?
renal impairment
blood chem - changes Ca, P, Mg levels
foscarnet use is cautioned in what condition?
concurrent administration of nephrotoxic drugs
what type of drug is ganciclovir?
acyclic guanosine analogue
what is the MOA of ganciclovir?
competitive inhibitor viral DNA pol
chain termination upon incorporation into viral DNA
does ganciclovir require prior phosphorylation by viral kinase?
yes
what are the therapeutic indications for ganciclovir?
CMV retinitis / colitis / pneumonitis / esophagitis