A nursing instructor is teaching a group of nursing students about antihistamines. Which statement by a student indicates an understanding of the mechanism of action of the antihistamines?
"Antihistamines block release of histamine from mast cells and basophils."
"Antihistamines block H1 receptors to prevent actions of histamine at these sites."
"H1 antagonists can bind to H1 receptors, H2 receptors, and muscarinic receptors."
"First-generation antihistamines are more selective than second-generation antihistamines."
The Correct Answer is B
Antihistamines primarily work by blocking the H1 receptors, which are the receptors responsible for mediating the actions of histamine in the body. By blocking these receptors, antihistamines prevent or reduce the effects of histamine, such as itching, sneezing, runny nose, and watery eyes. This is the main mechanism by which antihistamines provide their therapeutic effects. "Antihistamines block release of histamine from mast cells and basophils." This statement is incorrect. Antihistamines do not block the release of histamine; instead, they block the histamine receptors to prevent the effects of histamine.
"H1 antagonists can bind to H1 receptors, H2 receptors, and muscarinic receptors." This statement is incorrect. H1 antagonists, or H1 receptor blockers, specifically bind to H1 receptors and do not have significant affinity for H2 receptors or muscarinic receptors. "First-generation antihistamines are more selective than second-generation antihistamines." This statement is incorrect. First-generation antihistamines are generally less selective and can have more sedating and anticholinergic effects compared to second-generation antihistamines, which are designed to be more selective for H1 receptors and have reduced sedative properties.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
The red tag is used to identify patients with critical injuries who require immediate medical attention. These individuals have life-threatening conditions that, with prompt medical intervention, have a higher chance of survival.
The triage color code system typically follows the following priority order:
1. Red tag: Immediate or emergent care needed for life-threatening injuries or conditions.
2. Yellow tag: Urgent care needed for significant injuries or conditions that are not immediately life-threatening.
3. Green tag: Non-urgent care needed for minor injuries or illnesses that can wait for medical treatment.
4. Black tag: Comfort care or deceased, as the injuries or conditions are incompatible with life or resources are not available for treatment.
Correct Answer is B
Explanation
Gentamicin is an antibiotic that is usually administered via IV infusion. The peak level is the highest concentration of the medication in the bloodstream, and it is important to monitor it to ensure therapeutic levels are achieved without reaching toxic levels.
Drawing the peak level 30 minutes after the infusion is complete allows enough time for the medication to distribute throughout the body and reach its peak concentration. This timing provides an accurate representation of the highest drug concentration in the bloodstream. 30 minutes before starting the infusion: Drawing the peak level before starting the infusion would not accurately reflect the peak concentration of the medication in the bloodstream. Immediately before the next dose of Gentamicin: Drawing the peak level immediately before the next dose would not provide an accurate assessment of the highest drug concentration, as the levels would have started to decrease due to elimination.
1 hour after infusion is complete: Waiting for 1 hour after the infusion is complete may result in missing the actual peak concentration of the medication in the bloodstream, as it may have already started to decline.
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