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 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.
Correct Answer is ["A","B","D","E","F","G","H","J"]
Explanation
● Weight 98 lbs: This information helps determine the patient's baseline weight and assess for potential weight loss associated with dehydration.
● Dehydrated: The diagnosis of dehydration indicates a critical condition that requires immediate attention and intervention.
● Lethargy: Lethargy suggests a decreased level of consciousness and could indicate a severe state of dehydration or other underlying issues that need to be addressed promptly.
● HR 122: A heart rate of 122 beats per minute is elevated and may indicate compensatory mechanisms in response to dehydration or other underlying conditions. It requires further evaluation and intervention.
● Shortness of Breath: This symptom suggests respiratory distress and may be related to the patient's dehydration or underlying conditions. It requires immediate assessment and intervention.
● Temperature 100: An elevated temperature may indicate an underlying infection or inflammatory response. It requires further evaluation to determine the cause and guide appropriate treatment.
● Thirsty: The patient's report of feeling thirsty is an important symptom indicating dehydration and the need for fluid replacement.
● BP 90/50: A blood pressure of 90/50 is low and may be indicative of hypotension, which can occur in dehydration. It requires close monitoring and intervention to stabilize the patient's blood pressure.
The following items are not immediate concerns based on the given information: ● Admitted to the ER: While it is important information, it is not a current concern as the patient is already in the ER.
● Female: The patient's gender is not an immediate concern for the assessment and management of dehydration.
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