NAPLEX Question of the Week: Oncology Supportive Care

Supportive Care is the subject of our question of the week!
NAPLEX Question of the Week: Oncology Supportive Care

BY, a 64-year-old female, presents to the oncology infusion center for her second cycle of chemotherapy. She was recently diagnosed with Stage II left breast cancer (ER-/PR+/HER2-) & her oncologist decided to treat her with the following regimen.

Doxorubicin 60 mg/m2 IV + Cyclophosphamide 600 mg/m2 IV Q2 weeks for 4 doses

Followed by:

Paclitaxel 80 mg/m2 IV weekly for 12 doses 

Due to the regimen’s high emetic risk, BY was also prescribed a 4-drug regimen, which includes ondansetron, Decadron, rolapitant, & Zyprexa, for chemotherapy-induced nausea & vomiting (CINV) prophylaxis. In addition, Transderm-Scop patch was added as treatment for breakthrough CINV. 

PMH: Hypertension, Diabetes, Stage II left breast cancer (ER-/PR+/HER2-)

Vitals: BP 123/76 mmHg, HR 81 bpm


A1c 6.1%

SCr 0.8 mg/dL

ALT 23 U/L, AST 19 U/L, Bilirubin 0.7 mg/dL

Current medications:

Lisinopril 40 mg QD

Glumetza 1000 mg QD

Ondansetron 24 mg on Day 1 of cycles

Decadron 20 mg on Day 1, 8 mg BID on Days 2-4 of cycles

Rolapitant 180 mg on Day 1 of cycles

Zyprexa 5 mg QD on Days 1-4 of cycles

Transderm-Scop 1.5 mg/3 days PRN 

At the clinic today, BY reports symptoms of dry mouth, blurred vision, & urinary retention that has started recently. She reports using all 5 medications.  Which of the following medications is most likely the culprit?

A. Decadron

B. Rolapitant

C. Zofran

D. Transderm-Scop

Answer with Rationale

Chemotherapy-induced nausea & vomiting (CINV), a debilitating side effect of cancer treatment, occurs as a result of neurotransmitter imbalances. It is both a physiological & psychological process that can lead to decreased quality of life & chemotherapy compliance. Antineoplastic therapy damages enterochromaffin cells lining the gastrointestinal tract which releases serotonin. Chemotherapy also alters modulation of dopamine & substance P in the CNS. Risk factors for CINV can be either patient-specific (female, age < 50 years, history of motion or morning sickness, etc.) or treatment-specific (emetogenicity of the agents in the regimen, dose/schedule/target area if radiation is used, etc). Studies have shown consistently that antiemetics, including 5-HT3 receptor antagonists, steroids, NK1 receptor antagonists, & atypical antipsychotics (e.g. olanzapine), are most effective as prophylaxis! 

Answer A is incorrect. Decadron suppresses normal immune response by decreasing inflammation through suppression of neutrophil migration, decreased production of inflammatory mediators, & reversal of increased capillary permeability. It also induces apoptosis in multiple myeloma cells. Its mechanism of antiemetic activity is unknown. Common side effects include adrenal suppression, euphoria/anxiety, insomnia, increase appetite, hyperglycemia, & osteoporosis. But the current side effects BY is experiencing are not associated primarily with corticosteroids. 

Answer B is incorrect. Rolapitant selectively & competitively inhibits substance P/neurokinin 1 (NK1) receptor to prevent delayed nausea & vomiting associated with emetogenic chemotherapy. Common side effects include hiccups, increased liver function tests, constipation, weakness, & fatigue.

Answer C is incorrect. Ondansetron, a selective 5-HT3 receptor antagonist, works by blocking serotonin both peripherally on vagal nerve terminals & centrally in the chemoreceptor trigger zone. Common side effects include QT prolongation, headache, somnolence, dizziness, constipation, & diarrhea.

Answer D is correct. Transderm-Scop blocks the action of acetylcholine at parasympathetic sites in smooth muscle, secretory glands, & the CNS. Common side effects include dry mouth, visual disturbances (blurred vision, mydriasis, etc.), urinary retention, & sedation. Onset of anticholinergic effects is very rapid with visual disturbances occurring within 1-2 days of patch application.

Generic/Brand: Doxorubicin (Adriamycin), Cyclophosphamide (Procytox), Paclitaxel (Taxol), Lisinopril (Zestril), Metformin (Glumetza or Glucophage), Ondansetron (Zofran), Dexamethasone (Decadron), Rolapitant (Varubi), Olanzapine (Zyprexa), Scopolamine (Transderm-Scop)

NAPLEX Core Competencies Covered:

  • 1.2 – From patients: treatment adherence, or medication-taking behavior; chief complaint, medication history, medical history, family history, social history, lifestyle habits, socioeconomic background
  • 1.5 – Signs or symptoms of medical conditions, healthy physiology, etiology of diseases, or pathophysiology
  • 2.1 – Pharmacology, mechanism of action, or therapeutic class
  • 2.2 – Commercial availability; prescription or non-prescription status; brand, generic, or biosimilar names; physical descriptions; or how supplied
  • 3.7 – Adverse drug effects, toxicology, or overdose

Create a Free MyAccess Profile

AccessMedicine Network is the place to keep up on new releases for the Access products, get short form didactic content, read up on practice impacting highlights, and watch video featuring authors of your favorite books in medicine. Create a MyAccess profile and follow our contributors to stay informed via email updates.