Antiviral Drugs Flashcards
What are two types of virucidal treatments
- Detergents
2. cryotherapy
What is an immunomodulatory treatment?
alpha interferon
What are the four types of antivirals used ?
- nucleoside analogs
- nonnucleosides
- protease inhibitors
- entry inhibitors
Name a drug that affects viral entry and what disease it is used to treat
-Enfuvirtide - HIV
Nucleic acid synthesis inhibitors are primarily used to treat which two diseases?
Herpes virus and HIV
In treating HIV, what specifically is targeted , in concerining the assembly and release step ?
-Protease inhibitors
Influenza virus is treatable with zanamivir and oseltamivir, which both target the same step of virus replication - what is their target?
Neuramindase - cleaves sialic acid and releases virions from cell surface
What antiviral is used to affect the host’s intrinsic immunity and what viruses does it target?
- peg-interferon
- HCV, HBV
what are two “broad spectrum” treatments for DNA viruses?
foscarnet=foscavir
cidfovir=vistide
how does foscarnet/foscavir work? (to treat DNA viruses)
inhibit DNA polymerase
what type of virus is foscarnet/foscavir effective against? (to treat DNA viruses)
all herpesvirus
what are two negatives of using foscarnet/foscavir and cidofovir/vistide? (to treat DNA viruses)
can only be administered via IV
toxic to kidneys
what viruses are cidofovir/vistide active against?
herpesvirus
adenovirus
papillomavirus
pox virus
what are the current drug options for hep B?
Peglyated interferon alpha
Entecavir=baraclude
Tenoforvir disoproxil fumarate=viread
who should be treated for Hep B?
People with chronic active HBV disease
People co infected with HCV and/or HIV
People with progressing to cirrhosis, liver failure or hepatocellular carcinoma
what is the mechanism of action for the drugs treating influenza virus?
both are sialic acid analogs that inhibit viral neuraminidase causing the virion to stay attached to the cell and not be able to infect other cells
who should be treated for the influenza?
severely ill people children younger than 2 adults over 65 pregnant women immunosuppressed people anyone suspected to have influenza
list characteristics about Ribavirin
“broad spectrum” for RNA viruses
approved against HCV and RSV
can be given orally, IV or aerosol
what is the current treatment for hep C virus?
combination peg-interferon-alpha with ribavirin
what is the treatment for hep C with peg-interferon alpha considered difficult and complicated?
can cause flu like symptoms, anemia, neutropenia, rashes, hair loss, depression…
people want to stop taking them
AZT (old HIV treatment) is a nucleoside analog of..?
thymidine
cidofovir/vistide (treatment for DNA viruses) is a nucleoside analog of…?
cytosine
what are the 5 anti HIV drug classes?
- entry inhibitor
- nucleoside/tide RT inhibitor
- non nucleosdie/tide RT inhibitor
- integrase inhibitor
- protease inhibitor
what is cobicisat? (component of the new HIV treatment that can be taken in 1 pill)
it is liver enzyme enhancer
it boosts the other components in the treatment by preventing their break down in the liver
Describe the specificity of antivirals?
Most only target functions of one virus
Are most antivirals reversible or irreversible?
Reversible - competitive inhibitors
What does it mean that a virus rebounds after viral therapy?
Virus replication can resume when drug is cleared, and so treatment may need to be lifelong
Does resistance to an antiviral develop after treatment with the drug?
No - often exists before drug treatment
What are four factors favoring the emergence of resistance strains?
- high rate of replication
- high mutation rate (RNA»DNA)
- high selective drug pressure - long term treatments
- immunosuppressed can’t clear viruses
What are three ways we can counter resistance to antivirals?
- alleviate immunosuppression in a treated person
- combine drugs with different targets - need them to synergize
- Target host functions
What two infections, is the standard of care combining multiple synergistic treatments?
HCV and HIV
In order to treat zoster with an antiviral, what is the protocol?
Treatment only works within 3 days of appearance of rash
Acyclovir is a nucleoside analog of _____
Guanosine
What is the effectivity of acyclovir?
HSV1=HSV2»>VZV
What is the trade name of acyclovir?
zovirax
What are some names of derivatives of acyclovir?
Valtrex, denavir, famvir
What is acyclovir’s mechanism of action?
- Enters cell
- Phosphorylated by viral TK
- Specific for infected cells with herpes only
- Host kinases add 2nd & 3rd Phosphates
- GTP is recognized by viral DNA polymerase and is added to viral DNA
- No hydroxyl group left for further addition – chain terminator
Ganciclovir is a nucleoside analog of ____
guanosine
What is ganiclovir used to treat?
CMV
What is the mechanism of ganciclovir?
Similar mechanism as acyclovir, except it can be incorporated into host genome as well - TOXIC
Who should be treated with ganciclovir?
- BM and organ transplant patients
- immunosuppressed and people with active CMV
- CMV retinitis
