Pharmacogenomics (PGx) is at the forefront of personalized medicine, empowering pharmacists to tailor drug therapy based on an individual’s genetic profile to maximize efficacy and minimize risk. In the realm of gastroenterology, PGx plays a crucial role in optimizing some of the most commonly prescribed medications. As detailed in the Patient Care 4 curriculum, understanding the “Pharmacogenomics for Gastrointestinal Disorders” is essential for modern practice. This quiz will test your knowledge of key gene-drug interactions, such as CYP2C19 with proton pump inhibitors and TPMT with thiopurines, building on the foundational principles of personalized medicine learned throughout the PharmD program.
1. Which cytochrome P450 enzyme is primarily responsible for the metabolism of many proton pump inhibitors (PPIs), such as omeprazole and lansoprazole?
- a. CYP3A4
- b. CYP1A2
- c. CYP2D6
- d. CYP2C19
Answer: d. CYP2C19
2. A patient with a CYP2C19 poor metabolizer (PM) phenotype is prescribed a standard dose of omeprazole. Compared to a normal metabolizer, this patient will likely have:
- a. Lower plasma concentrations of omeprazole and reduced efficacy.
- b. Higher plasma concentrations of omeprazole and increased efficacy.
- c. No difference in plasma concentration or efficacy.
- d. Faster conversion of omeprazole to its active form.
Answer: b. Higher plasma concentrations of omeprazole and increased efficacy.
3. In the context of H. pylori eradication, which CYP2C19 phenotype is most associated with treatment failure when using a standard PPI-based triple therapy regimen?
- a. Poor Metabolizer (PM)
- b. Intermediate Metabolizer (IM)
- c. Normal Metabolizer (NM)
- d. Ultra-rapid Metabolizer (UM)
Answer: d. Ultra-rapid Metabolizer (UM)
4. The Clinical Pharmacogenetics Implementation Consortium (CPIC) provides guidelines that help clinicians:
- a. Diagnose genetic disorders.
- b. Determine if a patient needs genetic testing.
- c. Understand how to use available genetic test results to optimize drug therapy.
- d. Set pricing for genetic tests.
Answer: c. Understand how to use available genetic test results to optimize drug therapy.
5. Thiopurine medications, such as azathioprine, are used for inflammatory bowel disease (a GI disorder). Patients with a deficiency in which enzyme are at high risk for life-threatening myelosuppression?
- a. CYP2C19
- b. Thiopurine S-methyltransferase (TPMT)
- c. UDP-glucuronosyltransferase (UGT)
- d. Dihydropyrimidine dehydrogenase (DPD)
Answer: b. Thiopurine S-methyltransferase (TPMT)
6. What does the term “genotype” refer to?
- a. The observable characteristics of an individual.
- b. The specific genetic makeup or set of alleles for a particular gene.
- c. A drug’s mechanism of action.
- d. The rate at which a drug is metabolized.
Answer: b. The specific genetic makeup or set of alleles for a particular gene.
7. A patient’s predicted metabolic status based on their genotype (e.g., “Poor Metabolizer”) is referred to as their:
- a. Phenotype
- b. Karyotype
- c. Haplotype
- d. Somatype
Answer: a. Phenotype
8. According to CPIC guidelines, if a patient is a known CYP2C19 ultra-rapid metabolizer being treated for H. pylori, what is the recommended action regarding their PPI therapy?
- a. Use half the standard dose.
- b. No change in dose is needed.
- c. Increase the PPI dose by 100% or consider an H2RA.
- d. Discontinue the PPI and use antacids only.
Answer: c. Increase the PPI dose by 100% or consider an H2RA.
9. Which of the following is a key resource a pharmacist can use to find information on gene-drug interactions and dosing guidelines?
- a. Wikipedia
- b. The P&T committee minutes from a local hospital.
- c. The PharmGKB (Pharmacogenomics Knowledgebase) database.
- d. A general Google search.
Answer: c. The PharmGKB (Pharmacogenomics Knowledgebase) database.
10. The nomenclature CYP2C19*1/*1 most likely corresponds to which phenotype?*
- a. Poor Metabolizer
- b. Intermediate Metabolizer
- c. Normal (Extensive) Metabolizer
- d. Ultra-rapid Metabolizer
Answer: c. Normal (Extensive) Metabolizer
11. The topic “Pharmacogenomics for Gastrointestinal Disorders” is a specific module in the Patient Care 4 course.
- a. True
- b. False
Answer: a. True
12. The interaction between omeprazole and clopidogrel is significant because both drugs are metabolized by CYP2C19. Omeprazole can inhibit the conversion of clopidogrel (a prodrug) to its active form. This is an example of:
- a. A pharmacodynamic interaction.
- b. A pharmacokinetic, gene-drug interaction.
- c. A chelation interaction.
- d. A food-drug interaction.
Answer: b. A pharmacokinetic, gene-drug interaction.
13. A “single nucleotide polymorphism” (SNP) is:
- a. A variation in a single base pair in a DNA sequence.
- b. A large chromosomal abnormality.
- c. The complete absence of a gene.
- d. A type of protein.
Answer: a. A variation in a single base pair in a DNA sequence.
**14. A patient with inflammatory bowel disease is found to be homozygous for a non-functional TPMT allele (e.g., 3A/3A). If started on a standard dose of azathioprine, they are at an extremely high risk of:
- a. Treatment failure
- b. Severe nausea and vomiting
- c. Life-threatening bone marrow suppression
- d. Kidney failure
Answer: c. Life-threatening bone marrow suppression
15. A star (*) allele designation, such as CYP2C19*2, is used to define a specific:
- a. Drug class
- b. Haplotype or variant allele
- c. Disease state
- d. Brand name of a genetic test
Answer: b. Haplotype or variant allele
16. The pharmacogenomics of drug-metabolizing enzymes is a foundational topic for understanding PGx in GI disorders.
- a. True
- b. False
Answer: a. True
17. The efficacy of the 5-HT3 antagonist ondansetron, used for nausea, can be affected by polymorphisms in which gene?
- a. TPMT
- b. CYP2C19
- c. CYP2D6
- d. SLCO1B1
Answer: c. CYP2D6
18. A CYP2C19 ultra-rapid metabolizer might require a higher dose of a PPI for GERD symptoms because:
- a. They clear the drug from their system so quickly that standard doses may not provide adequate acid suppression.
- b. They have more proton pumps in their stomach.
- c. They are less sensitive to the drug’s effects.
- d. They absorb the drug more slowly.
Answer: a. They clear the drug from their system so quickly that standard doses may not provide adequate acid suppression.
19. The purpose of CPIC guidelines is to advise clinicians on:
- a. Whether to order a genetic test.
- b. How to interpret a genetic test result to guide prescribing.
- c. The pathophysiology of genetic diseases.
- d. The cost-effectiveness of genetic testing.
Answer: b. How to interpret a genetic test result to guide prescribing.
20. A patient’s genotype is CYP2C19*1/*17. The 17 allele is a gain-of-function allele. This patient would likely be classified as what kind of metabolizer?
- a. Poor Metabolizer
- b. Intermediate Metabolizer
- c. Normal Metabolizer
- d. Rapid or Ultra-rapid Metabolizer
Answer: d. Rapid or Ultra-rapid Metabolizer
21. Considering the role of genetics as a determinant of drug metabolism is a key course objective in Medicinal Chemistry.
- a. True
- b. False
Answer: a. True
22. Which of the following PPIs is thought to be less affected by CYP2C19 polymorphisms compared to omeprazole?
- a. Lansoprazole
- b. Esomeprazole
- c. Rabeprazole
- d. Pantoprazole
Answer: c. Rabeprazole
23. Pre-emptive genotyping for TPMT is recommended before initiating which class of GI drugs?
- a. Proton pump inhibitors
- b. H2-receptor antagonists
- c. Thiopurines (azathioprine, 6-mercaptopurine)
- d. 5-HT3 antagonists
Answer: c. Thiopurines (azathioprine, 6-mercaptopurine)
24. Which of the following is an example of a no-function allele for CYP2C19?
- a. CYP2C19*1
- b. CYP2C19*17
- c. CYP2C19*2
- d. All of the above are functional.
Answer: c. CYP2C19*2
25. A pharmacist’s role in GI pharmacogenomics includes:
- a. Recommending appropriate genetic testing.
- b. Interpreting test results to make dosing recommendations.
- c. Educating patients and providers about gene-drug interactions.
- d. All of the above.
Answer: d. All of the above.
26. The term “pharmacogenetics” typically refers to the study of:
- a. How the entire genome influences drug response.
- b. How single genes or a few genes influence drug response.
- c. The genetic basis of disease.
- d. The use of gene therapy to treat diseases.
Answer: b. How single genes or a few genes influence drug response.
27. In a patient who is a CYP2D6 ultra-rapid metabolizer, standard doses of ondansetron may result in:
- a. Increased risk of side effects like QTc prolongation.
- b. No change in clinical effect.
- c. Decreased efficacy and poor control of nausea/vomiting.
- d. A severe allergic reaction.
Answer: c. Decreased efficacy and poor control of nausea/vomiting.
28. Why is pharmacogenomic testing not routinely done for all drugs?
- a. The evidence linking genetic variation to clinical outcomes is not always strong.
- b. The cost of testing can be a barrier.
- c. Clinical guidelines for acting on the results are not always available.
- d. All of the above.
Answer: d. All of the above.
29. The concept of “personalized medicine” involves using information about a person’s genes, proteins, and environment to prevent, diagnose, and treat disease.
- a. True
- b. False
Answer: a. True
30. Which of the following is a potential advantage of PGx-guided PPI therapy?
- a. Increased rates of H. pylori eradication in all patients.
- b. Faster symptom relief in GERD for patients with certain genotypes.
- c. A more cost-effective approach by avoiding trial-and-error prescribing.
- d. All of the above.
Answer: d. All of the above.
31. The TPMT gene codes for an enzyme involved in what type of metabolic reaction?
- a. Oxidation
- b. Hydrolysis
- c. Methylation
- d. Reduction
Answer: c. Methylation
32. For a CYP2C19 poor metabolizer, which of the following statements is true regarding their ability to heal from erosive esophagitis with a standard PPI dose?
- a. They will likely have higher healing rates than normal metabolizers.
- b. They will likely have lower healing rates than normal metabolizers.
- c. Their healing rates will be the same as normal metabolizers.
- d. They cannot take PPIs.
Answer: a. They will likely have higher healing rates than normal metabolizers.
33. What is the pharmacist’s best first step when a genetic test result is received for a patient?
- a. Immediately change all of the patient’s medications.
- b. Consult a reliable resource like CPIC guidelines or PharmGKB.
- c. Call the patient and explain the results in technical terms.
- d. File the report in the chart without review.
Answer: b. Consult a reliable resource like CPIC guidelines or PharmGKB.
34. The understanding of how genetics contributes to variability in drug metabolism is a key objective in the Principles of Drug Therapy Individualization course.
- a. True
- b. False
Answer: a. True
35. A patient’s genotype is reported as “heterozygous” for a non-functional allele. This means they have:
- a. Two normal, functional alleles.
- b. Two non-functional alleles.
- c. One normal, functional allele and one non-functional allele.
- d. One gain-of-function allele.
Answer: c. One normal, functional allele and one non-functional allele.
36. A patient who is a TPMT poor metabolizer should receive what percentage of the standard starting dose of azathioprine?
- a. 100% of the standard dose.
- b. 200% of the standard dose.
- c. 50% of the standard dose.
- d. Around 10% of the standard dose, or the drug should be avoided.
Answer: d. Around 10% of the standard dose, or the drug should be avoided.
37. Which PPI is considered a weak inhibitor of CYP2C19, making it a potentially preferred agent in patients taking clopidogrel?
- a. Omeprazole
- b. Esomeprazole
- c. Pantoprazole
- d. Lansoprazole
Answer: c. Pantoprazole
38. The field of pharmacogenomics focuses exclusively on drug metabolism.
- a. True
- b. False
Answer: b. False
39. A “diplotype” refers to:
- a. The brand name of a genetic test.
- b. The pair of alleles that make up a genotype (one from each chromosome).
- c. A specific type of SNP.
- d. The clinical recommendation based on a genotype.
Answer: b. The pair of alleles that make up a genotype (one from each chromosome).
40. For which GI medication class is the clinical utility of pharmacogenomic testing most established and recommended by guidelines?
- a. H2-receptor antagonists
- b. Thiopurines
- c. Antacids
- d. Stool softeners
Answer: b. Thiopurines
41. Which factor can influence a patient’s phenotype besides their genotype?
- a. The patient’s hair color.
- b. Concomitant medications that inhibit or induce enzymes.
- c. The time of day.
- d. The patient’s blood type.
Answer: b. Concomitant medications that inhibit or induce enzymes.
42. Which of the following is the “wild-type” or normal function allele for most CYP enzymes?
- a. 1
- b. 2
- c. 3
- d. 17
Answer: a. 1
43. A patient’s PGx test shows they are a CYP2C19 poor metabolizer. This genetic information:
- a. Will change over their lifetime.
- b. Is only relevant for one year.
- c. Will not change and is relevant for any future therapy with CYP2C19 substrates.
- d. Is only important if they have GERD.
Answer: c. Will not change and is relevant for any future therapy with CYP2C19 substrates.
44. The primary goal of using pharmacogenomics in GI and other disorders is to:
- a. Increase the cost of healthcare.
- b. Move from a “one-size-fits-all” approach to an individualized approach to pharmacotherapy.
- c. Replace all existing drugs with new ones.
- d. Eliminate the need for pharmacists.
Answer: b. Move from a “one-size-fits-all” approach to an individualized approach to pharmacotherapy.
45. Which of the following is a GI-related adverse effect where PGx can play a role in prevention?
- a. Diarrhea caused by irinotecan (related to UGT1A1).
- b. Constipation caused by opioids.
- c. Nausea caused by metformin.
- d. All of the above.
Answer: a. Diarrhea caused by irinotecan (related to UGT1A1).
46. When counseling a patient on their PGx results, it’s important for the pharmacist to:
- a. Use highly technical language to demonstrate expertise.
- b. Explain the results clearly and what they mean for their specific medication therapy.
- c. Guarantee that they will never have a side effect.
- d. Tell them their genes are “bad”.
Answer: b. Explain the results clearly and what they mean for their specific medication therapy.
47. The NUDT15 gene is particularly important for predicting thiopurine toxicity in which patient populations?
- a. European
- b. African
- c. Asian and Hispanic
- d. All populations equally.
Answer: c. Asian and Hispanic
48. An active learning session on pharmacogenomics for GI disorders is part of the Patient Care 4 curriculum.
- a. True
- b. False
Answer: a. True
49. If a patient is a CYP2C19 UM and fails H. pylori therapy with a standard dose of lansoprazole, the failure is likely due to:
- a. Bacterial resistance to the antibiotics.
- b. Inadequate acid suppression from the PPI, allowing the antibiotics to be less effective.
- c. Patient non-adherence.
- d. Both a and b could be contributing factors.
Answer: d. Both a and b could be contributing factors.
50. The future of GI medication management will likely involve:
- a. Less involvement from pharmacists.
- b. The complete elimination of PPIs.
- c. More routine, pre-emptive use of pharmacogenomic testing to guide initial drug selection and dosing.
- d. A return to using only H2-receptor antagonists.
Answer: c. More routine, pre-emptive use of pharmacogenomic testing to guide initial drug selection and dosing.