chap 8

Question 1

Genetic polymorphisms account for differences in metabolism, including:

1. Poor metabolizers, who lack a working enzyme
2. Intermediate metabolizers, who have one working, wild-type allele and one mutant allele
3. Extensive metabolizers, with two normally functioning alleles
4. All of the above

Answer 1

4. All of the above

Question 2

Up to 21% of Asians are ultra-rapid 2D6 metabolizers, leading to:

1. A need to monitor drugs metabolized by 2D6 for toxicity
2. Increased dosages needed of drugs metabolized by 2D6, such as the selective serotonin reuptake inhibitors
3. Decreased conversion of codeine to morphine by CYP 2D6
4. The need for lowered dosages of drugs, such as beta blockers

Answer 2

2. Increased dosages needed of drugs metabolized by 2D6, such as the selective serotonin reuptake inhibitors

Question 3

Rifampin is a nonspecific CYP450 inducer that may:

1. Lead to toxic levels of rifampin and must be monitored closely
2. Cause toxic levels of drugs, such as oral contraceptives, when coadministered
3. Induce the metabolism of drugs, such as oral contraceptives, leading to therapeutic failure
4. Cause nonspecific changes in drug metabolism

Answer 3

3. Induce the metabolism of drugs, such as oral contraceptives, leading to therapeutic failure

Question 4

Inhibition of P-glycoprotein by a drug such as quinidine may lead to:

1. Decreased therapeutic levels of quinidine
2. Increased therapeutic levels of quinidine
3. Decreased levels of a coadministered drug, such as digoxin, that requires P-glycoprotein for absorption and elimination
4. Increased levels of a coadministered drug, such as digoxin, that requires P-glycoprotein for absorption and elimination

Answer 4

4. Increased levels of a coadministered drug, such as digoxin, that requires P-glycoprotein for absorption and elimination

Question 5

Genetic testing for VCORC1 mutation to assess potential warfarin resistance is required prior to prescribing warfarin.

1. True
2. False

Answer 5

2. false

Question 6

Pharmacogenetic testing is required by the U.S. Food and Drug Administration prior to prescribing:

1. Erythromycin
2. Digoxin
3. Cetuximab
4. Rifampin

Answer 6

3. Cetuximab

Question 7

Carbamazepine has a Black Box Warning recommending testing for the HLA-B*1502 allele in patients with Asian ancestry prior to starting therapy due to:

1. Decreased effectiveness of carbamazepine in treating seizures in Asian patients with the HLA-B*1502 allele
2. Increased risk for drug interactions in Asian patients with the HLA-B*1502 allele
3. Increased risk for Stevens-Johnson syndrome in Asian patients with HLA-B*1502 allele
4. Patients who have the HLA-B*1502 allele being more likely to have a resistance to carbamazepine

Answer 7

3. Increased risk for Stevens-Johnson syndrome in Asian patients with HLA-B*1502 allele

Question 8

A genetic variation in how the metabolite of the cancer drug irinotecan SN-38 is inactivated by the body may lead to:

1. Decreased effectiveness of irinotecan in the treatment of cancer
2. Increased adverse drug reactions, such as neutropenia
3. Delayed metabolism of the prodrug irinotecan into the active metabolite SN-38
4. Increased concerns for irinotecan being carcinogenic

Answer 8

2. Increased adverse drug reactions, such as neutropenia

Question 9

Patients who have a poor metabolism phenotype will have:

1. Slowed metabolism of a prodrug into an active drug, leading to accumulation of prodrug
2. Accumulation of inactive metabolites of drugs
3. A need for increased dosages of medications
4. Increased elimination of an active drug

Answer 9

1. Slowed metabolism of a prodrug into an active drug, leading to accumulation of prodrug

Question 10

Ultra-rapid metabolizers of drugs may have:

1. To have dosages of drugs adjusted downward to prevent drug accumulation
2. Active drug rapidly metabolized into inactive metabolites, leading to potential therapeutic failure
3. Increased elimination of active, nonmetabolized drug
4. Slowed metabolism of a prodrug into an active drug, leading to an accumulation of prodrug

Answer 10

2. Active drug rapidly metabolized into inactive metabolites, leading to potential therapeutic failure

Question 11

A provider may consider testing for CYP2D6 variants prior to starting tamoxifen for breast cancer to:

1. Ensure the patient will not have increased adverse drug reactions to the tamoxifen
2. Identify potential drug-drug interactions that may occur with tamoxifen
3. Reduce the likelihood of therapeutic failure with tamoxifen treatment
4. Identify poor metabolizers of tamoxifen

Answer 11

3. Reduce the likelihood of therapeutic failure with tamoxifen treatment