DAVIS'S DRUG GUIDE FOR NURSES
19TH EDITION
• AUTHOR(S)APRIL HAZARD
VALLERAND; CYNTHIA SANOSKI
TEST BANK
1
Drug Reference — Warfarin (generic) — Vitamin K antagonist
— Pharmacogenomics & Drug Interactions (Nursing
Implications, Patient/Family Teaching)
Stem: A 68-year-old woman with atrial fibrillation is to start
warfarin 5 mg PO nightly. Her baseline INR is 1.1. She is taking
amiodarone for ventricular ectopy and reports a history of slow
wound healing. Which action should the nurse perform before
administering the first dose?
A. Administer warfarin and obtain INR in 3 days.
B. Hold warfarin and notify the prescriber to consider a lower
starting dose.
C. Administer warfarin and increase vitamin K dietary intake to
,reduce bleeding risk.
D. Hold warfarin and schedule a daily aPTT to monitor
anticoagulation.
Correct Answer: B
Rationale — Correct: Amiodarone inhibits warfarin metabolism
(CYP interactions) increasing bleeding risk; pharmacogenomic
variants (CYP2C9/VKORC1) and drug interactions favor starting
at a lower dose or obtaining prescriber input. Holding and
notifying prescriber to lower the dose prevents early over-
anticoagulation.
Rationales — Incorrect:
A. INR in 3 days may be too late if interaction causes over-
anticoagulation immediately. Risky.
C. Increasing dietary vitamin K without prescriber coordination
counteracts warfarin and is inappropriate.
D. aPTT monitors heparin, not warfarin; it’s not the correct test.
Teaching point: Check interacting drugs and consider lower
warfarin starting doses with CYP inhibitors.
Citation: Vallerand, A. H., & Sanoski, C. A. (2024). Davis's Drug
Guide for Nurses (19th ed.). [Warfarin —
Pharmacogenomics/Drug Interactions].
2
,Drug Reference — Clopidogrel (generic) — P2Y₁₂ ADP receptor
inhibitor — Pharmacogenomics (Patient/Family Teaching &
Nursing Implications)
Stem: A 52-year-old man post-PCI is prescribed clopidogrel 75
mg daily. He has a recent genotyping result showing a CYP2C19
loss-of-function allele. Which nursing action is most
appropriate?
A. Teach the patient to stop clopidogrel and use aspirin only.
B. Administer clopidogrel as ordered — genetic results do not
affect therapy.
C. Hold medication and notify the prescriber because
alternative antiplatelet therapy may be needed.
D. Double the clopidogrel dose to overcome reduced
metabolism.
Correct Answer: C
Rationale — Correct: CYP2C19 loss-of-function reduces
clopidogrel activation resulting in decreased antiplatelet effect
and higher ischemic risk; the nurse should hold/notify
prescriber so an alternative (e.g., prasugrel or ticagrelor) can be
considered per pharmacogenomic guidance.
Rationales — Incorrect:
A. Stopping without prescriber input risks stent thrombosis;
aspirin alone may be insufficient.
B. Ignoring genotype risks therapy failure.
, D. Doubling dose is not an evidence-based response and may
not restore effect; prescriber decision required.
Teaching point: CYP2C19 loss-of-function alleles may require
alternative antiplatelet agents.
Citation: Vallerand, A. H., & Sanoski, C. A. (2024). Davis's Drug
Guide for Nurses (19th ed.). [Clopidogrel —
Pharmacogenomics].
3
Drug Reference — Isotretinoin (Accutane, Absorica) —
Retinoid — REMS & Females of Reproductive Potential (Nursing
Implications, Patient/Family Teaching)
Stem: A 21-year-old woman with severe cystic acne is started
on isotretinoin. She tells the nurse she “might try” to get
pregnant in a few months. Which is the nurse’s priority action?
A. Provide isotretinoin and advise high-efficacy contraception is
optional.
B. Explain iPLEDGE/REMS requirements and confirm two forms
of contraception before dispensing.
C. Advise use of oral contraceptive only if a pelvic exam is
normal.
D. Tell the patient to use condoms and begin isotretinoin.
Correct Answer: B
19TH EDITION
• AUTHOR(S)APRIL HAZARD
VALLERAND; CYNTHIA SANOSKI
TEST BANK
1
Drug Reference — Warfarin (generic) — Vitamin K antagonist
— Pharmacogenomics & Drug Interactions (Nursing
Implications, Patient/Family Teaching)
Stem: A 68-year-old woman with atrial fibrillation is to start
warfarin 5 mg PO nightly. Her baseline INR is 1.1. She is taking
amiodarone for ventricular ectopy and reports a history of slow
wound healing. Which action should the nurse perform before
administering the first dose?
A. Administer warfarin and obtain INR in 3 days.
B. Hold warfarin and notify the prescriber to consider a lower
starting dose.
C. Administer warfarin and increase vitamin K dietary intake to
,reduce bleeding risk.
D. Hold warfarin and schedule a daily aPTT to monitor
anticoagulation.
Correct Answer: B
Rationale — Correct: Amiodarone inhibits warfarin metabolism
(CYP interactions) increasing bleeding risk; pharmacogenomic
variants (CYP2C9/VKORC1) and drug interactions favor starting
at a lower dose or obtaining prescriber input. Holding and
notifying prescriber to lower the dose prevents early over-
anticoagulation.
Rationales — Incorrect:
A. INR in 3 days may be too late if interaction causes over-
anticoagulation immediately. Risky.
C. Increasing dietary vitamin K without prescriber coordination
counteracts warfarin and is inappropriate.
D. aPTT monitors heparin, not warfarin; it’s not the correct test.
Teaching point: Check interacting drugs and consider lower
warfarin starting doses with CYP inhibitors.
Citation: Vallerand, A. H., & Sanoski, C. A. (2024). Davis's Drug
Guide for Nurses (19th ed.). [Warfarin —
Pharmacogenomics/Drug Interactions].
2
,Drug Reference — Clopidogrel (generic) — P2Y₁₂ ADP receptor
inhibitor — Pharmacogenomics (Patient/Family Teaching &
Nursing Implications)
Stem: A 52-year-old man post-PCI is prescribed clopidogrel 75
mg daily. He has a recent genotyping result showing a CYP2C19
loss-of-function allele. Which nursing action is most
appropriate?
A. Teach the patient to stop clopidogrel and use aspirin only.
B. Administer clopidogrel as ordered — genetic results do not
affect therapy.
C. Hold medication and notify the prescriber because
alternative antiplatelet therapy may be needed.
D. Double the clopidogrel dose to overcome reduced
metabolism.
Correct Answer: C
Rationale — Correct: CYP2C19 loss-of-function reduces
clopidogrel activation resulting in decreased antiplatelet effect
and higher ischemic risk; the nurse should hold/notify
prescriber so an alternative (e.g., prasugrel or ticagrelor) can be
considered per pharmacogenomic guidance.
Rationales — Incorrect:
A. Stopping without prescriber input risks stent thrombosis;
aspirin alone may be insufficient.
B. Ignoring genotype risks therapy failure.
, D. Doubling dose is not an evidence-based response and may
not restore effect; prescriber decision required.
Teaching point: CYP2C19 loss-of-function alleles may require
alternative antiplatelet agents.
Citation: Vallerand, A. H., & Sanoski, C. A. (2024). Davis's Drug
Guide for Nurses (19th ed.). [Clopidogrel —
Pharmacogenomics].
3
Drug Reference — Isotretinoin (Accutane, Absorica) —
Retinoid — REMS & Females of Reproductive Potential (Nursing
Implications, Patient/Family Teaching)
Stem: A 21-year-old woman with severe cystic acne is started
on isotretinoin. She tells the nurse she “might try” to get
pregnant in a few months. Which is the nurse’s priority action?
A. Provide isotretinoin and advise high-efficacy contraception is
optional.
B. Explain iPLEDGE/REMS requirements and confirm two forms
of contraception before dispensing.
C. Advise use of oral contraceptive only if a pelvic exam is
normal.
D. Tell the patient to use condoms and begin isotretinoin.
Correct Answer: B
