A client diagnosed with heart failure (HF) is prescribed fur…

A client diagnosed with heart failure (HF) is prescribed furosemide (Lasix), digoxin (Lanoxin), and potassium chloride. During the assessment the nurse finds that the client is nauseated, has a headache with blurred vision, reports feeling weak, and heart rate is 48 beats per minute (bpm).  Which complication is triggering these clinical manifestations?