The nurse is administering atenolol (Tenormin) to a patient. Which concurrent drugs does the nurse expect to most likely cause an interaction? Select all that apply.
ginseng supplement
An NSAID, such as aspirin
atropine, an anticholinergic
haloperidol (Haldol)
methyldopa (Aldomet)
Correct Answer : B,C
Atenolol (Tenormin) is a cardioselective beta-1 blocker prescribed for hypertension, angina, and cardiac arrhythmias. Nurses must evaluate potential drug interactions that could reduce atenolol’s effectiveness or amplify its adverse effects, especially those that affect heart rate, blood pressure, or renal perfusion.
Rationale for correct answers:
2. An NSAID, such as aspirin – NSAIDs can reduce the antihypertensive effects of beta-blockers like atenolol by inhibiting renal prostaglandins, potentially increasing blood pressure.
3. Atropine, an anticholinergic – Atropine increases heart rate by blocking parasympathetic input, which may counteract atenolol’s beta-blocking effect, potentially complicating heart rate control.
Rationale for incorrect answers:
1. Ginseng supplement – While ginseng may have mild cardiovascular effects, it has not been shown to consistently interfere with atenolol. It is not a well-documented interaction.
4. Haloperidol (Haldol) – Although both drugs may prolong the QT interval, there is no direct, frequent interaction reported between haloperidol and atenolol affecting the drug's main mechanism.
5. Methyldopa (Aldomet) – Both methyldopa and atenolol lower blood pressure, but they are sometimes used together. Their additive effect is monitored, but this is not considered a strong or dangerous interaction.
Take-home points:
- NSAIDs can blunt the antihypertensive effect of beta-blockers like atenolol.
- Atropine may reduce atenolol's therapeutic effect by increasing heart rate.
- Always evaluate over-the-counter medications or supplements for potential cardiovascular interactions.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Propranolol (Inderal) is a non-selective beta-adrenergic blocker used to manage hypertension, arrhythmias, and angina. It works by blocking beta-1 and beta-2 receptors, leading to slowed heart rate and decreased cardiac output. Nurses must monitor cardiovascular and respiratory systems closely due to potential serious adverse effects.
Rationale for correct answer:
4. Bradycardia
Bradycardia is a major adverse effect due to beta-1 receptor blockade in the heart. Propranolol slows the SA node and AV node conduction, making it essential to monitor pulse and withhold the drug if the heart rate falls below safe limits (usually <60 bpm).
Rationale for incorrect answer:
1. Bronchodilation
Propranolol blocks beta-2 receptors in bronchial smooth muscle, which can cause bronchoconstriction, not bronchodilation. This effect is especially dangerous in clients with asthma or COPD.
2. Tachycardia
Propranolol decreases sympathetic stimulation of the heart, leading to slower heart rate, not tachycardia. It is often prescribed to prevent tachycardic conditions like atrial fibrillation or performance anxiety.
3. Edema
Edema is more commonly associated with calcium channel blockers or heart failure. Although beta blockers can worsen heart failure, peripheral edema is not a primary expected adverse effect of propranolol.
Take-home points:
- Propranolol causes bradycardia by blocking beta-1 receptors, reducing heart rate and cardiac output.
- It can also cause bronchoconstriction due to beta-2 blockade, so it must be used cautiously in patients with respiratory disease.
- Always assess pulse before administration and hold the medication if bradycardia is present.
Correct Answer is A
Explanation
Cholinergic overdose from medications like bethanechol results in excessive stimulation of the parasympathetic nervous system. Signs include bradycardia, hypotension, excessive salivation, and diarrhea. Atropine, a muscarinic antagonist, is the antidote used to reverse these effects.
Rationale for correct answer:
1. Atropine
Atropine is the first-line antidote for cholinergic toxicity. It competitively blocks muscarinic receptors, thereby reversing the muscarinic overstimulation seen in cholinergic overdose.
Rationale for incorrect answer:
2. Tolterodine
Although it is an anticholinergic used to treat overactive bladder, it is not typically used in emergencies or acute overdose situations.
3. Benztropine
Benztropine is an anticholinergic primarily used to treat extrapyramidal symptoms from antipsychotic drugs. It is not used as a cholinergic antidote.
4. Metoclopramide
This is a prokinetic and antiemetic drug with cholinergic activity, which could worsen symptoms of a cholinergic overdose.
Take-home points:
- Atropine is the antidote for cholinergic toxicity, such as from bethanechol overdose.
- Cholinergic overdose presents with symptoms like bradycardia, excessive salivation, and hypotension.
- Prompt recognition and reversal of parasympathetic overstimulation can prevent complications like respiratory distress or shock.
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