Antivirals Flashcards
Inhibitors of viral replication
– every step in viral replication is potentially a target
– targeting host cell functions is generally not feasible (toxicity)
Antiviral Treatment
What do all these drugs have in common?
Maraviroc
Amantadine
Rimantadine
Enfuvitide
They are antivirals used to prevent virus entry
HIV fusion inhibitor
Binds to gp41 region that folds back onto itself Prevents fusion of membranes Very specific to HIV
Enfuvitide`
this antiviral is a CCR5 binding inhibitor
Maraviroc
• used to prevent
influenza
infections
• blocks penetration
and uncoating of
influenza A virus
Amantadine
______ is an analog to amantadine
Rimantadine
_______ and______ affect M2 ’s function as an ion channel
Amantadine
rimantadine
t/F: Following endocytosis, acidification of endosomes occurs Then M2 can function as ion channel Acidification within virion drives viral disassembly
true
______ _______ (mAb) binds SARS-CoV-2 virions and “neutralizes” them, which means it blocks the virus from interacting with ACE2 receptors and entering cells
Monoclonal antibody
Result of rational drug design (nucleoside analog) target herpesviruses Inhibits DNA synthesis
Acyclovir
t/f: acyclovir has no effect on latency
true
_____ is not effective against CMV
cytomegalovirus
Acyclovir
_______ is effective against CMV compared to acyclovir, although it is also more toxic (cellular TK uses drug better too).
Ganciclovir
________ is nucleoside analog
Gancicivir
- Directly inhibits herpesvirus and cytomegalovirus DNA polymerase (nephrotoxicity issues)
- is a non-
nucleoside inhibitor
Foscarnet
_________ is a nucleoside analog
interferes with the action of viral RNA-dependent RNA polymerase causes RNA synthesis termination
Remdesivir
_____ ______: cleaves viral proteins to their final mature sizes
Viral protease
What are the two examples of the newer 2-drug combination therapies target specific HCV enzymes
Inhibitor of RNA-dependent RNA polymerase
target viral protease
______ is a relatively broad-spectrum anti-DNA virus drug
Cidofovir
- in hibits viral DNA polymerase
- Use is mainly limited to cytomegalovirus retinitis in AIDS patients (toxicity limits dosage levels)
- is a nucleoside analog
Cidofovir
Need to be phosphorylated by cellular enzymes before being used by HIV reverse transcriptase (RT) (like acyclovir). HIV RT uses these analogs and since they lack a 3’ –OH, DNA synthesis (reverse transcription) stops
nucleoside analog reverse transcriptase inhibitors (NRTI)
Act like NRTI but do not need to be phosphorylated (already contain phosphate)
nucleotide analog reverse transcriptase inhibitors (NtRTI)
Bind sites on HIV RT enzyme that cause it to stop functioning, blocking reverse transcription
nonnucleoside reverse transcriptase inhibitors (NNRTI)
HIV protease cleaves the initial HIV proteins to their final mature sizes Protease inhibitors attempt to mimic an HIV protease cut site, competitively inhibiting HIV protease
Protease inhibitors
at least 3 drugs in combination
2 nucleoside inhibitors plus a NNRTI or a protease inhibitor
HAART = highly active antiretroviral therapy
- Blocks integration of HIV dsDNA into host cell chromosomal DNA
- Interferes with the strand transfer step
Integrase inhibitors
What steps of HIV replication/infection are targeted by anti-viral therapies?
Entry
Reverse Transcription
Intergration
Maturation
release of virus from envelope
cleaves sialic acid (NA has enzymatic activity)
Inhibitors prevent efficient spread of virus from cell to cell.
Neuraminidase inhibitors -
influenza virus
neuraminidase (NA)
_______ assist the immune response.
- inhibit viral replication within host cells
- activate natural killer cells and macrophages
- increase antigen presentation to lymphocytes
Interferons
What are the effects of interferon therapy?
- Fatigue
- Fever
- Myalgias
• Formerly main treatment
for hepatitis C Virus (HCV)
infection
• Formerly used for HBV
interferon therapy
• Purine nucleoside analog • Inhibits many RNA viruses and
some DNA viruses
– Influenza A and B – Measles – Respiratory Syncytial Virus
Ribavirin
