Which of the following medications does the nurse identify as a calcium channel blocker used to treat tachycardia and manage heart rate?
Digoxin
Diltiazem (Cardizem)
Nitroglycerin
Nitroprusside (Nipride)
The Correct Answer is B
Choice A rationale:
Digoxin is a cardiac glycoside, not a calcium channel blocker. It works by increasing the force of contraction of the heart muscle and slowing the heart rate. However, it is not typically used as a first-line treatment for tachycardia. It's more commonly used to treat heart failure and atrial fibrillation.
Mechanism of action: Digoxin inhibits the sodium-potassium ATPase pump in cardiac cells, leading to an increase in intracellular calcium. This increased calcium availability enhances myocardial contractility. Digoxin also indirectly affects the autonomic nervous system, leading to a decrease in heart rate.
Key points:
Digoxin is not a calcium channel blocker.
It's used primarily for heart failure and atrial fibrillation.
Its mechanism of action involves increasing intracellular calcium and decreasing heart rate.
Choice B rationale:
Diltiazem (Cardizem) is a calcium channel blocker that is commonly used to treat tachycardia and manage heart rate. It works by blocking the movement of calcium into cardiac cells, which slows down the electrical conduction system of the heart and leads to a decrease in heart rate.
Mechanism of action: Diltiazem blocks L-type calcium channels in cardiac and vascular smooth muscle cells. This reduces calcium influx, leading to:
Decreased myocardial contractility Vasodilation (relaxation of blood vessels)
Negative chronotropic effect (decreased heart rate)
Negative dromotropic effect (slowed conduction through the AV node) Key points:
Diltiazem is a calcium channel blocker.
It's effective in treating tachycardia and managing heart rate.
Its mechanism of action involves blocking calcium channels, leading to various cardiovascular effects.
Choice C rationale:
Nitroglycerin is a vasodilator, not a calcium channel blocker. It works by relaxing the smooth muscle in blood vessels, which widens the vessels and allows more blood to flow through them. This can help to relieve chest pain (angina) and lower blood pressure, but it does not directly affect heart rate.
Mechanism of action: Nitroglycerin is metabolized to nitric oxide, which activates guanylate cyclase, leading to increased production of cyclic guanosine monophosphate (cGMP). cGMP causes smooth muscle relaxation, resulting in vasodilation.
Key points:
Nitroglycerin is a vasodilator, not a calcium channel blocker. It's primarily used for angina and hypertension.
Its mechanism of action involves nitric oxide-mediated vasodilation.
Choice D rationale:
Nitroprusside (Nipride) is a potent vasodilator, not a calcium channel blocker. It is typically used in critical care settings to manage severe hypertension or heart failure. It works by relaxing the smooth muscle in blood vessels, which widens the vessels and allows more blood to flow through them. This can help to lower blood pressure, but it does not directly affect heart rate.
Mechanism of action: Nitroprusside directly releases nitric oxide, leading to vasodilation. Key points:
Nitroprusside is a potent vasodilator, not a calcium channel blocker.
It's used in critical care settings for severe hypertension or heart failure.
Its mechanism of action involves direct nitric oxide release and vasodilation.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Choice A rationale:
Fava beans do not interact with antithyroid medications and do not need to be avoided specifically for this reason. However, it's important to note that fava beans can cause a condition called favism in individuals with a certain genetic predisposition. Favism is characterized by hemolytic anemia, which is the breakdown of red blood cells. If a patient has a history of favism or is unsure of their risk, it's best to avoid fava beans while on antithyroid medication and consult with their healthcare provider.
Choice B rationale:
Shellfish does not typically interact with antithyroid medications. However, some individuals with hyperthyroidism may have co-existing allergies to shellfish. In those cases, it's important to avoid shellfish to prevent allergic reactions, but this is not due to a direct interaction with antithyroid medications.
Choice C rationale:
Foods high in purine, such as organ meats, red meat, and certain seafood, are often restricted in individuals with gout. Gout is a form of arthritis caused by the buildup of uric acid crystals in the joints. While hyperthyroidism can sometimes increase uric acid levels, there's no specific interaction between antithyroid medications and purine-rich foods. Therefore, avoiding purine- rich foods is not necessary for those on antithyroid therapy unless they have gout or a predisposition to it.
Choice D rationale:
Grapefruit and grapefruit juice can significantly interact with antithyroid medications, particularly methimazole and propylthiouracil. These medications are broken down by an enzyme called CYP3A4 in the liver. Grapefruit juice inhibits the activity of CYP3A4, which can lead to increased levels of antithyroid medications in the bloodstream. This can increase the risk of side effects from the medication, such as liver damage, bone marrow suppression, and skin reactions. Therefore, it's crucial for patients on antithyroid therapy to avoid grapefruit and grapefruit juice.
Correct Answer is A
Explanation
Choice A rationale:
Hypoglycemia is the most frequent side effect of insulin administration. It occurs when blood glucose levels drop too low, typically below 70 mg/dL.
Insulin is a hormone that plays a key role in regulating blood glucose levels. It works by promoting the uptake of glucose from the bloodstream into cells, where it can be used for energy.
When too much insulin is administered, or when blood glucose levels are already low, it can lead to hypoglycemia. Symptoms of hypoglycemia can vary, but they often include:
Shakiness Sweating Anxiety Hunger Palpitations Confusion Dizziness Blurred vision Seizures
Loss of consciousness
If hypoglycemia is not treated promptly, it can lead to serious complications, such as coma or death.
Therefore, it is important to be aware of the signs and symptoms of hypoglycemia and to take steps to prevent it. This may involve monitoring blood glucose levels regularly, adjusting insulin doses as needed, and carrying a source of fast-acting glucose, such as glucose tablets or juice, to treat hypoglycemia if it occurs.
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