A nurse is teaching a client who has a new prescription for a nitroglycerin transdermal patch.
Which of the following instructions should the nurse include?

Taking a high-ceiling diuretic predisposes this client to developing digoxin toxicity because it can cause hypokalemia (low blood potassium level), which increases the sensitivity of the heart to digoxin. Digoxin is a medicine that is used to treat heart failure or arrhythmias (abnormal heart rhythms) by increasing cardiac contractility and controlling the heart rate. Digoxin toxicity happens when there is too much digoxin in the body and it becomes harmful, causing symptoms such as nausea, vomiting, headache, confusion, vision disturbance, and irregular heartbeat.

Choice A is wrong because taking an HMG CoA reductase inhibitor (also called a statin) does not increase the risk of digoxin toxicity.

Statins are lipid-lowering medications used to prevent coronary heart disease by blocking an enzyme involved in cholesterol synthesis.

Statins do not affect the blood potassium level or the sensitivity of the heart to digoxin.

Choice B is wrong because having a 10-year history of COPD (chronic obstructive pulmonary disease) does not increase the risk of digoxin toxicity. COPD is a lung condition that causes breathing difficulties and chronic inflammation.

COPD does not affect the blood potassium level or the sensitivity of the heart to digoxin.

Choice D is wrong because having a prolapsed mitral valve does not increase the risk of digoxin toxicity.

A prolapsed mitral valve is a condition where the valve between the left atrium and left ventricle of the heart does not close properly, allowing some blood to leak back into the atrium.

A prolapsed mitral valve does not affect the blood potassium level or the sensitivity of the heart to digoxin.

Hyponatremia is a condition where the sodium level in the blood is too low, which can cause confusion, lethargy, seizures, and coma. A hypertonic solution is a fluid that has a higher concentration of solutes than the blood, which can help raise the sodium level and reduce the brain swelling caused by hyponatremia. Therefore, improved cognition indicates that the treatment is effective.

Choice B. Cardiac arrhythmias absent.

Cardiac arrhythmias are not a common symptom of hyponatremia unless it is severe or rapid in onset.

Therefore, their absence does not necessarily indicate that the treatment is effective.

Choice C. Decreased vomiting.

Vomiting can be a cause or a consequence of hyponatremia, depending on the underlying condition.

Decreased vomiting may indicate that the patient is less nauseated, but it does not reflect the sodium level or the brain status.

Choice D. Absent Chvostek’s sign.

Chvostek’s sign is a facial twitching that occurs when tapping on the cheek, which indicates hypocalcemia (low calcium level).

It is not related to hyponatremia or hypertonic solution.

Normal ranges for sodium are 135 to 145 mEq/L and for calcium are 8.5 to 10.5 mg/dL.