A nurse is preparing to administer digoxin to a client who has heart failure. Which of the following actions is appropriate?

Choice A reason: Clients taking digoxin should maintain normal potassium levels. Hypokalemia increases the risk of digoxin toxicity because potassium competes with digoxin for binding sites on myocardial cells. Encouraging low potassium intake is inappropriate and potentially harmful. Choice B reason: Nausea, vomiting, and anorexia are early signs of digoxin toxicity. Monitoring for these symptoms is essential before administration. Toxicity can progress to visual disturbances and life-threatening arrhythmias, so early detection is critical. Choice C reason: Apical pulse should be measured for a full minute, not 30 seconds, to accurately assess for bradycardia or arrhythmias. Digoxin can cause heart rate changes, and a full-minute assessment ensures safe administration. Choice D reason: Digoxin is typically withheld if the heart rate is below 60/min, not above 100/min. A high heart rate may indicate worsening heart failure or another condition, but it is not a contraindication for digoxin administration.