What should the nurse monitor before administering digoxin to a client?

Monitoring digoxin levels and potassium levels before administration is crucial because digoxin has a narrow therapeutic index, meaning the difference between a therapeutic dose and a toxic dose is small. Elevated digoxin levels can lead to toxicity, which may present with symptoms such as nausea, vomiting, visual disturbances, and arrhythmias. Checking the potassium level is also important, as hypokalemia (low potassium) can increase the risk of digoxin toxicity. Potassium competes with digoxin for binding at its site of action, so low potassium levels can enhance digoxin's effects and toxicity. Thus, ensuring both digoxin and potassium levels are in the correct range before administering the medication helps prevent adverse effects and ensures safe therapy.