A nurse is caring for a client who has heart failure and a prescription for digoxin. Which of the following statements by the client indicates an adverse effect of the medication?

A. "I am urinating more frequently.": Increased urination is not a typical adverse effect of digoxin. However, it could be related to the diuretics often used alongside digoxin in heart failure management. B. "I've had a backache for several days.": Back pain is not a common adverse effect of digoxin. This could be related to other issues, but it is not typically associated with the medication. C. "I feel nauseated and have no appetite.": Nausea and loss of appetite are common signs of digoxin toxicity. If these symptoms occur, the nurse should assess the client for other signs of toxicity, such as confusion, vision changes, or irregular heart rhythms. D. "I can walk a mile a day.": This statement indicates that the client may be experiencing an improvement in their symptoms due to digoxin, not an adverse effect. Walking a mile a day suggests improved physical stamina, which is often the goal in heart failure treatment.