DAVIS'S DRUG GUIDE FOR NURSES
19TH EDITION
• AUTHOR(S)APRIL HAZARD
VALLERAND; CYNTHIA SANOSKI
TEST BANK
1
Drug Reference
Warfarin — Vitamin K Antagonist — Pharmacogenomics; Drug
Interactions; Detecting and Managing Adverse Drug Reactions
Stem
A 68-year-old man with new atrial fibrillation is prescribed
warfarin 5 mg PO nightly. Current meds: amiodarone started 2
days ago, lab results: INR 2.6 (yesterday), baseline ALT normal,
no bleeding. Which nursing action is most appropriate before
administering tonight’s dose?
A. Administer the warfarin as ordered and schedule INR recheck
in 7 days.
B. Hold warfarin and notify prescriber about recent amiodarone
,initiation and trending INR.
C. Give half the dose (2.5 mg) now and repeat INR in 24 hours.
D. Give full dose and teach patient to avoid leafy greens.
Correct Answer: B
Rationale — Correct (B)
Amiodarone inhibits warfarin metabolism and can increase INR
and bleeding risk; initiation requires dose reassessment and
closer INR monitoring. Holding and notifying prescriber is the
safest immediate action to prevent supratherapeutic
anticoagulation while assessment and order clarification occur.
Rationales — Incorrect
A. Administering without addressing the drug interaction risks
bleeding; waiting 7 days is unsafe after starting amiodarone.
C. Arbitrary halving of dose is not an evidence-based mitigation
without prescriber order or INR trend guidance.
D. Patient teaching about diet is useful but not the priority—
drug interaction management is immediate.
Teaching Point: Amiodarone increases warfarin effect; notify
prescriber and check INR frequently.
Citation: Vallerand, A. H., & Sanoski, C. (2025). Davis's Drug
Guide for Nurses (19th ed.). [Warfarin section].
2
,Drug Reference
Clopidogrel — P2Y₁₂ ADP Receptor Antagonist —
Pharmacogenomics; Drug Interactions; Patient/Family Teaching
Stem
A 55-year-old woman post-PCI is prescribed clopidogrel 75 mg
daily. Her history shows she is a poor CYP2C19 metabolizer on
prior pharmacogenomic testing. Which nursing intervention is
most appropriate?
A. Proceed with clopidogrel and reinforce adherence teaching.
B. Hold clopidogrel and obtain a provider order for an
alternative antiplatelet.
C. Double the clopidogrel dose to overcome reduced
metabolism.
D. Add aspirin and continue clopidogrel as ordered.
Correct Answer: B
Rationale — Correct (B)
CYP2C19 poor metabolizers have reduced conversion of
clopidogrel to its active metabolite, lowering antiplatelet effect
and increasing thrombotic risk. Holding and prompting provider
review for an alternative (e.g., prasugrel or ticagrelor when
appropriate) aligns with pharmacogenomic safety principles.
Rationales — Incorrect
A. Continuing clopidogrel risks stent thrombosis in poor
metabolizers.
C. Doubling dose is not recommended—efficacy depends on
, activation, not simple dose increase.
D. Adding aspirin without addressing clopidogrel ineffectiveness
may still be insufficient and increases bleeding risk.
Teaching Point: CYP2C19 poor metabolizers may need
alternative antiplatelets.
Citation: Vallerand, A. H., & Sanoski, C. (2025). Davis's Drug
Guide for Nurses (19th ed.). [Clopidogrel section].
3
Drug Reference
Isotretinoin — Retinoid — REMS; Females of Reproductive
Potential; Patient/Family Teaching
Stem
A 20-year-old woman with severe acne is enrolled in an
isotretinoin REMS program and brings her pharmacy packet to
the clinic. She reports she is sexually active and uses condoms
occasionally. Which statement by the nurse indicates the
priority teaching point before dispensing?
A. “Continue current contraception and you can stop if you miss
two doses.”
B. “You must use two forms of effective contraception and
complete regular pregnancy testing.”
C. “One reliable contraceptive method is sufficient while on
isotretinoin.”
19TH EDITION
• AUTHOR(S)APRIL HAZARD
VALLERAND; CYNTHIA SANOSKI
TEST BANK
1
Drug Reference
Warfarin — Vitamin K Antagonist — Pharmacogenomics; Drug
Interactions; Detecting and Managing Adverse Drug Reactions
Stem
A 68-year-old man with new atrial fibrillation is prescribed
warfarin 5 mg PO nightly. Current meds: amiodarone started 2
days ago, lab results: INR 2.6 (yesterday), baseline ALT normal,
no bleeding. Which nursing action is most appropriate before
administering tonight’s dose?
A. Administer the warfarin as ordered and schedule INR recheck
in 7 days.
B. Hold warfarin and notify prescriber about recent amiodarone
,initiation and trending INR.
C. Give half the dose (2.5 mg) now and repeat INR in 24 hours.
D. Give full dose and teach patient to avoid leafy greens.
Correct Answer: B
Rationale — Correct (B)
Amiodarone inhibits warfarin metabolism and can increase INR
and bleeding risk; initiation requires dose reassessment and
closer INR monitoring. Holding and notifying prescriber is the
safest immediate action to prevent supratherapeutic
anticoagulation while assessment and order clarification occur.
Rationales — Incorrect
A. Administering without addressing the drug interaction risks
bleeding; waiting 7 days is unsafe after starting amiodarone.
C. Arbitrary halving of dose is not an evidence-based mitigation
without prescriber order or INR trend guidance.
D. Patient teaching about diet is useful but not the priority—
drug interaction management is immediate.
Teaching Point: Amiodarone increases warfarin effect; notify
prescriber and check INR frequently.
Citation: Vallerand, A. H., & Sanoski, C. (2025). Davis's Drug
Guide for Nurses (19th ed.). [Warfarin section].
2
,Drug Reference
Clopidogrel — P2Y₁₂ ADP Receptor Antagonist —
Pharmacogenomics; Drug Interactions; Patient/Family Teaching
Stem
A 55-year-old woman post-PCI is prescribed clopidogrel 75 mg
daily. Her history shows she is a poor CYP2C19 metabolizer on
prior pharmacogenomic testing. Which nursing intervention is
most appropriate?
A. Proceed with clopidogrel and reinforce adherence teaching.
B. Hold clopidogrel and obtain a provider order for an
alternative antiplatelet.
C. Double the clopidogrel dose to overcome reduced
metabolism.
D. Add aspirin and continue clopidogrel as ordered.
Correct Answer: B
Rationale — Correct (B)
CYP2C19 poor metabolizers have reduced conversion of
clopidogrel to its active metabolite, lowering antiplatelet effect
and increasing thrombotic risk. Holding and prompting provider
review for an alternative (e.g., prasugrel or ticagrelor when
appropriate) aligns with pharmacogenomic safety principles.
Rationales — Incorrect
A. Continuing clopidogrel risks stent thrombosis in poor
metabolizers.
C. Doubling dose is not recommended—efficacy depends on
, activation, not simple dose increase.
D. Adding aspirin without addressing clopidogrel ineffectiveness
may still be insufficient and increases bleeding risk.
Teaching Point: CYP2C19 poor metabolizers may need
alternative antiplatelets.
Citation: Vallerand, A. H., & Sanoski, C. (2025). Davis's Drug
Guide for Nurses (19th ed.). [Clopidogrel section].
3
Drug Reference
Isotretinoin — Retinoid — REMS; Females of Reproductive
Potential; Patient/Family Teaching
Stem
A 20-year-old woman with severe acne is enrolled in an
isotretinoin REMS program and brings her pharmacy packet to
the clinic. She reports she is sexually active and uses condoms
occasionally. Which statement by the nurse indicates the
priority teaching point before dispensing?
A. “Continue current contraception and you can stop if you miss
two doses.”
B. “You must use two forms of effective contraception and
complete regular pregnancy testing.”
C. “One reliable contraceptive method is sufficient while on
isotretinoin.”
