MCQ Quiz- Cardioactive Steroids

MCQ Quiz: Cardioactive Steroids (Digoxin)

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Cardioactive steroids, with digoxin being the primary example, are a historic and complex class of medications used in the management of heart failure and atrial fibrillation. Their narrow therapeutic index and susceptibility to numerous interactions demand a profound understanding from any pharmacist. This quiz for PharmD students will test your knowledge of the intricate pharmacology, clinical application, pharmacokinetic principles, and toxicology of this important drug class.

1. What is the primary cellular mechanism of action for digoxin?

  • It blocks beta-1 adrenergic receptors in the heart.
  • It inhibits the sodium-potassium ATPase (Na+/K+-ATPase) pump in cardiac myocytes.
  • It blocks L-type calcium channels.
  • It inhibits angiotensin-converting enzyme.

Answer: It inhibits the sodium-potassium ATPase (Na+/K+-ATPase) pump in cardiac myocytes.

2. The inhibition of the Na+/K+-ATPase pump by digoxin leads to an increase in intracellular sodium, which then causes:

  • An increase in intracellular potassium.
  • A decrease in the activity of the Na+/Ca2+ exchanger, leading to increased intracellular calcium.
  • A decrease in intracellular calcium and a weaker contraction.
  • A direct stimulation of the sinoatrial (SA) node.

Answer: A decrease in the activity of the Na+/Ca2+ exchanger, leading to increased intracellular calcium.

3. The primary therapeutic effect resulting from digoxin’s mechanism of action is a:

  • Negative inotropic effect (decreased force of contraction).
  • Positive inotropic effect (increased force of contraction).
  • Positive chronotropic effect (increased heart rate).
  • Direct vasodilatory effect.

Answer: A positive inotropic effect (increased force of contraction).

4. In the management of atrial fibrillation, digoxin is used primarily to:

  • Convert the rhythm to normal sinus rhythm.
  • Prevent the formation of blood clots.
  • Control the ventricular rate by slowing AV nodal conduction.
  • Lower blood pressure.

Answer: Control the ventricular rate by slowing AV nodal conduction.

5. Which of the following is a key characteristic of digoxin’s pharmacokinetic profile?

  • It has a wide therapeutic index.
  • It is primarily metabolized by the liver.
  • It has a very short half-life.
  • It has a long half-life and is primarily eliminated by the kidneys.

Answer: It has a long half-life and is primarily eliminated by the kidneys.

6. The narrow therapeutic index of digoxin means that:

  • The drug is safe at any dose.
  • There is a small window between a therapeutic dose and a toxic dose.
  • It rarely causes side effects.
  • Therapeutic drug monitoring is not necessary.

Answer: There is a small window between a therapeutic dose and a toxic dose.

7. A patient with which of the following conditions is at the highest risk for digoxin toxicity?

  • Asthma
  • Gout
  • Renal impairment
  • Hypertension

Answer: Renal impairment

8. Which electrolyte imbalance significantly increases the risk of digoxin toxicity by increasing its binding to the Na+/K+-ATPase pump?

  • Hypokalemia (low potassium)
  • Hyperkalemia (high potassium)
  • Hyponatremia (low sodium)
  • Hypernatremia (high sodium)

Answer: Hypokalemia (low potassium)

9. A patient presents with nausea, vomiting, blurred yellow-green vision (xanthopsia), and cardiac arrhythmias. The pharmacist should suspect toxicity from which medication?

  • Metoprolol
  • Lisinopril
  • Amlodipine
  • Digoxin

Answer: Digoxin

10. What is the specific antidote for a life-threatening digoxin overdose?

  • Naloxone
  • Flumazenil
  • N-acetylcysteine
  • Digoxin immune Fab (DigiFab®)

Answer: Digoxin immune Fab (DigiFab®)

11. Which of the following medications can significantly increase digoxin levels by inhibiting the P-glycoprotein efflux pump?

  • Ranitidine
  • Metformin
  • Amiodarone and Verapamil
  • Hydrochlorothiazide

Answer: Amiodarone and Verapamil

12. When should a trough serum digoxin level be drawn to accurately assess a steady-state concentration?

  • Immediately after an oral dose.
  • 2 hours after an oral dose.
  • Just before the next scheduled dose, and at least 6-8 hours after the last dose.
  • At any random time during the day.

Answer: Just before the next scheduled dose, and at least 6-8 hours after the last dose.

13. In the management of heart failure with reduced ejection fraction (HFrEF), digoxin is typically used to:

  • Reduce mortality as a first-line agent.
  • Improve symptoms and reduce hospitalizations in patients who remain symptomatic despite guideline-directed medical therapy.
  • Replace the need for beta-blockers and ACE inhibitors.
  • Treat fluid overload.

Answer: Improve symptoms and reduce hospitalizations in patients who remain symptomatic despite guideline-directed medical therapy.

14. Which electrolyte abnormality can potentiate the effects of digoxin and increase the risk of toxicity?

  • Hypermagnesemia
  • Hypomagnesemia
  • Hyperphosphatemia
  • Hypophosphatemia

Answer: Hypomagnesemia

15. A patient taking digoxin and the loop diuretic furosemide requires careful monitoring because furosemide can cause:

  • Hyperkalemia.
  • Hypokalemia, increasing the risk of digoxin toxicity.
  • An increase in digoxin’s metabolism.
  • A decrease in digoxin’s absorption.

Answer: Hypokalemia, increasing the risk of digoxin toxicity.

16. The “digitalizing” or “loading dose” of digoxin is a strategy used to:

  • Slowly achieve a therapeutic level over several weeks.
  • Rapidly achieve a therapeutic concentration due to the drug’s long half-life.
  • Minimize the risk of side effects.
  • Fulfill an insurance requirement.

Answer: Rapidly achieve a therapeutic concentration due to the drug’s long half-life.

17. The cardioactive steroid structure of digoxin is derived from what natural source?

  • The willow bark tree.
  • The foxglove plant (Digitalis purpurea or Digitalis lanata).
  • A type of soil bacteria.
  • The venom of a snake.

Answer: The foxglove plant (Digitalis purpurea or Digitalis lanata).

18. Which of the following is a key counseling point for a patient starting digoxin?

  • To report any new symptoms like severe nausea, confusion, or changes in vision.
  • To double the dose if they miss a dose.
  • To take the medication with a high-fiber meal to increase absorption.
  • That the medication has no significant drug interactions.

Answer: To report any new symptoms like severe nausea, confusion, or changes in vision.

19. How does hyperkalemia affect the action of digoxin?

  • It increases digoxin’s binding to its receptor, potentiating its effect.
  • It has no effect on digoxin’s action.
  • It reduces digoxin’s binding to the Na+/K+-ATPase pump, potentially decreasing its effect.
  • It causes a rapid increase in the serum digoxin level.

Answer: It reduces digoxin’s binding to the Na+/K+-ATPase pump, potentially decreasing its effect.

20. In a geriatric patient, the starting dose of digoxin is generally lower due to:

  • The typical age-related decline in renal function.
  • The fact that older adults are less sensitive to the drug’s effects.
  • The lower prevalence of heart failure in this population.
  • The high cost of the medication.

Answer: The typical age-related decline in renal function.

21. The “negative chronotropic” effect of digoxin refers to its ability to:

  • Increase the force of contraction.
  • Decrease the heart rate.
  • Increase the speed of conduction.
  • Increase blood pressure.

Answer: Decrease the heart rate.

22. Which of the following is a contraindication for the use of digoxin?

  • Atrial fibrillation.
  • Heart failure.
  • Ventricular fibrillation.
  • Hypertension.

Answer: Ventricular fibrillation.

23. A pharmacist’s role in managing digoxin therapy includes:

  • Monitoring for drug interactions.
  • Educating the patient on the signs of toxicity.
  • Recommending dose adjustments based on renal function and serum levels.
  • All of the above.

Answer: All of the above.

24. The medicinal chemistry of cardioactive steroids reveals a core structure that includes a:

  • Steroid nucleus.
  • Lactone ring.
  • Sugar moiety (glycone).
  • All of the above.

Answer: All of the above.

25. The therapeutic range for digoxin when used for heart failure is typically:

  • 2.0 – 3.0 ng/mL
  • 1.5 – 2.5 ng/mL
  • 0.5 – 0.9 ng/mL
  • 2.0 ng/mL

Answer: 0.5 – 0.9 ng/mL

26. Which of the following is a direct effect of digoxin on the cardiac action potential?

  • It shortens the refractory period of the AV node.
  • It increases the automaticity of the SA node.
  • It increases the vagal tone to the heart, slowing conduction.
  • It blocks Phase 0 depolarization.

Answer: It increases the vagal tone to the heart, slowing conduction.

27. In a patient with atrial fibrillation and concurrent HFrEF, digoxin is a reasonable option for:

  • First-line rate control.
  • Anticoagulation.
  • Rate control, particularly if the patient is hypotensive and cannot tolerate a beta-blocker or non-DHP CCB.
  • Rhythm conversion.

Answer: Rate control, particularly if the patient is hypotensive and cannot tolerate a beta-blocker or non-DHP CCB.

28. A key part of the “Business Plan” for a pharmacist-led heart failure clinic would involve a protocol for:

  • The safe and appropriate initiation and monitoring of digoxin.
  • Marketing the clinic’s services.
  • The clinic’s financial projections.
  • The organizational structure of the clinic.

Answer: The safe and appropriate initiation and monitoring of digoxin.

29. A pharmacist’s “geriatric sensitivity” is crucial when managing digoxin because:

  • Older adults are more susceptible to its CNS side effects like confusion.
  • Polypharmacy increases the risk of drug interactions.
  • Renal function is more likely to be impaired.
  • All of the above.

Answer: All of the above.

30. The “Cardiovascular Principles” course provides the foundational knowledge that explains:

  • How digoxin’s effect on intracellular calcium leads to an increased force of contraction.
  • The legal requirements for dispensing digoxin.
  • The marketing strategies for brand-name digoxin.
  • The cost of digoxin therapy.

Answer: How digoxin’s effect on intracellular calcium leads to an increased force of contraction.

31. A pharmacist working in the “Virtual ICU” might be responsible for:

  • Remotely monitoring a patient’s heart rate and rhythm after digoxin initiation.
  • Recommending dose adjustments based on real-time lab data.
  • Screening for drug interactions in a complex ICU patient on digoxin.
  • All of the above.

Answer: All of the above.

32. The “leadership” skill of advocacy is demonstrated when a pharmacist:

  • Convinces an insurance company to cover the cost of Digoxin immune Fab for a patient with a life-threatening overdose.
  • Insists all heart failure patients receive digoxin.
  • Refuses to counsel any patient on digoxin.
  • Only dispenses brand-name Lanoxin®.

Answer: Convinces an insurance company to cover the cost of Digoxin immune Fab for a patient with a life-threatening overdose.

33. An “analytics and reporting system” in a hospital could be used to:

  • Identify all patients on digoxin who also have severe renal impairment to flag them for a pharmacist’s review.
  • Track the daily sales of digoxin.
  • Order digoxin from the wholesaler.
  • Generate a patient education leaflet.

Answer: Identify all patients on digoxin who also have severe renal impairment to flag them for a pharmacist’s review.

34. A “Clinical Decision Support” alert in the EHR should fire when a physician prescribes digoxin for a patient who is also on:

  • Metformin
  • Atorvastatin
  • Amiodarone.
  • Aspirin

Answer: Amiodarone.

35. From a “human factors” perspective, the fact that digoxin tablets are very small and come in multiple, similar strengths (e.g., 62.5 mcg, 125 mcg, 250 mcg) can increase the risk of:

  • Improved patient adherence.
  • A dispensing or administration error.
  • A lower cost for the medication.
  • A stock shortage.

Answer: A dispensing error.

36. A pharmacist’s ability to “negotiate” with a physician might be used to:

  • Discuss the risks versus benefits of continuing digoxin in a frail elderly patient with declining renal function.
  • Demand the physician change the dose.
  • Argue about the brand of digoxin to use.
  • Refuse to fill the prescription.

Answer: Discuss the risks versus benefits of continuing digoxin in a frail elderly patient with declining renal function.

37. The “financials” of using digoxin have changed over the years because:

  • It is a new, expensive brand-name drug.
  • Its use has declined in favor of newer HFrEF therapies, but it remains a low-cost option for specific indications.
  • The antidote is very inexpensive.
  • It is no longer covered by insurance.

Answer: Its use has declined in favor of newer HFrEF therapies, but it remains a low-cost option for specific indications.

38. The service of “deprescribing” is highly relevant to digoxin therapy because:

  • It is a medication that should be considered for discontinuation in elderly patients when the risks outweigh the benefits.
  • It should never be stopped once started.
  • It has no side effects.
  • It is a very safe medication.

Answer: It is a medication that should be considered for discontinuation in elderly patients when the risks outweigh the benefits.

39. Hypercalcemia can increase the risk of digoxin toxicity because calcium:

  • Competes with digoxin at the Na+/K+-ATPase pump.
  • Increases the renal clearance of digoxin.
  • Has a synergistic effect with digoxin on intracellular calcium levels, increasing the risk of arrhythmias.
  • Decreases the absorption of digoxin.

Answer: Has a synergistic effect with digoxin on intracellular calcium levels, increasing the risk of arrhythmias.

40. The reason digoxin is not a first-line therapy for HFrEF is that, unlike ACE inhibitors and beta-blockers, it has not been shown to:

  • Improve symptoms.
  • Reduce hospitalizations.
  • Reduce mortality.
  • Increase exercise tolerance.

Answer: Reduce mortality.

41. The large volume of distribution of digoxin means that:

  • Most of the drug is in the blood, and it can be easily removed by hemodialysis.
  • Most of the drug is in the peripheral tissues, and it cannot be effectively removed by hemodialysis.
  • The drug does not distribute outside the blood.
  • The drug is only distributed to the heart.

Answer: Most of the drug is in the peripheral tissues, and it cannot be effectively removed by hemodialysis.

42. Which of the following is NOT a classic sign of digoxin toxicity?

  • Nausea/vomiting
  • Bradycardia
  • Visual disturbances
  • Tachycardia

Answer: Tachycardia

43. A pharmacist’s knowledge of __________ is crucial for understanding why a patient with hypothyroidism may require a lower dose of digoxin.

  • Pharmacokinetics and altered metabolism/clearance
  • Medicinal chemistry
  • Health policy
  • Pharmacy marketing

Answer: Pharmacokinetics and altered metabolism/clearance

44. The use of a “Dashboard Presentation” in a hospital could be used to track:

  • The percentage of patients on digoxin who have had a serum level checked within the last year.
  • The pharmacy’s daily profits.
  • The number of technicians on the schedule.
  • The time it takes for a drug to be delivered from the wholesaler.

Answer: The percentage of patients on digoxin who have had a serum level checked within the last year.

45. Forging ahead in pharmacy practice means using clinical data to:

  • Justify the use of digoxin in all heart failure patients.
  • Ensure that high-risk drugs like digoxin are used safely and appropriately according to evidence-based guidelines.
  • Promote the use of more expensive alternatives.
  • Eliminate digoxin from all hospital formularies.

Answer: Ensure that high-risk drugs like digoxin are used safely and appropriately according to evidence-based guidelines.

46. The most important patient parameter to assess before every dose of digoxin in a hospital setting is:

  • Blood pressure.
  • Apical heart rate.
  • Respiratory rate.
  • Temperature.

Answer: Apical heart rate.

47. A key part of the “Business Plan” for a transitions of care service would be a protocol to manage:

  • High-risk medications like digoxin to prevent post-discharge adverse events.
  • The marketing of the service.
  • The financial projections for the service.
  • The organizational structure of the service.

Answer: High-risk medications like digoxin to prevent post-discharge adverse events.

48. In which “practice setting” is a pharmacist most likely to manage digoxin therapy based on serum levels and renal function?

  • A chain community pharmacy.
  • A hospital or an ambulatory care clinic.
  • A nuclear pharmacy.
  • A mail-order pharmacy.

Answer: A hospital or an ambulatory care clinic.

49. An effective “negotiation” with a patient who is fearful of digoxin’s side effects would involve:

  • Acknowledging their fears and providing clear, balanced information about the risks and benefits.
  • Dismissing their fears as irrational.
  • Refusing to dispense the medication.
  • Insisting they take the medication without further discussion.

Answer: Acknowledging their fears and providing clear, balanced information about the risks and benefits.

50. The ultimate reason a pharmacist must have a deep understanding of cardioactive steroids is to:

  • Pass the NAPLEX exam.
  • Ensure the safe and effective use of this narrow therapeutic index drug to improve patient outcomes.
  • Impress physicians with their knowledge.
  • Manage the pharmacy’s inventory of this drug.

Answer: Ensure the safe and effective use of this narrow therapeutic index drug to improve patient outcomes.

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