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28 Cards in this Set
- Front
- Back
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The “best” antiviral drugs do what?
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The "best" antiviral drugs selectively inhibit a specific step in viral replication or pathogenesis
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In drug discovery, what does Screening require?
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Screening requires an assay and random chemicals off the shelf
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In drug discovery, what does Rational design require?
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Rational design requires knowledge of the structure and/or mechanism of activity of a virus-specific function to enable the design of a specific inhibitory compound
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What is Acyclovir used to treat?
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Effective against HSV and less so, but active, against VZV
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How does Acyclovir inhibit viral DNA synthesis?
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Acyclovir is efficiently phosphorylated to the monophosphate form by virally-encoded thymidine kinase (tk), resulting in DNA chain termination
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What is Ganciclovir used to treat?
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Ganciclovir is used to treat Cytomegalovirus (CMV) infections
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What are two newer oral prodrugs for the treatment of herpesvirus infections?
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Famciclovir/Valacyclovir
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What is Vidarabine used to treat?
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Herpes keratitis as a topical
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Why is the drug Cidofovir mildly interesting?
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Cidofovir is the first antiviral nucleotide analogue available for the treatment of CMV retinitis. Cidofovir does not require viral activation and has the advantage of being active in uninfected cells and may act preemptively.
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What is Foscarnet (PFA) used for?
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Herpesviruses (esp. when resistant to ganciclovir), Hepatitis B, and reverse transcriptase of HIV
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What is a drawback of Foscarnet (PFA)?
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Foscarnet (PFA) is reserved for life-threatening infections because of kidney toxicity
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What is Rimantadine’s action?
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Rimantadine inhibits transmembrane ion channels formed by viral M2 protein
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What is Rimantadine’s mechanism?
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Blocks ion channel activity: prevents M1 protein dissociation from the viral ribonucleoprotein (prevents transport to the nucleus) also inhibits conformational maturation of new HA molecules.
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What is Rimantadine used for?
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Rimantadine is active for flu A (mainly as prophylaxis) but NOT B
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How does Zanamivir (inhalable: Relenza, pill form: Tamiflu) act?
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Inhibitor of the viral neuraminidase of types A and B influenzaviruses
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What is the action of Ribavirin?
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Ribavirin inhibits the growth of a wide spectrum of RNA and DNA viruses
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What’s the catch when using Ribavirin?
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Ribavirin works well in tissue culture and experimental animals, but is less effective in humans
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What are two ways that Ribavirin is used?
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1. an aerosolized formulation of Ribavirin is the only drug approved for treatment of RSV pneumonia in the U.S.
2. a Ribavirin oral pill was approved in ’98 as part of a new combination therapy for hepatitis C which includes injectable Intron A (Interferon alpha-2b) |
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What drug is approved to treat HCV, HBV, and HPV?
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Interferon
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What is Interferon alpha-2b used to treat?
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Chronic hepatitis B and C
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What is the mechanism of action of Interferons?
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Interferon mechanism of action is multiple and poorly understood although inhibition of translation of viral RNA is one
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What is CytoGam?
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An intravenous immune globulin enriched in antibodies against cytomegalovirus (CMV) and is indicated for prophylaxis against CMV disease associated with transplantation of kidney, lung, liver, pancreas, and heart
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What is RespiGam?
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A polyclonal antibody used to prevent serious lower respiratory tract infection by RSV in infants and bone marrow recipients
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What is Synagis (palivizumab) and what is it used for?
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Anti-F reactive antibody, indicated for the prevention of serious lower respiratory tract disease caused by RSV in pediatric patients at high-risk of RSV
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How does Zidovudine (AZT) inhibit DNA synthesis?
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AZT is efficiently phosphorylated to triphosphate by cellular kinases.
Viral reverse transcriptase incorporates it 100x more efficiently than cellular DNA polymerase α) into viral DNA and the chain is terminated. |
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What are some of the viral processes used as drug targets?
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Penetration
Uncoating Reverse transcription Nuclear transport Integration Transcription Tat trans-activation Rev mediated RNA transport Glycosylation and cleavage Translation Glycosylation and cleavage Particle assembly Budding |
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What practices encourage emergence of drug resistant variants?
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Chronic therapy and sub-optimal dosing
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In what type of therapy is emergence of drug resistant variants less likely?
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Combination therapy
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