Pharmacogenetics & Pharmacogenomics Quiz
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Questions and Answers

What is the primary concern of pharmacogenetics and pharmacogenomics?

  • Adverse drug reactions (ADRs) (correct)
  • Drug effectiveness
  • Economic impact of medications
  • Societal outcomes of medication use

    • Why are adverse drug reactions (ADRs) considered a cornerstone of medical ethics?

  • To stress the importance of avoiding harm in medical interventions (correct)
  • To promote drug effectiveness in healthcare
  • To emphasize the societal outcomes of ADRs
  • To highlight the economic impact of ADRs

    • What percentage of UK hospital admissions are attributed to adverse drug reactions (ADRs)?

  • 10%
  • 5%
  • 20%
  • 15% (correct)

    • Why do ADRs have a significant economic impact?

    <p>They result in unnecessary hospital stays and costs</p> Signup and view all the answers

    What percentage of hospital inpatients experience adverse drug reactions (ADRs) during their stay?

    <p>15%</p> Signup and view all the answers

    Why are improvement efforts focused on avoidable adverse drug reactions (ADRs)?

    <p>To reduce unnecessary harm caused by medications</p> Signup and view all the answers

    What percentage of UK hospital admissions are accounted for by Adverse Drug Reactions (ADRs)?

    <p>6.5%</p> Signup and view all the answers

    Why is integrating pharmacogenomics into routine NHS practice considered important?

    <p>To provide patients with safer and more appropriate therapies</p> Signup and view all the answers

    What is the primary aim when tailoring prescription and dosage to an individual's genes?

    <p>Provide better treatment outcomes</p> Signup and view all the answers

    What does pharmacogenetics primarily study?

    <p>How variation in single genes affects responses to drugs</p> Signup and view all the answers

    What is the main focus of pharmacokinetics?

    <p>How much drug is needed to reach its target in the body</p> Signup and view all the answers

    What is the difference between pharmacogenetics and pharmacogenomics?

    <p>Pharmacogenetics studies variation in single genes, while pharmacogenomics studies how a person’s genome can influence drug responses.</p> Signup and view all the answers

    What is the overarching goal of pharmacogenomic testing in healthcare according to the text?

    <p>To reduce the variability in drug response by looking at every individual's genetic information</p> Signup and view all the answers

    What percentage of ADRs are considered avoidable?

    <p>70%</p> Signup and view all the answers

    What does pharmacokinetics encompass regarding drug action?

    <p>Drug absorption, distribution, metabolism, and excretion (ADME)</p> Signup and view all the answers

    What factor of drug action is described as the effect of a drug on its target in the body?

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

    Which enzyme action is involved in breaking down drugs in the stomach?

    <p>Cytochrome P450 enzymes</p> Signup and view all the answers

    What can happen to drugs that cannot pass the blood-brain barrier?

    <p>They do not reach the target site</p> Signup and view all the answers

    What are the potential routes for drugs to leave the body?

    <p>Bile, urine, and exhalation</p> Signup and view all the answers

    Which group of individuals are carriers of two alleles that decrease enzyme activity?

    <p>Intermediate Metabolizers (IMs)</p> Signup and view all the answers

    In pharmacogenomics, what does 'allele frequency' refer to?

    <p>How common a specific gene variant is in a population</p> Signup and view all the answers

    'Off-target' effects of drugs are primarily responsible for what?

    <p>Drug side effects</p> Signup and view all the answers

    'Clinical benefit' in pharmacogenomics is associated with which aspect?

    <p>% of people likely to have a reaction &amp; symptom severity</p> Signup and view all the answers

    'Pharmacogenes' are genes that primarily impact what?

    <p>Drug metabolism by CYP450 isoenzymes</p> Signup and view all the answers

    What can gene deletions or duplications lead to in terms of enzyme activity?

    <p>Increased enzyme activity</p> Signup and view all the answers

    Which population has the highest frequency of poor metabolizers of Cytochrome P450 activity variants?

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

    Which enzyme is involved in metabolizing certain antidepressant, antiarrhythmic, and antipsychotic drugs?

    <p>CYP2D6</p> Signup and view all the answers

    How does the genotype of the CYP2D6 locus affect drug metabolism?

    <p>It slows down drug metabolism</p> Signup and view all the answers

    What percentage of the population are classified as ultra-rapid metabolizers of codeine?

    <p>2%</p> Signup and view all the answers

    What is the enzyme targeted by Warfarin, a common anticoagulant?

    <p>VKORC1</p> Signup and view all the answers

    Which group is most commonly prescribed Warfarin?

    <p>Patients with artificial heart valves</p> Signup and view all the answers

    What can happen if a patient on Warfarin receives an incorrect dosage?

    <p>Life-threatening bleeding risks</p> Signup and view all the answers

    What is the most common cause of emergency hospitalization for ADRs in the elderly?

    <p>Incorrect dosage of medications</p> Signup and view all the answers

    Which enzyme family does CYP2B6 belong to?

    <p>Cytochrome P450 superfamily</p> Signup and view all the answers

    Which gene is associated with cystic fibrosis transmembrane conductance regulation?

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

    What is the main concern associated with HLA-B*1502 variant?

    <p>Predisposition to toxic epidermal necrolysis from carbamazepine</p> Signup and view all the answers

    Which medication is associated with a severe hypersensitivity reaction in patients with the HLA-B*5701 variant?

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

    What genetic association has been identified with immune Adverse Drug Reactions (ADRs)?

    <p>Ethnicity-specific</p> Signup and view all the answers

    What disease is more common in patients taking carbamazepine or allopurinol?

    <p>Toxic epidermal necrolysis</p> Signup and view all the answers

    Which region has a high prevalence of the HLA-B*1502 variant?

    <p>Southeast Asia</p> Signup and view all the answers

    What is the main reason for the cost-effective nature of genetic testing for HLA-B*5701?

    <p>Reduction in adverse reactions</p> Signup and view all the answers

    What is the primary route of warfarin inactivation in the liver?

    <p>CYP2C9</p> Signup and view all the answers

    Which enzyme does Warfarin inhibit?

    <p>VKORC1</p> Signup and view all the answers

    Which gene variants are primarily responsible for affecting Warfarin metabolism?

    <p>CYP2C9</p> Signup and view all the answers

    Which gene variants reduce enzyme activity and require lower dosages of Warfarin?

    <p>CYP2C9*2</p> Signup and view all the answers

    Which genetic variant has been associated with an increased risk of bleeding with Clopidogrel?

    <p>CYP2C19*17</p> Signup and view all the answers

    What is the primary enzyme responsible for converting Clopidogrel into its active form?

    <p>CYP2C19</p> Signup and view all the answers

    Which gene variants make Clopidogrel ineffective?

    <p>CYP2C19*5</p> Signup and view all the answers

    Which type of adverse reactions are induced by more than 200 chemically unrelated compounds?

    <p><strong>Type B</strong> adverse reactions</p> Signup and view all the answers

    What is the consequence of carrying a rare gene variant of the MT-RNR1 gene on mitochondrial DNA?

    <p>Potential irreversible hearing loss</p> Signup and view all the answers

    Why is it crucial for newborns with infections or sepsis to receive immediate treatment?

    <p>To increase chances of survival</p> Signup and view all the answers

    What is the purpose of the rapid pharmacogenetic test developed by the NHS for infants in intensive care?

    <p>To prevent hearing loss and enable timely antibiotic treatment</p> Signup and view all the answers

    Why are thiopurines like azathioprine, mercaptopurine, or tioguanine used in chemotherapy?

    <p>For immunosuppression</p> Signup and view all the answers

    What happens when patients have a non-functioning copy of the TPMT gene?

    <p>They develop extreme illness</p> Signup and view all the answers

    Why are some individuals with a TPMT gene variant at risk of life-threatening myelosuppression?

    <p>Lack of detectable TPMT protein in tissues</p> Signup and view all the answers

    How do many commonly-prescribed drugs like antidepressants work to be effective?

    <p>By interacting with a protein called ABCB1</p> Signup and view all the answers

    What is the role of ABCB1 in medication effectiveness?

    <p>Assisting in drug delivery to cells</p> Signup and view all the answers

    How many pharmacogenomic tests are available for variants in the ABCB1 gene?

    <p>18</p> Signup and view all the answers

    Which gene is NOT part of the pharmacodynamic genes tested alongside cytochrome P450s for psychiatric medications?

    <p>CYP2D6</p> Signup and view all the answers

    What approach is the NHS shifting towards in terms of patient care according to the Long Term Plan?

    <p>Community-based care</p> Signup and view all the answers

    What is emphasized by the NHS Long Term Plan regarding patient care?

    <p>Care closer to home</p> Signup and view all the answers

    How many CYP genes are typically tested in pharmacogenetic testing for personalized prescribing?

    <p>3</p> Signup and view all the answers

    Which of the following is not a pharmacogenomics glossary resource provided in the text?

    <p><a href="https://www.england.nhs.uk/genomics/nhs-genomic-med-service/">https://www.england.nhs.uk/genomics/nhs-genomic-med-service/</a></p> Signup and view all the answers

    Where does the NHS establish point of care testing (POCT) equipment and devices?

    <p>Community pharmacies</p> Signup and view all the answers

    Which of the following terms is NOT explained as a learning objective at the end of the lecture?

    <p><strong>genetic engineering</strong></p> Signup and view all the answers

    'How different variants affect drug metabolism' is associated with understanding the role of which enzyme?

    <p><strong>CYP2D6</strong></p> Signup and view all the answers

    Which gene variation affects the metabolism of thiopurines such as azathioprine according to the text?

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

    Study Notes

    Adverse Drug Reactions (ADRs)

    • ADRs account for 6.5% of UK hospital admissions and 15% of hospital inpatients, resulting in around 8,000 overnight stays in hospital beds per year, costing the taxpayer £1 billion.
    • Up to 70% of ADRs are avoidable, making improvement a significant interest to medics and scientists.

    Pharmacogenetics and Pharmacogenomics

    • Pharmacogenetics and pharmacogenomics are crucial in understanding the variation in response to medication, leading to poorer individual and societal outcomes.
    • The field focuses on the influence of genetic variations on drug response, metabolism, and efficacy.

    Pharmacokinetics (ADME)

    • Absorption: the process of how a drug enters the body.
    • Distribution: describes where the drug travels after absorption and how much of the drug reaches the target site.
    • Metabolism: how the drug gets broken down in the body, which can happen immediately by enzyme action in the stomach.
    • Excretion: describes how drugs leave the body, whether by urine, bile, or, in some cases, exhalation.

    Pharmacodynamics

    • Describes the effect (molecular action) of a drug on its target in the body, such as heart tissue or neurons.
    • Encompasses "off-target" effects of drugs, which are a major factor in side effects.
    • The body's ability to break down a particular drug or efficacy in drug response is markedly influenced by DNA variation.

    Cytochrome P450 Enzymes (CYPs)

    • CYPs commonly impact drug metabolism and are coded by genes that vary in the population.
    • Differential metabolism by such enzymes can lead to diverse metabolizer phenotypes, ranging from ultrarapid to poor metabolizers.
    • Proportion of drugs metabolized by CYP450 isoenzymes.

    Genotype-Phenotype Relationships

    • Genotype-phenotype relationships between variants and drug metabolism, such as alleles with gene deletions or duplications, can lead to increased enzyme activity.
    • Extensive metabolizers (EMs), intermediate metabolizers (IMs), poor metabolizers (PMs), and ultrarapid metabolizers (UMs) are classified based on genotype and phenotype.

    CYP2D6

    • CYP2D6 is a drug-metabolizing enzyme in the liver that breaks down and terminates the action of certain antidepressant, antiarrhythmic, and antipsychotic drugs.
    • 70 variant alleles have been described by molecular cloning studies.
    • Alleles with gene deletions or duplications can lead to increased enzyme activity.
    • CYP2D6 overlaps with four distinct therapeutic areas.

    Warfarin Metabolism

    • Warfarin is a common anticoagulant that prevents blood clots from forming.
    • The correct dosage of warfarin is crucial, as incorrect dosage can lead to life-threatening side effects.
    • Two types of genetic changes are involved in warfarin metabolism: those affecting the breakdown of warfarin by CYPs in the liver and those involved in how the drug slows down blood clotting.

    Immune-Mediated Adverse Drug Reactions (ADRs)

    • Severe drug-induced hypersensitivity and drug-induced liver injury are a heterogeneous group of type B or off-target adverse reactions.

    • These reactions are rare, but can be potentially lethal and have considerable economic implications.

    • The genetic association with immune ADRs can be drug-specific, phenotype-specific, or ethnicity-specific.

    • HLA alleles are strongly associated with immune ADRs.### Pharmacogenomics and Personalized Medicine

    • Pharmacogenomics is the study of how a person's genome affects their response to particular drugs.

    • It can help identify the right medication and dosage for an individual, reducing the risk of adverse drug reactions (ADRs).

    Adverse Drug Reactions (ADRs)

    • ADRs account for 6.5% of UK hospital admissions and 15% of hospital inpatients.
    • Up to 70% of ADRs are avoidable, resulting in around 8,000 overnight stays in hospital beds per year, costing the taxpayer £1 billion.
    • The goal of integrating pharmacogenomics into routine NHS practice is to provide patients with safer and more appropriate therapies, avoiding ineffective or harmful treatments.

    Pharmacogenomic Testing

    • At least 18 pharmacogenomic tests are available for variants in the ABCB1 gene, which affects the response to certain medications.
    • Pharmacogenomic testing can help reduce treatment costs in patients with mental health illness by identifying the right medication and dosage.

    Pharmacokinetics and Pharmacodynamics

    • Pharmacokinetics describes how a drug is absorbed, distributed, metabolized, and eliminated by the body.
    • Pharmacodynamics studies the effects of drugs on the body, including the intended therapeutic effects and potential ADRs.

    Genomic Variants and Drug Response

    • Genetic variants can affect drug response, leading to ADRs or reduced efficacy.
    • Different ancestries are associated with different genomic variants, requiring different approaches to monitor which medications are most likely to be linked to ADRs.

    HLA Genes and Immune-Mediated ADRs

    • HLA genes are associated with immune-mediated ADRs, such as Stevens-Johnson syndrome and toxic epidermal necrolysis.
    • Genetic testing for HLA alleles can help identify individuals at risk of ADRs and inform treatment decisions.

    Specific Medications and Genomic Variants

    • Abacavir, an antiviral medication, is associated with hypersensitivity reactions in individuals with the HLA-B*5701 variant.
    • Carbamazepine, an anticonvulsant medication, is associated with Stevens-Johnson syndrome and toxic epidermal necrolysis in individuals with the HLA-B*1502 variant.
    • Gentamycin, an antibiotic, can cause hearing loss in individuals with the MT-RNR1 genetic variant.
    • Thiopurines, such as azathioprine, are associated with toxicity in individuals with TPMT genetic variants.

    Point-of-Care Testing and Pharmacogenomics

    • The NHS is establishing point-of-care testing (POCT) in community pharmacies, including equipment and devices for diagnosis, monitoring, and screening.
    • POCT can help facilitate the integration of pharmacogenomics into routine NHS practice, providing patients with safer and more appropriate therapies.

    Future of Pharmacogenomics

    • The goal of pharmacogenomics is to move from a reactive approach, where patients are screened when they become ill, to a pre-emptive approach, where genomic data is increasingly integrated into healthcare.
    • Pharmacogenomics has enormous potential to enable more accurate prescribing, reduce waste, and improve patient outcomes.

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    Test your knowledge on pharmacogenetics and pharmacogenomics, focusing on personalized and precision medicine. Learn about the inter-personal variation in response to medication, inefficacious medication, and adverse drug reactions (ADRs).

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