A nurse is caring for a client admitted to the intensive care unit for a cardiac dysrhythmia. The nurse understands the prescribed calcium channel blocker has which of the following mechanisms of action?
Acts on the beta cells within the heart and lungs to regulate cardiac rhythm
Increases heart rate and increases myocardial contractility
Reduces the contractility and conductivity of the heart
Increase oxygen to the systemic circulation
The Correct Answer is C
A) "Acts on the beta cells within the heart and lungs to regulate cardiac rhythm.": This statement is incorrect because calcium channel blockers do not primarily act on beta cells. Instead, they block calcium channels in cardiac and smooth muscle, which affects heart contractility and conductivity.
B) "Increases heart rate and increases myocardial contractility.": Calcium channel blockers typically do the opposite; they decrease heart rate and myocardial contractility by inhibiting calcium entry into the heart muscle cells. Therefore, this statement does not accurately describe their mechanism of action.
C) "Reduces the contractility and conductivity of the heart.": This statement accurately reflects the action of calcium channel blockers. By blocking calcium entry, these medications decrease myocardial contractility and slow down electrical conduction through the heart, which can help manage dysrhythmias.
D) "Increase oxygen to the systemic circulation.": While calcium channel blockers can improve blood flow and reduce myocardial oxygen demand by decreasing heart workload, their primary action does not directly focus on increasing oxygen delivery to systemic circulation. Their primary role is in managing heart contractility and rhythm.
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Correct Answer is A
Explanation
A) Heparin induced thrombocytopenia (HIT): Argatroban is an indirect thrombin inhibitor specifically used for anticoagulation in patients with HIT. This condition involves a significant drop in platelet counts due to heparin therapy, and argatroban is an appropriate alternative for preventing thrombosis in these patients.
B) Ventricular Dysfunction: While managing anticoagulation may be important in patients with ventricular dysfunction, this condition does not specifically necessitate the use of argatroban. Other anticoagulants may be used based on the clinical situation.
C) Myocardial infarction: Although anticoagulation may be warranted in the setting of a myocardial infarction, argatroban is not specifically indicated for this condition. Other antithrombotic therapies, such as aspirin or heparin, are more commonly used.
D) Hepatotoxicity: Argatroban is metabolized in the liver, so caution is warranted in patients with liver dysfunction. Hepatotoxicity itself would not be a reason to use argatroban; rather, it may require close monitoring or adjustment of dosage.
Correct Answer is D
Explanation
A) "Increase your potassium intake by eating more bananas and apricots.": Doxazosin is not a potassium-sparing medication, and there is no specific indication for increased potassium intake with this drug. This advice may be misleading, especially since excessive
potassium can pose risks, particularly in certain populations.
B) "Weigh yourself daily, and report any weight loss to your prescriber.": Daily weighing can be important for monitoring fluid retention in some conditions, but weight loss is not a common side effect of doxazosin. Instead, clients should be more concerned about weight gain due to fluid retention or potential side effects from the medication.
C) "The impaired taste associated with this medication usually goes away in 2 to 3 weeks.": Impaired taste is not a well-documented side effect of doxazosin. While some medications may cause changes in taste, this statement is not relevant for doxazosin and does not address the most critical aspects of its administration.
D) "Be sure to lie down after taking the first dose, because first-dose hypotension may make you dizzy.": This statement is accurate and important. Doxazosin can cause first-dose hypotension, leading to dizziness or fainting. Advising the client to lie down after the first dose helps mitigate the risk of hypotensive effects, making this the most appropriate emphasis for the nurse.