A patient with chronic stable angina is being treated with metoprolol (Lopressor). The nurse will suspect that the patient is experiencing a side effect of the metoprolol if:
The patient complains about feeling anxious.
The patient is restless and agitated.
The cardiac monitor shows a heart rate of 45.
The BP is 190/110 mm Hg.
The Correct Answer is C
Choice A rationale
Anxiety is generally not a common physiological side effect of beta-adrenergic antagonists like metoprolol. Instead, these medications often cross the blood-brain barrier and cause central nervous system depression, leading to symptoms such as fatigue, lethargy, or even depression. Anxiety is more commonly associated with the stimulation of the sympathetic nervous system or the use of beta-agonists, which would be the opposite pharmacological effect of this specific medication class.
Choice B rationale
Restlessness and agitation are typically signs of neurological irritability or hypoxia rather than direct side effects of beta-blocker therapy. Metoprolol works by blocking beta-1 receptors in the heart, which reduces the heart rate and myocardial contractility. Because it dampens the "fight or flight" response, patients are much more likely to experience a calming effect or sedation. Agitation would be an atypical response and might indicate a different underlying clinical complication.
Choice C rationale
Metoprolol is a cardioselective beta-1 adrenergic antagonist that decreases the heart rate by slowing the conduction through the atrioventricular node and reducing sinus node automaticity. A heart rate of 45 beats per minute represents significant bradycardia, as the normal adult resting range is 60 to 100 beats per minute. This profound slowing of the heart rate is a classic, expected, and potentially dangerous side effect of excessive beta-blockade requiring nursing intervention.
Choice D rationale
A blood pressure of 190/110 mm Hg indicates severe hypertension, whereas metoprolol is specifically used to lower blood pressure. Beta-blockers reduce cardiac output and inhibit the release of renin from the kidneys, which normally leads to a decrease in systemic vascular resistance and lower blood pressure readings. A hypertensive crisis of this magnitude would suggest that the medication is either ineffective or that the patient is experiencing a paradoxical reaction or withdrawal.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
Choice A rationale
Supraventricular tachycardia (SVT) is characterized by a regular, very rapid heart rate that typically exceeds 150 beats per minute. In SVT, the P waves are often buried in the preceding T waves because the rate is so fast that the electrical activity overlaps. While this rhythm involves a rapid rate, it does not match the specific criteria for SVT if the rate is lower or if distinct P waves are clearly visible before every QRS complex.
Choice B rationale
Normal sinus rhythm (NSR) is the standard electrical activity of the heart, originating from the sinoatrial node. It must have a regular rate between 60 and 100 beats per minute in an adult. Each QRS complex must be preceded by a normal P wave with a consistent PR interval. If the rate exceeds 100 beats per minute, it no longer meets the definition of NSR and must be classified as a tachycardia, even if all other waves look normal.
Choice C rationale
Sinus tachycardia is defined as a sinus rhythm with a heart rate greater than 100 beats per minute in an adult, typically ranging from 101 to 180 beats per minute. It maintains a regular rhythm where each QRS complex is preceded by a visible P wave, indicating the sinoatrial node is still the primary pacemaker. This occurs due to increased sympathetic stimulation, exercise, fever, or pain, reflecting a normal physiological response to various stressors on the body.
Choice D rationale
Bigeminy is a specific type of arrhythmia characterized by a repeating pattern where every second beat is a premature contraction, most commonly a premature ventricular contraction (PVC). This results in a "grouped beating" appearance on the EKG strip rather than a continuous, fast, regular rate. Because bigeminy involves an irregular rhythm with alternating beat morphologies, it is distinctly different from a sinus-driven tachycardia where all the QRS complexes appear uniform and regular.
Correct Answer is A
Explanation
Choice A rationale
Atropine is an anticholinergic medication that blocks the effects of the vagus nerve on the sinoatrial node. This action increases the heart rate, which is the primary goal when treating symptomatic sinus bradycardia. By increasing the heart rate, cardiac output is improved, helping to resolve hypotension and dizziness. A normal heart rate is 60 to 100 beats/min; therefore, a rate below 60 accompanied by clinical symptoms requires this rapid pharmacological intervention.
Choice B rationale
Digoxin is a cardiac glycoside used to treat heart failure and certain atrial arrhythmias like atrial fibrillation. It has positive inotropic effects but also possesses negative chronotropic properties, meaning it slows the heart rate by increasing vagal tone and slowing conduction through the atrioventricular node. Administering digoxin to a patient who is already bradycardic and symptomatic would be contraindicated, as it would likely worsen the low heart rate and associated dizziness.
Choice C rationale
Lidocaine is a Class 1b antiarrhythmic primarily used to treat ventricular arrhythmias, such as premature ventricular contractions or ventricular tachycardia. It works by blocking sodium channels in the myocardial cell membranes. It does not have a role in increasing the heart rate for sinus bradycardia. Using it in this context provides no benefit for the bradycardia and could potentially introduce unwanted side effects without addressing the underlying cause of the hypotension.
Choice D rationale
Metoprolol is a beta-adrenergic blocker that decreases the heart rate, blood pressure, and myocardial oxygen demand by blocking beta-1 receptors. Like digoxin, it is a negative chronotrope and is specifically contraindicated in patients with sinus bradycardia or high-degree heart blocks. Giving metoprolol to a patient with a slow heart rate and hypotension would dangerously exacerbate the condition, potentially leading to a complete circulatory collapse or cardiogenic shock.
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