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."

Answer and Explanation

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.

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Correct Answer is D

Explanation

During triage in a disaster situation, a color tagging system is often used to prioritize and categorize the injured based on the severity of their injuries and the urgency of medical attention required. The colors commonly used in triage are:

● Green tag: Minor injuries that are non-urgent and can typically wait for medical treatment.

● Yellow tag: Injuries that are significant but not immediately life-threatening, requiring medical attention within a few hours.

● Red tag: Critical injuries that are life-threatening but still salvageable with prompt medical intervention.

● Black tag: Injuries that are severe and unsurvivable or incompatible with life. This tag is assigned to individuals who are deceased or have injuries that are beyond the resources available for treatment.

In the given scenario, the absence of breathing, absent radial pulse, prolonged capillary refill, and unresponsiveness indicate a critical condition with no signs of life. Therefore, a black tag would be assigned to this individual.

A. Melena B. Decreased vision C. Pancytopenia D. Hyperglycemia

Correct Answer is C

Explanation

Pancytopenia refers to a decrease in all three major blood cell types: red blood cells (anemia), white blood cells (leukopenia), and platelets (thrombocytopenia). It is a potentially serious side effect that can lead to increased susceptibility to infections, anemia-related symptoms (fatigue, weakness), and an increased risk of bleeding. Prompt reporting is necessary for further

evaluation and appropriate management.

While melena (dark, tarry stools) is a concerning side effect, it typically indicates gastrointestinal bleeding, which should also be reported promptly but may not require immediate action unless the bleeding is severe or accompanied by other symptoms.

Decreased vision can be a side effect of certain medications, including NSAIDs, but it does not usually require immediate reporting unless it is severe or rapidly progressive. Hyperglycemia (high blood sugar) can occur with NSAID therapy, especially in individuals with preexisting diabetes or impaired glucose tolerance. While it should be monitored and managed appropriately, it does not typically require immediate reporting unless it is extremely high or associated with other concerning symptoms.

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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?

Nursing Test Bank

Naxlex Comprehensive Predictor Exams

While triaging the wounded from a disaster, you note that one of the wounded is not breathing, radial pulse is absent, capillary refill >2 seconds, and does not respond to your commands. What color tag is assigned?

Correct Answer is D

Explanation

A client with systemic lupus erythematosus (SLE) is receiving nonsteroidal anti- inflammatory drug (NSAID) therapy. Which side effect of NSAID therapy should the nurse immediately report to the health care provider?

Correct Answer is C

Explanation

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