NCLEX Answer: Digoxin and Potassium 3.1
The question: A client with heart failure takes digoxin 0.125 mg every morning. Today's lab results show a potassium level of 3.1 mEq/L. The client's apical pulse is 72. What should the nurse do?
A) Give the digoxin and recheck the potassium tomorrow
B) Hold the digoxin and notify the provider
C) Give the digoxin with a potassium-rich breakfast
D) Recheck the apical pulse for 30 seconds, then give the digoxin
✅ The answer is B) Hold the digoxin and notify the provider
Normal potassium is 3.5 to 5.0 mEq/L, so 3.1 is low. Low potassium makes the heart more sensitive to digoxin, which raises the risk of digoxin toxicity even when the dose hasn't changed. The safe move is to hold the dose and let the provider decide what's next.
How to decode it with my S.M.A.R.T. framework
- Scan for the clue: the question gives you two numbers, a pulse of 72 and a potassium of 3.1 mEq/L.
- Match it to context: the pulse is normal, but the potassium is low, and low potassium plus digoxin means a higher risk of toxicity.
- Analyze the opposites: a normal pulse pulls you toward “give it.” The potassium is the detail that says “don't.”
- Rule out distractors: A gives the dose today with a known low potassium. C relies on food, which won't raise potassium fast enough to make this morning's dose safe. D gives the dose, and an apical pulse before digoxin is counted for a full minute, not 30 seconds.
- Target the best answer: B) Hold the digoxin and notify the provider.
When a question hands you a med and a lab value, ask yourself: does this lab change whether this med is safe? You can know every fact about digoxin and still miss this question if you don't know how to read it. That's content plus strategy, and you need both to pass the NCLEX.
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