Antiviral Drugs Flashcards
How do we treat viruses indirectly?
Hygeine, detergents, cryotherapy
How do we treat them directly?
Immunomodulation and antivirals
What are the major classes of antivirals?
Nucleoside analogs, non-nucleosides, protease inhibitors, and entry inhibitors
How do anitvirals work?
target an essential microbial function
What functions are targeted by small molecules?
entry, genome replication
Can antiviral drugs target host cells? How?
Yes; target interferon response
How can entry in cell be blocked?
entry inhibitors (infrubatide for HIV chemokine receptors)
How can viruses be blocked upon entry?
Block uncoating, but these drugs are widely ineffective now due to viral resistance, not prescribed
What is the most effective target for viral inhibition?
Nucleic acid synthesis (nucs, non-nucs) protease inhibitors
What blocks the assembly of the viral particle
Protease inhibitors
What are release inhibitors?
neurominidase blocking inhibitors
WHat is intrinsic immunity?
immunity that lives within the cell itself
What is peggalted interferon target?
k
Why is thymidine kinase?
It is a common target of antivirus drugs
What are the 3 major issues about antivirals?
Specificity, cytotoxicity, and duration of antiviral effects
What happens when the drug is removed? What is an implication of that effect?
Virus replication can resume when the drug is cleared; means treatment must be life long
When does resistance to antivirals often occur? Why is this problematic?
Resistance mutations often exist in a patient before drug treatment; selects for the resistant viral strains
What factors favor the emergence of resistant variants?
High rate of viral replication
high mutation rate
high selective drug pressure
immunosuppressed host
Which types of viruses mutate faster?
RNA viruses because they are less stable
How do you prevent antiviral resistance?
You stop and start the drug to prevent the mutant strain from outcompeting the wild type strain, but then you need to give multiple drugs at once
How do you counter resistance to antivirals?
Alleviate immunosuppresion in the treated person, combine drugs with different targets that can synergize, target host function
What is acyclovir?
number one drug for HSV1 and HSV2```
Who should be treated?
recommended for neonatal anti
Describe the mechanism for acyclovir?
guanadine analog gets triphosphorylated by the Thymidine Kinase enzyme and it becomes incorporated into the DNA backbone via viral polymerase and takes away the ability of the synthesized strand to be elongated–>chain terminator
