A client with Parkinson's disease is prescribed carbidopa-levadopa [Sinemet]. Which of the following side effects does the nurse recognize can occur with this medication?

A) Digoxin:
The client’s symptoms of confusion, vision disturbances (such as yellow halos around lights), and anorexia are all classic signs of digoxin toxicity. Digoxin, a cardiac glycoside, is commonly used in the treatment of heart failure and atrial fibrillation. However, it has a narrow therapeutic index, meaning that even slightly elevated blood levels can lead to toxicity. Other common symptoms of digoxin toxicity include bradycardia (which the client is also experiencing with a pulse of 53 bpm), nausea, and vomiting.

B) Diltiazem:
Diltiazem is a calcium channel blocker used to treat hypertension, angina, and atrial fibrillation. While it can cause bradycardia (as evidenced by the client’s pulse of 53 bpm), vision disturbances and anorexia are not typical side effects of this medication. More common side effects include hypotension, edema, and constipation.

C) Propranolol:
Propranolol is a beta-blocker used to treat hypertension, arrhythmias, and angina, as well as to prevent migraines. Bradycardia is a known side effect of beta-blockers, but vision disturbances and anorexia are not typical of propranolol. Moreover, propranolol can cause hypotension and fatigue but would not be as likely to cause the specific symptoms of confusion and vision changes seen in this client.

D) Captopril:
Captopril is an ACE inhibitor commonly used to treat hypertension and heart failure. Common side effects include hypotension, dizziness, and hyperkalemia, but vision disturbances and anorexia are not typical side effects of captopril. The symptoms the client is experiencing are more specific to digoxin toxicity than to captopril's side effects.

A) Peaked T waves:
Peaked T waves are a classic sign of hyperkalemia on an EKG. As potassium levels rise, the T waves become taller, more pointed, and narrow, indicating changes in the heart's electrical conduction. This is one of the earliest and most characteristic EKG changes seen with hyperkalemia. Hyperkalemia can result from conditions such as kidney dysfunction, use of potassium-sparing diuretics, or other electrolyte imbalances.

B) Inverted P waves:
Inverted P waves typically suggest issues such as atrial ischemia or ectopic atrial rhythms but are not a hallmark sign of hyperkalemia. They may also appear with other conditions, like atrial fibrillation or atrial flutter. However, inverted P waves are not typically linked to elevated potassium levels.

C) Widened QRS:
A widened QRS complex can occur in several conditions, including hyperkalemia, but it is generally seen in more severe cases. As potassium levels rise further, the QRS complex may widen due to delayed conduction through the ventricles. Although a widened QRS can indicate hyperkalemia, it is a later sign, and it typically occurs after more specific changes like peaked T waves.

D) Prominent U wave:
Prominent U waves are more often associated with hypokalemia (low potassium levels) rather than hyperkalemia. U waves are typically seen after the T wave on the EKG and can be more prominent in conditions of low potassium.