DAVIS'S DRUG GUIDE FOR NURSES
19TH EDITION
• AUTHOR(S)APRIL HAZARD
VALLERAND; CYNTHIA SANOSKI
TEST BANK
1
Drug Reference
Pharmacotherapeutics & Evidence-Based Practice — Evidence-
Based Practice and Pharmacotherapeutics (Nursing Implications
& Monitoring)
Stem
A 58-year male with newly diagnosed atrial fibrillation is
admitted; the provider orders warfarin for stroke prophylaxis.
Baseline INR is 1.0, and the patient reports starting a new
herbal supplement of St. John’s wort 2 weeks ago. Which action
should the nurse take before administering the first dose of
warfarin?
,A. Administer warfarin as ordered and schedule INR checks in 5
days.
B. Hold warfarin and notify the prescriber about potential herb–
drug interactions.
C. Administer half the ordered dose and recheck INR in 24
hours.
D. Ask the patient to stop St. John’s wort and give warfarin now.
Correct Answer: B
Rationales
B (Correct) — St. John’s wort can induce hepatic enzymes
and decrease warfarin effect, increasing thromboembolic risk.
Holding the first dose and notifying the prescriber supports
evidence-based, safe initiation while the team assesses
interaction risk and determines monitoring or dose
adjustments. This aligns with pharmacotherapeutic nursing
implications for interactions and monitoring.
A — Administering without addressing the herb risks
subtherapeutic anticoagulation; waiting 5 days to check INR
may be too late.
C — Arbitrary dose reduction is not an evidence-based
substitute for provider assessment and may provide inadequate
anticoagulation.
D — Telling the patient to stop the herb without prescriber
notification and still giving warfarin ignores the need for clinical
decision and could be unsafe.
,Teaching point: Always notify prescriber of herbal supplements
before starting interacting medications.
Citation: Vallerand, A. H., & Sanoski, C. (2025). Davis's Drug
Guide for Nurses (19th ed.). [Evidence-Based Practice and
Pharmacotherapeutics].
2
Drug Reference
Pharmacogenomics — Pharmacogenomics (Nursing
Implications & Patient Teaching)
Stem
A 32-year female of Ashkenazi Jewish descent is prescribed
mercaptopurine for inflammatory bowel disease. The prescriber
orders TPMT (thiopurine methyltransferase) genotype testing.
Which nursing action most appropriately uses
pharmacogenomics to prevent harm?
A. Administer the usual starting dose; monitor CBC weekly.
B. Hold medication until TPMT results return and notify
prescriber of family history.
C. Start at half the usual dose and obtain TPMT results later.
D. Give the full dose but obtain baseline liver enzymes only.
Correct Answer: B
Rationales
B (Correct) — TPMT deficiency increases risk of life-
, threatening myelosuppression with mercaptopurine. Holding
until genotype results and notifying the prescriber uses
pharmacogenomic data to avoid severe toxicity and tailor
dosing. This reflects high-priority, preventive medication safety.
A — Administering a standard dose before TPMT status
risks profound neutropenia if deficient.
C — Empiric dose reduction may still be unsafe and is not a
substitute for definitive genotype-guided dosing.
D — Liver enzymes alone do not identify TPMT deficiency;
CBC monitoring without genotype knowledge may be reactive
rather than preventive.
Teaching point: Pharmacogenomic testing (e.g., TPMT) prevents
severe drug-related myelosuppression.
Citation: Vallerand, A. H., & Sanoski, C. (2025). Davis's Drug
Guide for Nurses (19th ed.). [Pharmacogenomics].
3
Drug Reference
Medication Errors & Improving Practices — Medication Errors:
Improving Practices and Patient Safety (Nursing Implications)
Stem
During a busy med-pass, a nurse is interrupted and prepares
insulin glargine (long-acting) twice—once for Patient A (0700)
and once intended for Patient B (0830). The nurse is uncertain
19TH EDITION
• AUTHOR(S)APRIL HAZARD
VALLERAND; CYNTHIA SANOSKI
TEST BANK
1
Drug Reference
Pharmacotherapeutics & Evidence-Based Practice — Evidence-
Based Practice and Pharmacotherapeutics (Nursing Implications
& Monitoring)
Stem
A 58-year male with newly diagnosed atrial fibrillation is
admitted; the provider orders warfarin for stroke prophylaxis.
Baseline INR is 1.0, and the patient reports starting a new
herbal supplement of St. John’s wort 2 weeks ago. Which action
should the nurse take before administering the first dose of
warfarin?
,A. Administer warfarin as ordered and schedule INR checks in 5
days.
B. Hold warfarin and notify the prescriber about potential herb–
drug interactions.
C. Administer half the ordered dose and recheck INR in 24
hours.
D. Ask the patient to stop St. John’s wort and give warfarin now.
Correct Answer: B
Rationales
B (Correct) — St. John’s wort can induce hepatic enzymes
and decrease warfarin effect, increasing thromboembolic risk.
Holding the first dose and notifying the prescriber supports
evidence-based, safe initiation while the team assesses
interaction risk and determines monitoring or dose
adjustments. This aligns with pharmacotherapeutic nursing
implications for interactions and monitoring.
A — Administering without addressing the herb risks
subtherapeutic anticoagulation; waiting 5 days to check INR
may be too late.
C — Arbitrary dose reduction is not an evidence-based
substitute for provider assessment and may provide inadequate
anticoagulation.
D — Telling the patient to stop the herb without prescriber
notification and still giving warfarin ignores the need for clinical
decision and could be unsafe.
,Teaching point: Always notify prescriber of herbal supplements
before starting interacting medications.
Citation: Vallerand, A. H., & Sanoski, C. (2025). Davis's Drug
Guide for Nurses (19th ed.). [Evidence-Based Practice and
Pharmacotherapeutics].
2
Drug Reference
Pharmacogenomics — Pharmacogenomics (Nursing
Implications & Patient Teaching)
Stem
A 32-year female of Ashkenazi Jewish descent is prescribed
mercaptopurine for inflammatory bowel disease. The prescriber
orders TPMT (thiopurine methyltransferase) genotype testing.
Which nursing action most appropriately uses
pharmacogenomics to prevent harm?
A. Administer the usual starting dose; monitor CBC weekly.
B. Hold medication until TPMT results return and notify
prescriber of family history.
C. Start at half the usual dose and obtain TPMT results later.
D. Give the full dose but obtain baseline liver enzymes only.
Correct Answer: B
Rationales
B (Correct) — TPMT deficiency increases risk of life-
, threatening myelosuppression with mercaptopurine. Holding
until genotype results and notifying the prescriber uses
pharmacogenomic data to avoid severe toxicity and tailor
dosing. This reflects high-priority, preventive medication safety.
A — Administering a standard dose before TPMT status
risks profound neutropenia if deficient.
C — Empiric dose reduction may still be unsafe and is not a
substitute for definitive genotype-guided dosing.
D — Liver enzymes alone do not identify TPMT deficiency;
CBC monitoring without genotype knowledge may be reactive
rather than preventive.
Teaching point: Pharmacogenomic testing (e.g., TPMT) prevents
severe drug-related myelosuppression.
Citation: Vallerand, A. H., & Sanoski, C. (2025). Davis's Drug
Guide for Nurses (19th ed.). [Pharmacogenomics].
3
Drug Reference
Medication Errors & Improving Practices — Medication Errors:
Improving Practices and Patient Safety (Nursing Implications)
Stem
During a busy med-pass, a nurse is interrupted and prepares
insulin glargine (long-acting) twice—once for Patient A (0700)
and once intended for Patient B (0830). The nurse is uncertain
