Pharm 2 - Antivirals Review

drraythe's version from 2015-11-24 01:13


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Key notes: DRUG TARGETS FOR ANTIVIRAL THERAPY (8)(1) Co-receptor antagonists (chemokine receptor)
(2) Fusion inhibitors
(3) Reverse transcriptase inhibitors
(4) Integrase inhibitors
(5) Protease inhibitors
(6) Inhibitors of coat assembly
(7) Neuramidase inhibitors
(8) Biopharmaceuticals & immunomodulators
Key note: Antiviral therapy for Herpesvirus infxns → Pyrimidine nucleosides (do what? What are the 3 main drugs in this category, & the subtypes of the 1?)Inhibition of viral DNA polymerase. (1) Idoxuridine
(2) Trifluridine
(3) Sorivudine (phosphorylation by viral enzymes: Thymidine & thymidylate kinases) (I'd tri prym sorority thys)
Key note: Antiviral therapy for Herpesvirus infxns → Purine nucleosides (do what? What are the 5 drugs in this category?)Inhibit viral DNA polymerase
(1) Vidarabine
(2) Acyclovir - Valacyclovir (pro-drug): Small spectrum
(3) Penciclovir - Famciclovir (pro-drug): Small spectrum
(4) Ganciclovir: Small spectrum
(5) Ribavirin (Gan's pure-ace rib video penetrated the web)
All the Herpes fighters (Pyrimidine & Purine) both do what?Inhibit viral DNA polymerase


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NRTIs work against what?RETROVIRUSES
MOA of NRTIs?NRTIS undergo phosphorylation by host cell enzymes & bcms a triphosphate form. This form competes w/ host cell triphosphates that viruses use to syn DNA. The NRTIs triphosphate form is incorporated into the growing viral DNA chain resulting in termination. (Retros are IN the DNA, so this has to wedge in the DNA to stop it)
ZIDOVULDINE (AZT) what is the admin w/ the best bioavailability?95% oral bioavailability (remember zardoz's giant mouth)
What is the plasma conc (EC50) like for Zidovuldine (AZT)[Plasma] Remain above EC50 for more than 12 hours (have to go from A→Z. takes a long time)
What is the half-life of Zidovuldine like?SHORT half-life of 1-4 hours (Long plasma, short half-life? Odd...)
Is Zidovuldine more or less powerful than the other NRTIs? Against what?More potent than Lamivudine against FIV in vitro (FIV wont lead to Z w/ Zidovuldine! ZARDOZ is POWERFUL & evil....gave cats AIDS)
What is the SFx of Zidovuldine?Hemolysis after IV injxn (inject slowly) (ZARDOZ will DESTROY YOUR BLOOD if he touches it)
What are the uses for Zidovuldine?FeLV, FIV, BoLV
LAMIVUDINE → is it more or less effective than Zidovuldine? Against what?Less potent than Zidovuldine against FIV in vitro
Is Lamivudine more or less safe than Zidovuldine?Lami has a better safety profile than zido (lame that it plays it wonder it isnt as powerful)
What are the 3 drugs in NRTI we care about?Lamivudine, Zidovuldine, & Stampidine (Did Zido stamp lamps for 5 FeLVors? Or Dr. Zardoz will stamp out the lame ones)
How to remember the drugs in this group?VUL is in both of the important ones...(Did Zido stamp lamps for 5 FeLVors? Or Dr. Zardoz will stamp out the lame ones)


Question Answer
This category used against what?HERPES infxns
MOA of viral DNA polymerase inhibitors? Explain how this doesnt hurt the host?Converted into monophosphate (MP) by Viral Thymidine Kinase (only in infected cells!!) → The host cell converts MP to triphosphate (active form) that inhibits viral DNA polymerase. 30x more potent against Herpes virus enzyme than host enzymes so not as toxic to host!!
What are viral DNA polymerase inhibitors good against?Effective against EHV & FHV
ACYCLOVIR → what is the PK like of this drug, compared to others in the group?Analogues & Prodrugs have better PK (Valacyclovir, Peciclovir, Famciclovir) (ace isnt the ace.....go figure.)
What is the oral bioavailability like for Acyclovir?Variable oral bioavailability (Dogs > 80%, Horses < 5%) (Ace would rather put his hand in the mouth of a dog rather than a horse)
What is the half-life like for Acyclovir?Half-life variable (Dogs = 2.3 hr, Horses = 5-9 hr, Cats = 2.5 hr) (Ace's life depends on the adventure)
Uses for Acyclovir?EHV-1, FHV, CHV & Neonatal Herpes virus in horses (~26% oral bioavailability) (higher bioavail in neonates bc not full gut closure → more drug into system) (Herpes is a vicious CYCLE of being spread around)
What to know about VALACYCLOVIR?Toxic to cats (Valarie doesnt like cats bc theyre PECky)
PENCLOVIR is used for what?Only use topically in cats (little kid drawing on cat w/ a pen)
What to know about FAMCICLOVIR?Questionable efficacy (that family is questionable)
What are the drugs listed in the DNA polymerase inhibitors category?ACYCLOVIR, VALACYCLOVIR, PENCLOVIR, FAMCICLOVIR, IDOXURIDINE, RIBAVIRIN, TRIFLURIDINE, FOSCARNET (FeLV) (Polly loves clovers)


Question Answer
What are these used against?INFLUENZA (the flu makes you feel like youre breathing acid)
MOA?Viral Hemagglutinin attaches to host neuraminic acid & enters through endocytosis. The endosome is acidified after the influx of H+ through the M2 ion channel. This allows disassembly of the viral structure & RNA release.
Note about resistance in M2-ion channel inhibitors?Use in poultry responsible for resistant strains in China? (Harmful acid chicken from China)
What are the 2 drugs in this category?AMANTADINE, RIMANTADINE (WE DINE ON Amanda started rimming)
Amantadine → admin? Use? Which animal is this best in? SFx?NOT good oral admin (Amanda needs to keep her mouth shut), Used to Tx influenza A (amantadine, a) & PAIN (watching the AMANDA show is painful) pain via NMDA receptor antagonist (ketamine) (AMANda is on ketamine, so she doesnt feel pain from her flu) → Relief of pain symptoms → Combined w/ NSAIDS. Well tolerated in dogs. This drug is TOXIC (AMANda is a toxic person w/ her drug use & influenza)
RIMANTADINE → admin? Uses?Better oral admin than Amantadine (rim & mouths. hur.) & used for EQUINE influenza (M2 ions are all influenza, but ANAL RIM on a horse is....apparently better, since the oral avail is better)


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What are the drugs in this category?ZANAMIVIR & OSELTAMIVIR


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MOA of RIBAVIRIN?Inhibits replication of a wide variety of DNA & RNA viruses (very flexible ribs) w/ MULT SITES OF ACTION
Uses of Ribavirin?HERPES, influenza A & B
SFx of Ribavirin?Toxic in cats. In vivo not used in dogs & cows (dont crack a cats ribs)
INTERFERONS → based off of what types of interferons?ω (omega)
MOA of interferons?Anti-viral by promoting the synthesis of enzymes that interfere w/ viral replication (protein synthesis & degradation of viral RNA)
In general, "how much" interferon do you need?A little goes a long way! → Cell-cell interaction converts antiviral effects w/o additional interferon
Aside from antiviral, what other properties do interferons have?Immunomodulation & anticancer properties

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