Antiviral Medications Flashcards
Acyclovir: MOA
- Phosphorylated by THYMIDINE KINASE
- Inhibits viral DNA polymerase
- Chain termination
CSF penetration by Acyclovir
Good
Placenta/Umbilical cord penetration (acyclovir)
Good
What formulation(s) is Acyclovir available in
- Oral
- IV
- Topical
2 side effects mainly associated with IV Acyclovir treatment
- Phlebitis
- Renal Toxicity
Common side effect associated with virtually ALL antiviral medications that are taken orally or IV
CNS (headache, hallucinations, seizure)
Main use of acyclovir (3)
- Herpes Simplex
- Herpes Zoster
- Viral Encephalitis (IV formulation)
What is acyclovir in-effective in treating
Cytomegalovirus
What drug is the “prodrug” of acyclovir
Valacyclovir
Valacyclovir: MOA
Same as acyclovir, it must go through first pass metabolism however, to become active
What formulation (s) is valacyclovir available in
Oral only
2 reasons why valacyclovir is used instead of acyclovir
- Less frequent dosing
2. Good option if IV access is unavailable or refused by patient
Main use of valacyclovir (2)
- Herpes Simplex
- Herpes Zoster
Ganciclovir: MOA
Same as acyclovir
Main use of Ganciclovir (2)
- CMV infections
- Epstein-Barr
T/F Ganciclovir can be used to treat Herpes Simplex and Herpes Zoster
True, works very well. It’s main use however is with CMV and Epstein-Barr infections
Main adverse effect of ganciclovir useage
Bone marrow suppression (neutropenia-main) (thrombocytopenia)
What drug is the “prodrug” of ganciclovir
Valganciclovir
Main use of Valganciclovir
CMV (retinitis and prophylaxis)
Penciclovir: MOA
Same as acyclovir
What formulation (s) is penciclovir available in
Topical cream only (1%)
Main use of penciclovir (1)
-Herpes Simplex (cold sores)
What is the “prodrug” of penciclovir
Famciclovir
T/F Famciclovir is only available topically
False, oral versions are available
Main use of famciclovir (2)
- Herpes Simplex
- Herpes Zoster
Cidofovir: MOA
-Interacts with DNA polymerase
T/F cidofovir requires thymidine kinase
False
Main adverse reaction associated with cidofovir useage
Nephrotoxicity!!!
What must cidofovir be administered with due to its major side effect of nephrotoxicity (2)
- Saline
2. Probenecid
How often is cidofovir administered
Once weekly
Main use of cidofovir (1)
-CMV retinitis in AIDS patients
What drug should be tried first before cidofovir or foscarnet should be used
Ganciclovir
Foscarnet: MOA
-Competes for pyrophosphate site on DNA polymerase
T/F foscarnet requires thymidine kinase
False
Main adverse reaction associated with foscarnet usage
Nephrotoxicity!!!
Main use of foscarnet (2)
- CMV retinitis in AIDS patients
- Acyclovir resistant Herpes Simplex
Interferon: MOA
Unknown
What is an interferon
- Produced by cells in the body that have been infected by a virus
- IMMUNE SYSTEM IN A BOTTLE
Adverse reactions to using interferons
Similar to actually obtaining a viral infection, influenza-like reaction
2 types of interferons
Type I and Type II
Main use of interferons
Treatment for Hep. B and C infections
Type I interferons
alpha: Hep B and C
beta: Multiple sclerosis
Type II interferons
gamma: Not commercially available
Lamivudine: MOA
-Inhibits reverse transcriptase
What drug is lamivudine generally combined with
Interferons
Main adverse reaction with lamivudine use
BLACK BOX WARNING
- Lactic acidosis
- Severe Hepatomegaly
Main use of lamivudine (2)
- Hep B virus
- HIV
Ribavirin: MOA
Unknown
Adverse effect with ribavirin use (1)
Anemia
Main use of ribavirin (2)
- RSV infections (bronchitis/pneumonia)
- Hep C
What age group is ribavirin commonly used in
Children
Imiquimod: MOA
Induces local interferon and TNF-alpha release
What disease is imiquimod used to treat
Genital warts
Amantadine/Rimantidine: MOA
Prevents virus from entering susceptible cells
Which drug (amantadine/rimantidine) has worse CNS effects
Amantadine
Which drug (amantadine/rimantidine) requires renal adjustment
Amantadine
Main use of amantadine/rimantidine (2)
- Prophylaxis of Influenza A
- Treatment of Influenza A
To treat influenza A, when does amantadine/rimantidine therapy need to be started
Within first 48 hours of symptoms
What other disease has amantadine been shown to treat, however it is not routinely used
Parkinsonism
Osteltamivir/Zanamivir: MOA
-Inhibits influenza virus neuroaminidase
Neuroaminidase is required for
Release of the virus from infected cells
Osteltamivir adverse reaction (1)
GI discomfort (nausea, vomiting, abdomen pain)
Zanamivir adverse reaction (2)
- Wheezing
- Bronchospasm
What does zanamivir have respiratory system associated reaction?
It is an oral inhalation of dry powder
Use of zanamivir is discouraged in what 2 diseases?
- COPD
- Asthma
Osteltamivir/Zanamivir is used to treat what
Influenza A and B
How helpful are osteltamivir/zanamivir?
Not very, they reduce Flu symptoms 1 day
