DAVIS'S DRUG GUIDE FOR NURSES
19TH EDITION
• AUTHOR(S)APRIL HAZARD
VALLERAND; CYNTHIA SANOSKI
TEST BANK
1)
Drug Reference: Warfarin — Vitamin K Antagonist — Drug
Interactions & Detecting and Managing Adverse Drug Reactions
Stem: A 72-year-old man with atrial fibrillation is on warfarin 5
mg PO nightly. He was started 3 days ago on trimethoprim-
sulfamethoxazole (TMP-SMX) for a UTI. His INR yesterday was
2.4. Today he reports new bruising and his INR is 4.6. Which
nursing action is the most appropriate now?
A. Hold warfarin and contact the prescriber immediately.
B. Encourage the patient to eat more leafy greens to lower the
INR.
C. Give oral vitamin K 10 mg now without contacting the
,prescriber.
D. Continue warfarin and recheck INR in 3 days.
Correct Answer: A
Rationale — Correct (A): Holding warfarin and contacting the
prescriber is the safest immediate nursing action when INR is
supratherapeutic with bleeding/bruising. TMP-SMX can
potentiate warfarin effect via CYP interaction and reduced
vitamin K–producing gut flora. Prompt prescriber notification
allows a tailored reversal/monitoring plan.
Rationales — Incorrect:
B. Increasing leafy greens is not immediate management —
dietary change is slow and unreliable for acute
supratherapeutic INR and may confuse care.
C. Administering 10 mg vitamin K without prescriber orders may
overcorrect and carries risk; nurse should consult prescriber for
dose and route.
D. Continuing warfarin with INR 4.6 and bleeding is unsafe;
delay risks major hemorrhage.
Teaching Point: Hold warfarin and notify provider for
supratherapeutic INR with bleeding.
Citation: Vallerand, A. H., & Sanoski, C. (2025). Davis's Drug
Guide for Nurses (19th ed.). [Warfarin — Drug Interactions &
Detecting and Managing Adverse Drug Reactions].
2)
,Drug Reference: Codeine — Opioid Analgesic (prodrug) —
Pharmacogenomics & Patient/Family Teaching
Stem: A 9-year-old child was prescribed codeine after a
tonsillectomy. The parent asks whether codeine will work the
same for all children. Which reply best reflects evidence-based
pharmacogenomic nursing teaching?
A. “Yes — codeine acts the same in everyone; no need to
worry.”
B. “Some children cannot convert codeine to its active form;
we’ll ask the prescriber for a safer option.”
C. “If the child seems sleepy, give a double dose next time so
they feel pain relief.”
D. “Give honey with codeine to boost metabolism and improve
effect.”
Correct Answer: B
Rationale — Correct (B): Codeine’s analgesic effect requires
CYP2D6-mediated conversion to morphine. Some children are
poor metabolizers (little effect) and some are ultrarapid
metabolizers (risk of toxicity). For post-tonsillectomy pediatric
patients, alternatives to codeine are preferred; nurse should
communicate pharmacogenomic concerns to prescriber and
caregivers.
Rationales — Incorrect:
A. Incorrect — codeine response varies by CYP2D6 genotype.
C. Doubling dose is dangerous and may cause respiratory
, depression, especially in ultrarapid metabolizers.
D. No evidence supports using honey to affect CYP2D6
conversions; this is unsafe advice.
Teaching Point: Codeine efficacy and safety depend on CYP2D6
genotype — avoid in many children.
Citation: Vallerand, A. H., & Sanoski, C. (2025). Davis's Drug
Guide for Nurses (19th ed.). [Codeine — Pharmacogenomics &
Patient/Family Teaching].
3)
Drug Reference: Isotretinoin (Accutane) — Retinoid —
Overview of REMS & Females of Reproductive Potential
Stem: A 22-year-old female with severe acne is being
considered for isotretinoin. She is sexually active and not using
contraception. Which nursing action is the highest priority
before dispensing isotretinoin?
A. Provide written instructions on sun protection.
B. Confirm negative pregnancy test and verify enrollment in
REMS (iPLEDGE).
C. Teach to take isotretinoin with a high-fat meal to increase
absorption.
D. Advise avoidance of alcohol while taking isotretinoin.
Correct Answer: B
19TH EDITION
• AUTHOR(S)APRIL HAZARD
VALLERAND; CYNTHIA SANOSKI
TEST BANK
1)
Drug Reference: Warfarin — Vitamin K Antagonist — Drug
Interactions & Detecting and Managing Adverse Drug Reactions
Stem: A 72-year-old man with atrial fibrillation is on warfarin 5
mg PO nightly. He was started 3 days ago on trimethoprim-
sulfamethoxazole (TMP-SMX) for a UTI. His INR yesterday was
2.4. Today he reports new bruising and his INR is 4.6. Which
nursing action is the most appropriate now?
A. Hold warfarin and contact the prescriber immediately.
B. Encourage the patient to eat more leafy greens to lower the
INR.
C. Give oral vitamin K 10 mg now without contacting the
,prescriber.
D. Continue warfarin and recheck INR in 3 days.
Correct Answer: A
Rationale — Correct (A): Holding warfarin and contacting the
prescriber is the safest immediate nursing action when INR is
supratherapeutic with bleeding/bruising. TMP-SMX can
potentiate warfarin effect via CYP interaction and reduced
vitamin K–producing gut flora. Prompt prescriber notification
allows a tailored reversal/monitoring plan.
Rationales — Incorrect:
B. Increasing leafy greens is not immediate management —
dietary change is slow and unreliable for acute
supratherapeutic INR and may confuse care.
C. Administering 10 mg vitamin K without prescriber orders may
overcorrect and carries risk; nurse should consult prescriber for
dose and route.
D. Continuing warfarin with INR 4.6 and bleeding is unsafe;
delay risks major hemorrhage.
Teaching Point: Hold warfarin and notify provider for
supratherapeutic INR with bleeding.
Citation: Vallerand, A. H., & Sanoski, C. (2025). Davis's Drug
Guide for Nurses (19th ed.). [Warfarin — Drug Interactions &
Detecting and Managing Adverse Drug Reactions].
2)
,Drug Reference: Codeine — Opioid Analgesic (prodrug) —
Pharmacogenomics & Patient/Family Teaching
Stem: A 9-year-old child was prescribed codeine after a
tonsillectomy. The parent asks whether codeine will work the
same for all children. Which reply best reflects evidence-based
pharmacogenomic nursing teaching?
A. “Yes — codeine acts the same in everyone; no need to
worry.”
B. “Some children cannot convert codeine to its active form;
we’ll ask the prescriber for a safer option.”
C. “If the child seems sleepy, give a double dose next time so
they feel pain relief.”
D. “Give honey with codeine to boost metabolism and improve
effect.”
Correct Answer: B
Rationale — Correct (B): Codeine’s analgesic effect requires
CYP2D6-mediated conversion to morphine. Some children are
poor metabolizers (little effect) and some are ultrarapid
metabolizers (risk of toxicity). For post-tonsillectomy pediatric
patients, alternatives to codeine are preferred; nurse should
communicate pharmacogenomic concerns to prescriber and
caregivers.
Rationales — Incorrect:
A. Incorrect — codeine response varies by CYP2D6 genotype.
C. Doubling dose is dangerous and may cause respiratory
, depression, especially in ultrarapid metabolizers.
D. No evidence supports using honey to affect CYP2D6
conversions; this is unsafe advice.
Teaching Point: Codeine efficacy and safety depend on CYP2D6
genotype — avoid in many children.
Citation: Vallerand, A. H., & Sanoski, C. (2025). Davis's Drug
Guide for Nurses (19th ed.). [Codeine — Pharmacogenomics &
Patient/Family Teaching].
3)
Drug Reference: Isotretinoin (Accutane) — Retinoid —
Overview of REMS & Females of Reproductive Potential
Stem: A 22-year-old female with severe acne is being
considered for isotretinoin. She is sexually active and not using
contraception. Which nursing action is the highest priority
before dispensing isotretinoin?
A. Provide written instructions on sun protection.
B. Confirm negative pregnancy test and verify enrollment in
REMS (iPLEDGE).
C. Teach to take isotretinoin with a high-fat meal to increase
absorption.
D. Advise avoidance of alcohol while taking isotretinoin.
Correct Answer: B
