DAVIS'S DRUG GUIDE FOR NURSES
19TH EDITION
• AUTHOR(S)APRIL HAZARD
VALLERAND; CYNTHIA SANOSKI
TEST BANK
1) Codeine — Opioid analgesic — Pharmacogenomics (Nursing
Implications & Patient/Family Teaching)
Stem: A 16-year-old female is admitted after a tonsillectomy
with an order for oral codeine for pain. Her oxygen saturation is
92% on room air and the nurse notes shallow respirations. The
chart contains no pharmacogenomic testing results. Which
action should the nurse take?
A. Administer the first dose as ordered and reassess respirations
in 15 minutes.
B. Hold the codeine, institute supplemental oxygen, and notify
the prescriber about possible ultrarapid CYP2D6 metabolism
risk.
C. Give half the ordered dose of codeine and document the
reduced dose.
,D. Substitute oral acetaminophen without notifying the
prescriber because nonopioid analgesia is safer.
Correct answer: B
Rationale — Correct (B):
Codeine is a prodrug metabolized by CYP2D6 to morphine;
patients who are ultrarapid metabolizers can develop life-
threatening respiratory depression. Given shallow respirations
and low O₂ saturation, holding the opioid, supporting
oxygenation, and notifying the prescriber (and flagging
pharmacogenomic risk) is the safest action. Davis highlights
pharmacogenomic variability (CYP2D6) and the need to
avoid/suspend opioids when respiratory compromise is present.
Rationale — Incorrect:
A. Administering when the patient already shows
hypoventilation risks worsening respiratory depression;
reassessment after giving an opioid is unsafe.
C. Arbitrary dose reduction without prescriber/MD order and
without addressing oxygenation still risks harm and doesn’t
address metabolic variability.
D. Substituting without prescriber notification is a medication-
use delegation error and may not provide adequate pain control
immediately.
Teaching point: Hold opioids for respiratory compromise and
consider CYP2D6 phenotype.
Citation (APA): Vallerand, A. H., & Sanoski, C. A. (2025). Davis's
Drug Guide for Nurses (19th ed.). [Pharmacogenomics].
,2) Clopidogrel — Antiplatelet (P2Y12 inhibitor) — The
Cytochrome P450 System & Drug Interactions (Nursing
Implications)
Stem: A patient with a recent coronary stent is taking
clopidogrel. The provider prescribes omeprazole for reflux.
Which nursing action is most appropriate before administering
both medications?
A. Administer both agents as ordered; document both in the
MAR.
B. Hold clopidogrel and notify the prescriber immediately to
request discontinuation.
C. Recognize potential CYP2C19 inhibition by omeprazole,
withhold omeprazole if possible, and discuss alternative PPI (or
H2 blocker) with prescriber.
D. Give clopidogrel with a high-fat meal to increase absorption
and add omeprazole at bedtime.
Correct answer: C
Rationale — Correct (C):
Clopidogrel is a CYP2C19-activated prodrug; potent CYP2C19
inhibitors (omeprazole) can reduce activation and antiplatelet
effect, increasing thrombosis risk. The nurse should identify the
interaction, withhold/avoid starting omeprazole if feasible, and
consult the prescriber for an alternative — this matches safe
medication-use guidance on CYP interactions.
, Rationale — Incorrect:
A. Co-administration without review risks clinically significant
loss of clopidogrel efficacy.
B. Holding clopidogrel without prescriber input endangers the
patient with stent thrombosis.
D. Food manipulation won’t overcome the metabolic
interaction and is irrelevant to CYP2C19 inhibition.
Teaching point: Check CYP450 interactions before adding PPIs
with prodrugs like clopidogrel.
Citation (APA): Vallerand, A. H., & Sanoski, C. A. (2025). Davis's
Drug Guide for Nurses (19th ed.). [The Cytochrome P450
System; Drug Interactions].
3) Isotretinoin — Retinoid (teratogen) — Overview of REMS &
Females of Reproductive Potential (Patient/Family Teaching;
Nursing Implications)
Stem: A 22-year-old woman is admitted for isotretinoin therapy
and reports inconsistent contraception. A pregnancy test in
triage is positive. Which is the nurse’s best action?
A. Proceed with the first dose because isotretinoin is most
teratogenic only during the first trimester.
B. Hold the medication, notify the prescriber, and follow REMS
enrollment/pregnancy-prevention program requirements.
C. Administer as ordered and provide contraception counseling
at discharge.
19TH EDITION
• AUTHOR(S)APRIL HAZARD
VALLERAND; CYNTHIA SANOSKI
TEST BANK
1) Codeine — Opioid analgesic — Pharmacogenomics (Nursing
Implications & Patient/Family Teaching)
Stem: A 16-year-old female is admitted after a tonsillectomy
with an order for oral codeine for pain. Her oxygen saturation is
92% on room air and the nurse notes shallow respirations. The
chart contains no pharmacogenomic testing results. Which
action should the nurse take?
A. Administer the first dose as ordered and reassess respirations
in 15 minutes.
B. Hold the codeine, institute supplemental oxygen, and notify
the prescriber about possible ultrarapid CYP2D6 metabolism
risk.
C. Give half the ordered dose of codeine and document the
reduced dose.
,D. Substitute oral acetaminophen without notifying the
prescriber because nonopioid analgesia is safer.
Correct answer: B
Rationale — Correct (B):
Codeine is a prodrug metabolized by CYP2D6 to morphine;
patients who are ultrarapid metabolizers can develop life-
threatening respiratory depression. Given shallow respirations
and low O₂ saturation, holding the opioid, supporting
oxygenation, and notifying the prescriber (and flagging
pharmacogenomic risk) is the safest action. Davis highlights
pharmacogenomic variability (CYP2D6) and the need to
avoid/suspend opioids when respiratory compromise is present.
Rationale — Incorrect:
A. Administering when the patient already shows
hypoventilation risks worsening respiratory depression;
reassessment after giving an opioid is unsafe.
C. Arbitrary dose reduction without prescriber/MD order and
without addressing oxygenation still risks harm and doesn’t
address metabolic variability.
D. Substituting without prescriber notification is a medication-
use delegation error and may not provide adequate pain control
immediately.
Teaching point: Hold opioids for respiratory compromise and
consider CYP2D6 phenotype.
Citation (APA): Vallerand, A. H., & Sanoski, C. A. (2025). Davis's
Drug Guide for Nurses (19th ed.). [Pharmacogenomics].
,2) Clopidogrel — Antiplatelet (P2Y12 inhibitor) — The
Cytochrome P450 System & Drug Interactions (Nursing
Implications)
Stem: A patient with a recent coronary stent is taking
clopidogrel. The provider prescribes omeprazole for reflux.
Which nursing action is most appropriate before administering
both medications?
A. Administer both agents as ordered; document both in the
MAR.
B. Hold clopidogrel and notify the prescriber immediately to
request discontinuation.
C. Recognize potential CYP2C19 inhibition by omeprazole,
withhold omeprazole if possible, and discuss alternative PPI (or
H2 blocker) with prescriber.
D. Give clopidogrel with a high-fat meal to increase absorption
and add omeprazole at bedtime.
Correct answer: C
Rationale — Correct (C):
Clopidogrel is a CYP2C19-activated prodrug; potent CYP2C19
inhibitors (omeprazole) can reduce activation and antiplatelet
effect, increasing thrombosis risk. The nurse should identify the
interaction, withhold/avoid starting omeprazole if feasible, and
consult the prescriber for an alternative — this matches safe
medication-use guidance on CYP interactions.
, Rationale — Incorrect:
A. Co-administration without review risks clinically significant
loss of clopidogrel efficacy.
B. Holding clopidogrel without prescriber input endangers the
patient with stent thrombosis.
D. Food manipulation won’t overcome the metabolic
interaction and is irrelevant to CYP2C19 inhibition.
Teaching point: Check CYP450 interactions before adding PPIs
with prodrugs like clopidogrel.
Citation (APA): Vallerand, A. H., & Sanoski, C. A. (2025). Davis's
Drug Guide for Nurses (19th ed.). [The Cytochrome P450
System; Drug Interactions].
3) Isotretinoin — Retinoid (teratogen) — Overview of REMS &
Females of Reproductive Potential (Patient/Family Teaching;
Nursing Implications)
Stem: A 22-year-old woman is admitted for isotretinoin therapy
and reports inconsistent contraception. A pregnancy test in
triage is positive. Which is the nurse’s best action?
A. Proceed with the first dose because isotretinoin is most
teratogenic only during the first trimester.
B. Hold the medication, notify the prescriber, and follow REMS
enrollment/pregnancy-prevention program requirements.
C. Administer as ordered and provide contraception counseling
at discharge.
