Influenza Treatment and Prophylaxis
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Influenza Treatment and Prophylaxis

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Questions and Answers

What is the effectiveness of prophylaxis in preventing influenza?

  • 0-30%
  • 40-60%
  • 90-100%
  • 70-90% (correct)
  • What is the unique mechanism of action of Baloxavir Marboxil (Xofluza)?

  • Targets the ribonuclease activity that affects transcription of viral RNA (correct)
  • Inhibits the release of viral RNA
  • Prevents the replication of viral DNA
  • Enhances the immune response against the virus
  • What is the oral bioavailability of acyclovir?

  • 22% (correct)
  • 80%
  • 90%
  • 55%
  • What is the benefit of valacyclovir over acyclovir?

    <p>Higher oral bioavailability</p> Signup and view all the answers

    What is the benefit of famciclovir over acyclovir?

    <p>Higher oral bioavailability</p> Signup and view all the answers

    What is the benefit of treating genital herpes with nucleoside analogues?

    <p>Prevents replication of HSV and reduces pain and symptoms</p> Signup and view all the answers

    What is the benefit of treating shingles with nucleoside analogues?

    <p>Shortens duration of acute illness and pain</p> Signup and view all the answers

    What is the benefit of the vaccine Zostavax?

    <p>Reduces the incidence and severity of herpes zoster infections</p> Signup and view all the answers

    What is the primary characteristic that makes ganciclovir more effective against CMV than acyclovir?

    <p>Ganciclovir is 100 times more active against CMV than acyclovir</p> Signup and view all the answers

    What is the primary use of cidofovir?

    <p>IV treatment of CMV disease, including retinitis and colitis</p> Signup and view all the answers

    Which of the following drugs is available in an ophthalmic gel formulation?

    <p>Ganciclovir</p> Signup and view all the answers

    What is the primary indication for trifluridine?

    <p>Treatment of herpetic epithelial keratitis and keratoconjunctivitis</p> Signup and view all the answers

    Which of the following adverse reactions is associated with foscarnet?

    <p>All of the above</p> Signup and view all the answers

    What is the advantage of combining foscarnet with ganciclovir?

    <p>Treatment of infections resistant to either drug alone</p> Signup and view all the answers

    What is the primary route of administration for foscarnet?

    <p>Intravenous</p> Signup and view all the answers

    Which of the following is NOT a characteristic of trifluridine?

    <p>Available in oral formulation</p> Signup and view all the answers

    Which enzyme is involved in the replication of HIV genetic material into host DNA?

    <p>Reverse transcriptase</p> Signup and view all the answers

    What is the primary goal of highly active antiretroviral therapy (HAART)?

    <p>To reduce the viral load and improve survival</p> Signup and view all the answers

    Which of the following is NOT a step in the pathophysiology of HIV?

    <p>Viral RNA production</p> Signup and view all the answers

    What is the primary mechanism of action of non-nucleoside reverse transcriptase inhibitors (NNRTIs)?

    <p>Non-competitive inhibition of reverse transcriptase</p> Signup and view all the answers

    Which drug class does Atripla belong to?

    <p>Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs)</p> Signup and view all the answers

    What is the result of HIV protease cleaving polyproteins?

    <p>Mature virions</p> Signup and view all the answers

    What is the primary advantage of recent HAART regimens?

    <p>Simplified dosing schedules</p> Signup and view all the answers

    Which of the following is NOT a drug class used to treat HIV?

    <p>Kinase inhibitors</p> Signup and view all the answers

    Which of the following is NOT a type of Reverse Transcriptase inhibitor?

    <p>Protease inhibitors (PI)</p> Signup and view all the answers

    What is the mechanism of action of NRTIs?

    <p>Both A and B</p> Signup and view all the answers

    Which of the following NRTIs is classified as a nucleotide RTI?

    <p>Tenofovir disoproxil fumarate (TDF)</p> Signup and view all the answers

    What is the usual combination of drugs in the initial treatment of HIV?

    <p>Two NRTIs with an NNRTI</p> Signup and view all the answers

    What is the common adverse effect of all NRTIs?

    <p>Lactic acidosis, hepatic steatosis and lipodystrophy</p> Signup and view all the answers

    Which of the following is NOT a combination drug containing AZT?

    <p>Ziagen</p> Signup and view all the answers

    What is the benefit of AZT treatment in pregnant women with HIV?

    <p>Reduces the risk of in utero transmission of HIV</p> Signup and view all the answers

    What is the advantage of Atripla over other NRTI combinations?

    <p>It contains an NNRTI in addition to two NRTIs</p> Signup and view all the answers

    What is the primary function of integrase inhibitors in the treatment of HIV?

    <p>Prevent DNA strand transfer</p> Signup and view all the answers

    Which of the following medications is not a combination of ritonavir and another PI?

    <p>Isentress</p> Signup and view all the answers

    What is the characteristic of enfuvirtide that makes it less convenient for patients?

    <p>It must be injected subcutaneously twice daily</p> Signup and view all the answers

    What is a benefit of maraviroc and other fusion and entry inhibitors?

    <p>They are active against HIV strains resistant to RTIs and PIs</p> Signup and view all the answers

    What is the term for the process inhibited by integrase inhibitors?

    <p>DNA strand transfer</p> Signup and view all the answers

    What is the benefit of using raltegravir in initial treatment regimens?

    <p>It is a valuable option for patients with HIV strains resistant to RTIs and PIs</p> Signup and view all the answers

    What is a common side effect of enfuvirtide?

    <p>Injection site reactions</p> Signup and view all the answers

    What is the characteristic of enfuvirtide that makes it a valuable treatment option?

    <p>It is active against HIV strains resistant to RTIs and PIs</p> Signup and view all the answers

    Study Notes

    Influenza Treatment

    • Oseltamivir may still provide benefit in reducing respiratory failure and death in pregnant women if started 3-4 days after onset.
    • Prophylaxis is 70-90% effective in preventing influenza and is a useful adjunct to vaccines, but the CDC recommends against it due to the risk of resistance.
    • Prophylaxis is only recommended for populations at risk of complications and to control institutional outbreaks.

    Baloxavir Marboxil (Xofluza)

    • Single-dose PO treatment for influenza A and B.
    • First-in-class medication with a unique MOA that targets ribonuclease activity affecting transcription of viral RNA.
    • Approved in the US in 2018 and potentially has fewer side effects compared to oseltamivir.

    Herpesvirus Infections

    • Cytomegalovirus (CMV) infections are usually asymptomatic in immunocompetent individuals, but can cause retinitis, esophagitis, and colitis in immunocompromised patients.

    Nucleoside Analogues

    • Acyclovir (Zovirax) is effective in treating serious herpesvirus infections, including encephalitis and infections in immunocompromised patients.
    • Topical acyclovir can be used to treat genital herpes and mild mucocutaneous infections, but is less effective than oral treatment.
    • Valacyclovir (Valtrex) is a prodrug that gets rapidly converted to acyclovir and has more complete absorption (55%) compared to acyclovir (22%).
    • Famciclovir (Famvir) has the greatest bioavailability (80%) and gets rapidly hydrolyzed to penciclovir after absorption.

    Other Drugs

    • Foscarney (Foscavir) is used to treat CMV retinitis in AIDS patients and acyclovir-resistant HSV infections and shingles.

    Treating Genital Herpes

    • Oral treatment with acyclovir, valacyclovir, or famciclovir prevents replication of HSV, reduces pain and symptoms of acute infection, and shortens the time to healing of lesions and reduces viral shedding.
    • Does not eliminate the virus, and recurrent episodes are common.

    Treating Shingles

    • Oral treatment with acyclovir, valacyclovir, or famciclovir shortens the duration of acute illness and pain and lowers the incidence of postherpetic pain.
    • Famciclovir and valacyclovir are more effective than acyclovir, and newer drugs have less frequent administration and higher serum levels.
    • A vaccine is now available (Zostavac) that reduces the incidence and severity of herpes zoster infections in older adults.

    Treating CMV

    • Nucleoside analogues are used to prevent and treat CMV disease, including retinitis, esophagitis, and colitis.
    • Ganciclovir is 100 times more active against CMV than acyclovir.

    HIV Infection

    • Combined use of 2 or more drugs from different classes has been shown to markedly reduce viral load and improve survival.
    • Multidrug treatment called highly active antiretroviral therapy (HAART) has been developed.

    HAART

    • Initially, complicated regimens required multiple doses of several drugs every day, but recent emphasis is on developing drug regimens that require only a few doses each day or even a single pill (like atripla).
    • Guidelines continue to evolve as new regimens are developed and testing improves.

    Pathophysiology of HIV

    • HIV enters CD4 cells, and viral RNA is produced, which gets converted to double-stranded DNA via reverse transcriptase.
    • Viral DNA enters the host cell nucleus and gets incorporated into the host genome via HIV integrase.
    • Eventually, the viral DNA gets transcribed/translated to produce polyproteins that get packed into immature virions.

    Drug Classes

      1. Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs)
      1. Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
      1. Protease inhibitors (PIs)
      1. Fusion and entry inhibitors
      1. Integrase strand transfer inhibitors

    Reverse Transcriptase Inhibitors

    • NRTIs are converted to active triphosphate metabolites by host cell kinases, which compete with corresponding endogenous nucleoside triphosphate for incorporation into DNA, causing chain termination.

    Nucleoside vs Nucleotide

    • Tenofovir disoproxil fumarate (TDF) is classified as a nucleotide RTI, which gets hydrolyzed in the body to form tenofovir.

    Nucleoside Transcriptase Inhibitors (NRTIs)

    • First class of drugs developed for treating HIV+ individuals.
    • Included in almost all regimens.
    • Serve as antimetabolites for different purine and pyrimidine bases of DNA.
    • Often more effective when combined with other NRTIs.

    Fusion and Entry Inhibitors

    • Enfuvirtide (Fuzeon) is a large peptide that binds to HIV glycoprotein 41 and blocks the fusion process.
    • Maraviroc (Selzentry) is a newer drug that inhibits fusion and entry of HIV.
    • Active against HIV strains resistant to RTIs and PIs.

    Integrase Inhibitors

    • Raltegravir (Isentress) is the first integrase strand inhibitor approved to treat HIV.
    • Works by preventing DNA strand transfer.
    • Potent in vitro activity against wild-type and MDR HIV strains.

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    Description

    This quiz covers the treatment and prophylaxis of influenza, including antiviral medications and their effectiveness in preventing respiratory failure and death.

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