# A nurse cares for a 78-year-old client with chronic heart failure and atrial fibrillation taking digoxin 0.25 mg orally daily. The serum digoxin level returns at 2.4 ng/mL. Which findings should the nurse identify as consistent with digoxin toxicity? Select all that apply.

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> language: en  
> subject: Adverse Effects/Contraindications/Interactions  
> category: PPT

## Question

A nurse cares for a 78-year-old client with chronic heart failure and atrial fibrillation taking digoxin 0.25 mg orally daily. The serum digoxin level returns at 2.4 ng/mL. Which findings should the nurse identify as consistent with digoxin toxicity? Select all that apply.

1

New onset anorexia, nausea, and vomiting

2

Apical pulse 88 beats per minute and regular rhythm

3

Reports of yellow-green halos around lights and blurred vision

4

Serum potassium 3.0 mEq/L

5

Apical pulse 48 beats per minute with an irregular rhythm

## Explanation

A digoxin concentration of 2.4 ng/mL is above commonly used reference ranges and is especially concerning in an older client with compatible findings. Toxicity can cause new anorexia, nausea, or vomiting (option 1), yellow-green halos or blurred vision (option 3), and bradycardia or dysrhythmias (option 5). A potassium level of 3.0 mEq/L (option 4) increases myocardial sensitivity to digoxin and raises toxicity risk. A regular apical pulse of 88/min (option 2) is not a finding of digoxin toxicity.

## In-depth explanation

Clinical Judgment
Digoxin therapeutic 0.5-2.0 ng/mL. Toxicity signs: bradycardia <60, AV block, halos/blurred vision, GI upset, hypokalemia potentiation. Hold digoxin and notify provider if HR <60 or signs of toxicity. Antidote for severe toxicity: digoxin immune Fab (Digibind).

Memory Tip
Dig tox: Bradycardia + Halos + GI + Low K — HOLD + Digibind

KR vs U
AHA heart failure guidelines and Korean Society of Heart Failure align: digoxin level 0.5-0.9 ng/mL preferred for HF (lower than the older 0.5-2.0 historical range). Korean tertiary cardiology routinely measures levels and corrects K/Mg. Dig immune Fab available in both jurisdictions.

## Clinical scenario

Clinical Practice Guide
Interpret a digoxin concentration together with symptoms, renal function, electrolyte status, dose timing, and interacting medications. Draw a serum concentration at least 6 to 8 hours after the last dose so distribution is complete. Older age, renal impairment, hypokalemia, hypomagnesemia, and interacting drugs increase toxicity risk. Concerning findings include anorexia, nausea or vomiting, visual changes, bradycardia, and dysrhythmias. Hold the dose and notify the provider when toxicity is suspected; severe or life-threatening toxicity may require digoxin immune Fab under emergency or toxicology guidance.

## Key concepts

- **Digoxin** — Cardiac glycoside that increases contractility and slows AV conduction. Used for atrial fibrillation rate control and HFrEF symptoms. Narrow therapeutic index 0.5-2.0 ng/mL. Hypokalemia, hypomagnesemia, and hypercalcemia potentiate toxicity. Antidote: digoxin immune Fab.
- **Digoxin toxicity classic findings** — Bradycardia and AV block, GI (anorexia/nausea/vomiting), neurologic (confusion, weakness, fatigue), visual (yellow-green halos, blurred or yellow vision), arrhythmias including bigeminy and ventricular ectopy. Hypokalemia worsens toxicity.
- **Digoxin immune Fab (Digibind)** — Antidote for severe digoxin toxicity. Indications: life-threatening arrhythmia, hyperkalemia >5 with toxicity, level >10 ng/mL, large overdose. Each vial neutralizes 0.5 mg digoxin. Onset 30 minutes; full effect 4 hours. Recheck level 24 hours later.

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