Antiviral Agents Flashcards
Amantadine Rimantadine
Mechanism of Action ?
inhibit viral uncoating by block of viral M2 proton channel
Amantadine and Rimantidine
Pharmacokinetics?
good po, accumulates in lungs
renal [A] or hepatic [R]
elimination
Amantadine Rimantadine
Adverse Reactions?
GI upset insomnia, confusion, headache (decrease CNS effects with rimantadine)
Oseltamivir, Zanamivir, Peramivir
Mechanism of Action?
inhibit viral neuraminidase to decrease viral budding ( decrease infectivity)
Oseltamivir, Zanamivir, Peramivir
Pharmacokinetics?
oseltamivir (orally as prodrug)
zanamivir (inhalation)
peramivir (intravenous)
all renally excreted
Oseltamivir, Zanamivir, Peramivir
Adverse Reaction?
nausea/vomiting (oseltamivir)
bronchospasm (zanamivir)
Acyclovir[155] , Valacyclovir [113], Penciclovir, [Famciclovir]
Mechanism of Action?
phosphorylated by viral thymidine kinase inhibits viral DNA polymerase plus chain termination
Acyclovir[155] , Valacyclovir [113], Penciclovir, [Famciclovir] Pharmacokinetics?
VAL / FAM: 80%(prodrugs),
P: topical only]
renal excretion
Acyclovir[155] , Valacyclovir [113], Penciclovir, [Famciclovir]
Adverse Reaction?
minor toxicities (headache, n/v) higher levels with valacyclovir may increase risk of CNS / renal side effects
Docosanol (OTC)
Mechanism of Action?
inhibits fusion between plasma membrane and HSV envelope
Docosanol (OTC)
Pharmacokinetics?
topically applied 5 X daily
Docosanol (OTC)
Adverse Reaction?
well tolerated
Cidofovir
Mechanism of Action?
nucleotide analog, phosphory lated to active form by host kinases, inhibits viral DNA poly
Cidofovir
Pharmacokinetics?
long intracellular t1/2 (17-35h) given IV weekly / biweekly
Cidofovir
Adverse Reaction?
nephrotoxicity (decreased
by probenecid use) rash in HIV patients
Foscarnet
Mechanism of Action?
pyrophosphate analog, (no activation step), inhibits viral/DNA/RNA polymerase and RT
Foscarnet
Pharmacokinetics?
poor oral bioavailability
requires continuous infusion
Foscarnet
Adverse Reaction?
renal impairment, severe n/v electrolyte imbalance (esp. hypocalcemia)
Ribavirin
Mechanism of Action?
triphosphorylated to active form inhibits IMP dehydrogenase,
viral RNA-dep RNA polymerase
Ribavirin
Pharmacokinetics?
aerosol administration
well-absorbed orally
long intracellular t1/2
Ribavirin
Adverse Reaction?
low aerosol toxicity, but teratogen,
systemic toxicity includes anemia,
bone marrow depression
Amphotericin
Mechanism of Action?
binds to ergosterol, forming pores in membranes with loss of vital intracellular constituents
Amphotericin
Pharmacokinetics?
IV or tropical only
Slow excretion by kidney plus hepato-biliary (t1/2 15d)
Amphotericin
Adverse Reaction?
acute: fever/chills on infusion
nephrotoxicity (80%), anemia
Nystatin
Mechanism of Action?
same as amphotericin
Nystatin
Pharmacokinetics?
topical only
not absorbed orally
Nystatin
Adverse Reaction?
well tolerated given topically
mild GI upset (if swallowed)