Antivirals Flashcards
What are the three mechanisms of antivirals?
Inhibition of viral genome replication
Inhibit viral uncoating
Inhibition of viral release
What is the mechanism of acyclovir?
Phosphorylated via HZV or VZV thymidine kinase
What is the distribution of acyclovir?
Good CSF penetration for treatment of viral meningitis
How is acyclovir eliminated?
Renally
Requires dose reduction
What are the adverse effects of acyclovir?
Reversible nephrotoxicity
Crystalline nephropathy with high dose
CNS - HA, Hallucinations and Seizures
What is the mechanism of Valacyclovir?
PO, essentially completely converted to acyclovir
What are the symptoms and treatment of HSV encephalitis?
Fever, Focal neurologic symptoms
Treatment - IV acyclovir
What topical antiviral is used to treat oral herpes simplex?
Dcosanol (Abreva)
What topical antivirals are used to treat genital/perianal warts?
Imiquimod
Podofilox
What is podophyllin used for?
25% liquid administered in clinic directly to wart
What is used to treat CMV Retinitis?
Ganciclovir
What is the MOA of Ganciclovir?
Similar to acyclovir, but 10x more potent than acyclovir against CMV
What are the adverse effects of Ganciclovir?
CNS w/ Behavior changes and headache
N/V
Neutropenia and Thrombocytopenia
What is Valaganciclovir used to treat?
CMV retinitis
CMV prophylaxis
What is used to to treat HSV cold sores?
Penciclovir as topical cream
What is used to treat HSV and HZ?
Famciclovir
What is the mechanism of Penciclovir and Famciclovir?
Similar to that of acyclovir
What is the use of Cidofovir?
Reserved for CMV retinitis when other treatments fail
Administer with normal saline to decrease chances of nephrotoxicity
What is the MoA of Foscarnet (Foscavir)?
Competes for pyrophosphate in viral DNA polymerases
What are the ADRs of foscavir?
Nephrotoxic
Seizures, Anemia, Neutropenia
EKG changes - 1st degree AV Block
Hyper/Hypotension
What are the clinical uses for Foscavir?
Second line agent
CMV in AIDS patients
Acyclovir resistant Herpes Simplex in immunoscompromised ptns
What is the MoA of Amantadine and rimantadine?
Prevents virus from entering host cell
What does amantadine require that rimantadine does not?
Amantadine requires renal adjustment
Rimantadine does not
What are the ADRs for amantadine and rimantadine?
Confusion, Insomnia
More pronounced with amantadine
What is the clinical use of amantadine and rimantadine?
Treat and prevent Influenza A
Amantadine has a small roll in Parkinsons
What is the MoA of Osteltamivir and Zanamivir?
Inhibits neuroaminidase which is required for the release of the virus from infected cells
What are the ADRs of Osteltamivir?
PO causes GI side effects
What are the ADRs of Zanamivir?
Dry powder may cause wheezing and bronchospasm
Avoid COPD/Asthma patients
What are the clinical uses of osteltamivir and zanamivir?
Both Px and Tx Influenza types A and B
