A patient who has had an MI is taking a beta blocker.
What is the main benefit of beta blocker therapy for this patient?
Vasodilation of the coronary arteries.
Increased force of cardiac contraction.
Slowing of the heart rate.
Decreased oxygen demand.
Correct Answer : C,D
Choice A rationale
Beta-blockers, such as propranolol, are not known to cause vasodilation of the coronary arteries. These medications block the effects of epinephrine, which results in a reduction in heart rate and blood pressure, but they do not directly dilate the coronary arteries. The main effect is on cardiac workload and oxygen demand.
Choice B rationale
Beta-blockers primarily function by antagonizing the effects of catecholamines on beta-adrenergic receptors, leading to a decrease in the force of cardiac contraction (negative inotropic effect). This reduction in contractility lowers the heart's workload and oxygen demand, which is beneficial in post-MI patients, not by increasing it.
Choice C rationale
Beta-blockers produce a negative chronotropic effect by blocking beta-1 receptors in the sinoatrial (SA) node. This action slows the heart rate, allowing for increased diastolic filling time and improved coronary artery perfusion. This decreased heart rate also reduces myocardial oxygen consumption, which is crucial after a myocardial infarction.
Choice D rationale
By reducing heart rate, contractility, and blood pressure, beta-blockers significantly decrease the oxygen demand of the heart muscle. This is their primary therapeutic benefit following an MI. A lower myocardial oxygen demand helps to prevent further ischemia and limits the extent of myocardial damage.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Choice A rationale
Taking the medication before bed is incorrect. Thyroid replacement hormones, such as levothyroxine, can increase metabolism and may cause symptoms of insomnia or restlessness if taken too close to bedtime. Therefore, patients are advised to take the medication in the morning to align with the body's natural circadian rhythm and to minimize sleep disturbances.
Choice B rationale
The full therapeutic effects of thyroid replacement medication are not seen after one week. It typically takes several weeks, often four to six, for the medication to reach a steady-state level in the blood and for the patient to experience the full benefits. The dosage may also be adjusted based on subsequent blood tests and symptom assessment.
Choice C rationale
Stopping the drug because of insomnia is incorrect. Insomnia can be a symptom of hyperthyroidism (too much medication) or other factors. The patient should not abruptly stop the medication but should consult their healthcare provider. The provider can then assess the patient's symptoms, check thyroid hormone levels, and adjust the dosage if necessary, rather than ceasing treatment entirely.
Choice D rationale
Taking the medication in the morning on an empty stomach is correct. Levothyroxine absorption is significantly reduced when taken with food, especially those containing calcium, iron, or dietary fiber. Taking it in the morning, at least 30-60 minutes before breakfast, ensures consistent and optimal absorption, which is critical for maintaining stable thyroid hormone levels.
Correct Answer is A
Explanation
Choice A rationale
Levothyroxine is a synthetic form of the thyroid hormone thyroxine ($T_4$). It is the standard treatment for hypothyroidism, a condition characterized by an underactive thyroid gland that does not produce enough thyroid hormone to meet the body's metabolic needs.
Choice B rationale
Hyperthyroidism is a condition of excessive thyroid hormone production. Administering levothyroxine, which is a thyroid hormone supplement, would worsen the symptoms and metabolic state of a patient with hyperthyroidism, potentially leading to a thyroid storm.
Choice C rationale
While levothyroxine may be used as a suppressive therapy in certain types of thyroid cancer, it is not the primary treatment for the cancer itself. The main treatment for thyroid cancer is surgical removal of the thyroid gland, often followed by radioactive iodine therapy.
Choice D rationale
Thyroid storm is a life-threatening complication of hyperthyroidism. The condition is characterized by a massive surge of thyroid hormones. Levothyroxine would exacerbate this condition and is therefore contraindicated for patients in thyroid storm.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.