Digoxin.
Know the drug.
Connect the cues.

Digoxin is a cardiac glycoside with a narrow therapeutic index: the margin between an effective dose and a harmful dose is small.

It inhibits the sodium–potassium ATPase pump. This increases intracellular sodium, reduces calcium extrusion through the sodium–calcium exchanger, and increases calcium available for cardiac contraction. The result is positive inotropy—a stronger myocardial contraction.

Its vagal effects slow conduction through the atrioventricular (AV) node and can reduce heart rate. Remember: increasing the force of contraction does not mean increasing the rate.

1. Assess the apical pulse for one full minute. Note rate and rhythm; do not rely on a brief radial-pulse count.
2. Check the prescription's hold parameters. In adults, a pulse below 60 beats/min is a commonly taught reason to withhold and notify the provider. Individual orders and facility policy guide the decision.
3. Review recent electrolytes and trends. Pay particular attention to potassium and magnesium; calcium abnormalities also matter.
4. Review renal function. Rising creatinine, declining estimated GFR, or reduced urine output may suggest impaired clearance or acute kidney injury.
5. Ask about new symptoms. Appetite loss, nausea, vomiting, visual changes, dizziness, and a new irregular heartbeat deserve assessment.
6. Review the dose, last administration, and interacting medicines. Verify any loading-dose schedule and avoid accidental duplicate doses.

Administration essentials: verify the formulation and units. 0.125 mg = 125 micrograms. Use a calibrated oral syringe for liquid medication. Give IV digoxin slowly according to the product instructions and institutional policy, typically over at least 5 minutes; avoid rapid bolus administration.

Understand the range without falling into a trap.

For heart failure, a commonly recommended target is 0.5 to less than 0.9 ng/mL. Some laboratory reports and teaching resources list broader ranges around 0.5–2.0 ng/mL. The target depends on the clinical indication and patient.

Concentrations above 2 ng/mL are associated with increased toxicity risk, but toxicity can occur at lower levels. A “normal” concentration does not make a symptomatic patient safe.

Timing changes the meaning.

Collect a serum sample just before the next scheduled dose or at least 6 hours after the last dose. A sample drawn too soon can be misleading because distribution into tissues is incomplete.

Digoxin toxicity can affect several systems at once. Look for a cluster of cues, rather than waiting for one classic symptom.

Who is at greater risk?

Older adults, patients with low body weight, impaired renal function, hypokalemia, hypomagnesemia, hypercalcemia, or medicines that increase digoxin exposure. Dehydration or an acute illness can change previously stable renal function and electrolytes.

When toxicity is suspected, withhold the next digoxin dose, assess the patient, and notify the healthcare provider promptly. Obtain cardiac monitoring and ordered investigations, including electrolytes, renal function, and an appropriately timed digoxin level.

If the patient is unstable, prioritize emergency assessment and resuscitation according to protocol. A routine provider message or laboratory draw must not delay the response to a life-threatening rhythm or hemodynamic collapse.

Know the antidote: digoxin immune Fab.

Digoxin immune Fab binds digoxin and may be prescribed for life-threatening or severe toxicity. Monitor ECG, blood pressure, clinical response, potassium, and renal function.

• Potassium may fall rapidly after Fab treatment; monitor for hypokalemia.
• Routine total serum digoxin results can become misleading after Fab because the assay may measure bound as well as free digoxin. Follow clinical response and specialist guidance.
• Heart-failure symptoms or a rapid ventricular response in atrial fibrillation can recur as digoxin's therapeutic effect is reversed.

Know the important safety cautions.

Digoxin is contraindicated in ventricular fibrillation. In atrial fibrillation with an accessory pathway such as Wolff–Parkinson–White syndrome, AV-node slowing can promote a dangerously rapid ventricular response. Significant sinus-node disease or AV block also requires careful review.

Digoxin is not recommended in acute myocardial infarction and should be avoided in myocarditis. Question a concerning order and clarify it before administration.

• Take the exact prescribed dose at a consistent time. Do not stop or change it independently.
• Never double a missed dose. Follow the provided missed-dose instructions; ask the pharmacist if uncertain.
• Keep blood-test and follow-up appointments. Kidney function and electrolytes can change even when the dose stays the same.
• Report persistent nausea, vomiting, appetite loss, visual changes, or a new irregular heartbeat. Seek urgent help for fainting, severe weakness with a very slow pulse, or other signs of instability.
• If prescribed home pulse monitoring, demonstrate the technique and confirm the individual hold/report parameters.
• Review new medicines and supplements first. Do not independently start potassium supplements, potassium-containing salt substitutes, or herbal products.
• Follow the individualized diet plan. A patient with renal impairment may have different potassium instructions from a patient losing potassium through a diuretic.

Select one answer. The correct choice and the rationale for every option appear immediately. These are original educational practice questions.

For NCLEX study. Clinical administration follows the patient-specific prescription, current protocols, and professional assessment.