How does ephedrine act on the body?
Acts directly on alpha-Adrenergic receptor sites
Stimulates the release of norepinephrine
Acts directly on Beta-Adrenergic receptor sites
Stimulates the release of Dopamine
The Correct Answer is B
A) Acts directly on alpha-adrenergic receptor sites: Ephedrine does not act exclusively or directly on alpha-adrenergic receptors. While it can have some alpha-adrenergic effects, its primary mechanism is through the release of norepinephrine, which then activates both alpha and beta receptors. Therefore, this option is not entirely accurate for describing ephedrine's mode of action.
B) Stimulates the release of norepinephrine: Ephedrine primarily works by stimulating the release of norepinephrine from nerve terminals. The released norepinephrine then acts on both alpha and beta adrenergic receptors, leading to vasoconstriction (via alpha receptors) and increased heart rate and force of contraction (via beta receptors). This dual action helps raise blood pressure and improve cardiac output, making this the most accurate description of ephedrine's mechanism of action.
C) Acts directly on beta-adrenergic receptor sites: Although ephedrine does have beta-adrenergic effects (increasing heart rate and contractility), its primary mechanism is the indirect release of norepinephrine. It does not act directly on beta-receptors to the same extent as medications like isoproterenol. Therefore, while it does have beta-receptor activity, the main action is through norepinephrine release.
D) Stimulates the release of dopamine: Ephedrine does not primarily stimulate dopamine release. Dopamine release is more associated with drugs like levodopa or certain dopaminergic agents used in conditions like Parkinson’s disease. Ephedrine primarily affects norepinephrine and, to a lesser extent, acts on dopamine receptors, but it is not primarily a dopamine-releasing agent.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
A) Sweating: Sweating is a function of the sympathetic nervous system, not the parasympathetic nervous system. The sympathetic nervous system is responsible for the "fight or flight" response, which includes activating sweat glands. The parasympathetic system, in contrast, is more involved in "rest and digest" functions.
B) Pupil dilation: Pupil dilation (mydriasis) is mediated by the sympathetic nervous system through the activation of alpha-1 adrenergic receptors. The parasympathetic system causes pupil constriction (miosis) by stimulating muscarinic receptors in the eye, which is the opposite of pupil dilation.
C) Vasoconstriction: Vasoconstriction (narrowing of blood vessels) is generally a
function of the sympathetic nervous system, which releases norepinephrine to constrict blood vessels and increase blood pressure. The parasympathetic system typically causes vasodilation (widening of blood vessels) to promote relaxation and decreased blood pressure.
D) Anabolism: Anabolism refers to the metabolic processes that build up molecules and store energy, such as protein synthesis, cell growth, and energy storage. This is primarily mediated by the parasympathetic nervous system, which is involved in "rest and digest" functions. The parasympathetic system promotes activities that support energy conservation, digestion, and tissue repair, all of which support anabolic processes.
Correct Answer is C
Explanation
A) Suspect worsening of the anxiety disorder:
While it is possible that the patient's anxiety disorder is worsening, the more likely explanation for the reduced effectiveness of lorazepam is the development of drug tolerance. Over time, patients may require higher doses of a medication to achieve the same therapeutic effect, especially with medications like lorazepam that are used chronically.
B) Contact the provider to discuss changing to another benzodiazepine:
Changing to another benzodiazepine might be an option, but it is more likely that tolerance to lorazepam is the cause of the reduced effect, not an issue with the specific drug. Tolerance is common with long-term use of benzodiazepines, and switching drugs may not address the underlying issue. The first step would be to assess the current medication regimen and discuss possible adjustments with the provider.
C) Understand that the patient has developed tolerance to this drug:
Tolerance occurs when the body becomes accustomed to the effects of a medication over time, requiring higher doses to achieve the same therapeutic effect. This is a common phenomenon with benzodiazepines like lorazepam, which are often used for long periods to manage anxiety. As the patient has been taking lorazepam for six months, this reduced effectiveness is likely due to the development of tolerance, rather than a worsening of the anxiety disorder.
D) Notify the provider and discuss increasing the dose of lorazepam:
While increasing the dose of lorazepam could temporarily relieve symptoms, it is not the most appropriate first step. The nurse should first consider the possibility of tolerance and discuss this with the provider before increasing the dose. Long-term increases in benzodiazepine dosages can increase the risk of side effects, dependency, and withdrawal symptoms.
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