A nurse is providing teaching to a client who has stable angina and a new prescription for nitroglycerin oral, sustained-release capsules. Which of the following instructions should the nurse include?

Hypokalemia is a low serum potassium level, usually below 3.5 mEq/L. It can be caused by diuretics that increase potassium excretion, such as thiazides or loop diuretics. Potassium is essential for normal muscle and nerve function, and hypokalemia can impair cardiac, skeletal, and smooth muscle activity. Symptoms of hypokalemia include fatigue, weakness, muscle cramps, arrhythmias, constipation, and hyporeflexia.

1. Dyspnea is difficulty or labored breathing that can be caused by various respiratory or cardiac conditions, such as asthma, pneumonia, pulmonary edema, or heart failure. It is not a specific sign of hypokalemia, although severe hypokalemia can affect respiratory muscle function and cause respiratory failure.
2. Oliguria is a reduced urine output, usually less than 400 mL per day or 30 mL per hour. It can be caused by various renal or fluid balance disorders, such as acute kidney injury, dehydration, or shock. It is not a specific sign of hypokalemia, although severe hypokalemia can impair renal function and cause renal failure.
3. Pitting edema is a swelling of the tissues that leaves an indentation when pressed with a finger. It can be caused by various fluid retention disorders, such as heart failure, liver cirrhosis, or nephrotic syndrome. It is not a specific sign of hypokalemia, although severe hypokalemia can affect fluid and electrolyte balance and cause edema.

Nitroglycerin is a vasodilator that relaxes smooth muscle in blood vessels and reduces myocardial oxygen demand. It is used to treat and prevent angina atacks. A common side effect of nitroglycerin is headache, which is caused by cerebral vasodilation. The nurse should advise the client to take a mild analgesic, such as acetaminophen, to relieve the headache. The headache usually subsides with continued use of nitroglycerin.

The other options are not correct because:

"Take only one dose of nitroglycerin to reduce the risk of getting a headache." This statement is incorrect because it may compromise the effectiveness of nitroglycerin in relieving angina. The client should follow the prescribed dosage and frequency of nitroglycerin, which is usually one tablet every 5 minutes for up to three doses, as needed for chest pain.

"There's nothing that can be done to relieve the headaches that nitroglycerin causes." This statement is incorrect because it is discouraging and dismissive of the client's concern. The nurse should acknowledge the client's

discomfort and offer suggestions for managing the side effect, such as taking a mild analgesic or lying down in a dark room.

"We will ask the provider to prescribe a different medication for you." This statement is incorrect because it implies that nitroglycerin is not suitable for the client and may cause unnecessary anxiety or confusion. The nurse should explain that nitroglycerin is an effective and safe medication for angina and that the headache is a common and transient side effect that can be managed with simple measures. The nurse should also inform the client that there are other forms of nitroglycerin, such as patches or sprays, that may have less headache-inducing effects. However, changing the medication or the route of administration should be done only after consulting with the provider.