Anti-Viral Flashcards
Herpesvirus
DNA virus - encode on DNA polymerase (target)
Lytic phase - only time to treat
Drugs to treat Herpesvirus
Acyclovir Valacyclovir Foscarnet Ganciclovir Valganciclovir Trifluridine
MOA Acyclovir
nucleoside analog - requires phosphorylation by viral thymidine kinase
Competitive inhibitor of viral DNA Polymerase - chain termination
Oral vs IV Acyclovir
Oral - genital herpes, VZV
IV - severe/disseminated, neonatal, HSV encephalitis, VZV in IC
RES Acyclovir
mutation of thymidine kinase
Cross-resistance with other anti-virals of same mechanism
AE Acyclovir
mild; come nephrotoxicity and neurotoxicity
Valacyclovir
prodrug of Acyclovir; metabolized to Acyclovir
3-5x greater bioavailability
Indicated: primary/recurrent genital herpes, varicella in older children/adults, Zoster, orolabial herpes
MOA Foscarnet
pyrophosphate analog; blocks pyrophosphate release which blocks DNA polymerase
Does not require phosphorylation
Only IV administration
Indications for Foscarnet
HSV/VZV resistant to Acyclovir
Also: CMV, retinitis, colitis, esophagitis
AE Foscarnet
renal impairment - avoid nephrotoxic drugs
Blood ion changes
MOA Ganciclovir
requires phosphorylation by CMV UL97 - competitive inhibitor for DNA polymerase
IV administration; also oral, intraocular
RES Ganciclovir
mutation of CMV UL97
Cross-resistance with drugs of same mechanism
Indications for Ganciclovir
CMV retinitis, colitis, pneumonitis, esophagitis
AE Ganciclovir
Myelosuppression, BM/CNS toxicity, phlebitis, rash
Valganciclovir
prodrug of Ganciclovir
higher bioavailability
Indicated: CMV retinits, prevention of CMV disease in pts with heart, kidney pancreas transplant