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Questions and Answers
Nucleoside Reverse Transcriptase Inhibitors (NRTIs) require phosphorylation to become active.
Nucleoside Reverse Transcriptase Inhibitors (NRTIs) require phosphorylation to become active.
True
Efavirenz is known to cause gastrointestinal intolerance as a primary side effect.
Efavirenz is known to cause gastrointestinal intolerance as a primary side effect.
False
Protease inhibitors are crucial for allowing the cleavage of polypeptide products derived from HIV mRNA into functional viral proteins.
Protease inhibitors are crucial for allowing the cleavage of polypeptide products derived from HIV mRNA into functional viral proteins.
False
Entry inhibitors like Enfuvirtide specifically target the HIV protease enzyme.
Entry inhibitors like Enfuvirtide specifically target the HIV protease enzyme.
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Integrase Strand Transfer Inhibitors (INSTIs) inhibit the virus's ability to integrate its DNA into the host cell DNA.
Integrase Strand Transfer Inhibitors (INSTIs) inhibit the virus's ability to integrate its DNA into the host cell DNA.
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All Antiretroviral Therapies (ART) are effective against both HIV-1 and HIV-2 without any exceptions.
All Antiretroviral Therapies (ART) are effective against both HIV-1 and HIV-2 without any exceptions.
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Nephrotoxicity is a potential side effect of Zidovudine.
Nephrotoxicity is a potential side effect of Zidovudine.
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A typical ART regimen usually consists of two drugs to minimize resistance.
A typical ART regimen usually consists of two drugs to minimize resistance.
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Tenofovir is a nucleoside that does not require phosphorylation to become active.
Tenofovir is a nucleoside that does not require phosphorylation to become active.
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Efavirenz is associated with vivid dreams and central nervous system symptoms.
Efavirenz is associated with vivid dreams and central nervous system symptoms.
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Integrase inhibitors allow HIV virions to efficiently integrate their DNA into the host genome.
Integrase inhibitors allow HIV virions to efficiently integrate their DNA into the host genome.
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Entry inhibitors like Maraviroc block the gp120 protein to prevent HIV entry into cells.
Entry inhibitors like Maraviroc block the gp120 protein to prevent HIV entry into cells.
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Protease inhibitors are crucial for the formation of functional HIV virions by enabling protease activity.
Protease inhibitors are crucial for the formation of functional HIV virions by enabling protease activity.
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Patients undergoing antiretroviral therapy typically require a regimen consisting of four drugs for optimal efficacy.
Patients undergoing antiretroviral therapy typically require a regimen consisting of four drugs for optimal efficacy.
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Hepatotoxicity is a common side effect associated with the use of NNRTIs.
Hepatotoxicity is a common side effect associated with the use of NNRTIs.
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Myelosuppression resulting from NRTIs can be reversed.
Myelosuppression resulting from NRTIs can be reversed.
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Tenofovir is a non-nucleotide analog that requires phosphorylation to become active.
Tenofovir is a non-nucleotide analog that requires phosphorylation to become active.
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Protease inhibitors play a crucial role in allowing the cleaving of polypeptide products derived from HIV mRNA into functional viral proteins.
Protease inhibitors play a crucial role in allowing the cleaving of polypeptide products derived from HIV mRNA into functional viral proteins.
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NNRTIs require phosphorylation for activation in the same manner as NRTIs.
NNRTIs require phosphorylation for activation in the same manner as NRTIs.
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Myelosuppression caused by NRTIs is irreversible and poses a significant risk to patients.
Myelosuppression caused by NRTIs is irreversible and poses a significant risk to patients.
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Integrase Strand Transfer Inhibitors (INSTIs) target the protease enzyme to prevent HIV replication.
Integrase Strand Transfer Inhibitors (INSTIs) target the protease enzyme to prevent HIV replication.
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Efavirenz is associated with vivid dreams and central nervous system side effects.
Efavirenz is associated with vivid dreams and central nervous system side effects.
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Entry inhibitors like Enfuvirtide facilitate the entry of HIV into host cells by targeting membrane proteins.
Entry inhibitors like Enfuvirtide facilitate the entry of HIV into host cells by targeting membrane proteins.
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A typical antiretroviral therapy regimen consists of two drugs to prevent resistance.
A typical antiretroviral therapy regimen consists of two drugs to prevent resistance.
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Study Notes
Nucleoside Reverse Transcriptase Inhibitors (NRTIs)
- NRTIs block HIV replication by mimicking natural nucleotides, preventing reverse transcriptase from elongating the viral DNA chain.
- Tenofovir is a nucleotide analog, while others are nucleosides that require phosphorylation to become active.
- NRTIs can cause side effects like nephrotoxicity, pancreatitis, and myelosuppression.
- Some specific contraindications exist for certain NRTIs: Abacavir in individuals with HLA-B*5701 and Zidovudine in patients with macrocytic anemia.
Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)
- NNRTIs bind to reverse transcriptase at a distinct site compared to NRTIs, causing a conformational change that inhibits the enzyme and viral replication.
- Unlike NRTIs, they don't need to be phosphorylated to become active.
- Rash, hepatotoxicity, and CNS symptoms (particularly with Efavirenz) are common side effects.
Integrase Strand Transfer Inhibitors (INSTIs)
- INSTIs target integrase, a crucial enzyme for HIV's integration into the host cell's DNA.
- By inhibiting integrase activity, INSTIs prevent the viral DNA from integrating into the host cell's genome, halting replication.
- Common side effects include increased creatine kinase and weight gain.
Protease Inhibitors
- Protease inhibitors block the formation of functional HIV virions by preventing the protease enzyme from cleaving viral proteins.
- Viral proteases are essential for producing mature, infectious HIV particles.
- Side effects include hyperglycemia, gastrointestinal intolerance (nausea, diarrhoea), and increased protease inhibitor concentrations in the bloodstream.
Entry Inhibitors
- Entry inhibitors prevent HIV from entering the host cell by targeting specific viral proteins.
- Enfuvirtide, for example, interferes with gp41, preventing membrane fusion and entry of the virus.
- Skin reactions at injection sites are a common side effect of Enfuvirtide.
Important Considerations
- Most HIV ART regimens consist of three drugs to minimize the risk of viral resistance.
- The majority of ARTs are effective against both HIV-1 and HIV-2, though some exceptions exist.
- Some drugs can be used for PrEP (pre-exposure prophylaxis) to prevent HIV acquisition.
- The most appropriate ART regimen is chosen based on individual factors, including viral load, CD4 count, and co-morbidities.
Nucleoside Reverse Transcriptase Inhibitors (NRTIs)
- Inhibit HIV replication by competitively binding to reverse transcriptase, halting DNA chain elongation.
- Tenofovir is a nucleotide analog, others are nucleosides that require phosphorylation for activation
- Side effects include nephrotoxicity, pancreatitis, and myelosuppression
- Contraindications include Abacavir (with HLA-B*5701) and Zidovudine (macrocytic anemia)
Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)
- Bind to reverse transcriptase at a different site than NRTIs, inducing a conformational change that inhibits activity.
- Do not require phosphorylation for activation.
- Side effects include rash, hepatotoxicity, and vivid dreams (Efavirenz).
Integrase Strand Transfer Inhibitors (INSTIs)
- Inhibit the integrase enzyme, which HIV uses to insert its viral DNA into the host cell's DNA.
- Without integration, the HIV lifecycle cannot proceed.
- Side effects include increased creatine kinase and weight gain.
Protease Inhibitors
- Block the formation of functional HIV virions by preventing the protease enzyme from cleaving viral polypeptide products into functional proteins.
- This results in immature and non-infectious HIV particles.
- Side effects include hyperglycemia, GI intolerance, and increased protease inhibitor concentrations.
Entry Inhibitors
- Prevent HIV from entering the host cell by targeting gp41 and inhibiting membrane fusion.
- Side effects include skin reactions at injection sites (Enfuvirtide).
Important Considerations
- Most ART regimens consist of three drugs to prevent resistance.
- Most ARTs are active against both HIV-1 and HIV-2, with exceptions.
- Some drugs can be used as pre-exposure prophylaxis (PrEP).
- The choice of drugs should consider patient factors including viral load, CD4 count, and co-morbidities.
Nucleoside Reverse Transcriptase Inhibitors (NRTIs)
- NRTIs competitively inhibit reverse transcriptase by binding to the enzyme’s active site, preventing the incorporation of nucleotides into the viral DNA chain.
- Tenofovir is a nucleotide analog, meaning it is directly incorporated into DNA, while other NRTIs are nucleosides that require phosphorylation to become active.
- Common side effects include nephrotoxicity, pancreatitis, and myelosuppression, but myelosuppression is reversible.
- Abacavir is contraindicated in individuals with the HLA-B*5701 allele, and zidovudine can lead to macrocytic anemia.
Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)
- NNRTIs bind to reverse transcriptase at a different site than NRTIs, leading to a conformational change that inhibits the enzyme's activity.
- This non-competitive inhibition prevents viral replication without requiring phosphorylation for activation.
- Side effects include rash, hepatotoxicity, and, in the case of efavirenz, vivid dreams and central nervous system symptoms.
Integrase Strand Transfer Inhibitors (INSTIs)
- Integrase is an essential enzyme used by HIV to integrate its viral DNA into the host cell's genome, enabling replication.
- INSTIs inhibit integrase activity, preventing the integration of viral DNA and halting the HIV lifecycle.
- Common side effects include increased creatine kinase levels and weight gain.
Protease Inhibitors
- Protease inhibitors block the formation of functional HIV virions by inhibiting the protease enzyme.
- Protease is crucial for cleaving large polypeptide products from HIV mRNA into functional viral proteins.
- Without proper cleavage, newly produced HIV particles remain immature and non-infectious, preventing the spread of the virus.
- Side effects include hyperglycemia, gastrointestinal intolerance, and increased protease inhibitor concentrations.
Entry Inhibitors
- Entry inhibitors prevent HIV from entering host cells by targeting specific proteins involved in the viral entry process.
- For example, enfuvirtide targets gp41, a protein essential for membrane fusion.
- The main side effect of enfuvirtide is a skin reaction at the injection sites.
General Considerations
- Antiretroviral therapy (ART) regimes typically consist of three drugs to minimize the development of drug resistance.
- Most ART drugs are effective against both HIV-1 and HIV-2, with some exceptions.
- Certain drugs can be used for pre-exposure prophylaxis (PrEP) to prevent HIV infection.
- The selection of ART drugs should consider individual patient factors, including viral load, CD4 count, and the presence of co-morbidities.
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Description
This quiz covers key aspects of antiretroviral drugs, focusing on Nucleoside Reverse Transcriptase Inhibitors (NRTIs), Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs), and Integrase Strand Transfer Inhibitors (INSTIs). You'll learn about their mechanisms of action, side effects, and contraindications, enhancing your understanding of HIV treatment options.
