A client frequently takes diphenhydramine (Benadryl) to alleviate his upper respiratory symptoms associated with allergies. Which of the following mechanism of actions applies to diphenhydramine (Benadryl)?
stimulates effects of histamine by occupying all H receptor sites.
blocks effects of histamine by competing and occupying H1 receptor sites.
blocks effects of histamine by competing and occupying H2 receptor sites.
stimulates effects of histamine by increasing amount of H2 receptor sites.
The Correct Answer is B
A. Stimulates effects of histamine by occupying all H receptor sites: This statement inaccurately describes the action of diphenhydramine. Instead of stimulating histamine effects, diphenhydramine actually blocks them, particularly at H1 receptors, which are involved in allergic responses.
B. Blocks effects of histamine by competing and occupying H1 receptor sites: This accurately describes the mechanism of action of diphenhydramine. As an antihistamine, it competes with histamine for binding to H1 receptor sites, effectively reducing symptoms of allergies, such as sneezing, itching, and nasal congestion.
C. Blocks effects of histamine by competing and occupying H2 receptor sites: This option is incorrect because H2 receptor antagonists are used primarily to reduce gastric acid secretion, not to treat allergic reactions. Diphenhydramine specifically targets H1 receptors, not H2 receptors.
D. Stimulates effects of histamine by increasing the amount of H2 receptor sites: This statement is also incorrect. Diphenhydramine does not stimulate histamine activity or increase receptor sites. Instead, it functions to inhibit the action of histamine at H1 receptors, which is fundamental in alleviating allergy symptoms.
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View Related questions
Correct Answer is A
Explanation
A. Tachycardia: Theophylline can stimulate the heart, leading to an increase in heart rate. Tachycardia is a common adverse effect associated with theophylline use, and it is essential for the client to be aware of this potential side effect, especially if they have underlying heart conditions.
B. Constipation: While gastrointestinal side effects can occur with theophylline, constipation is not a primary or common adverse effect. Theophylline may actually lead to gastrointestinal upset or increased gastric acid production rather than causing constipation.
C. Drowsiness: Theophylline typically does not cause drowsiness. In fact, it is more likely to
cause restlessness or insomnia, as it is a stimulant. Thus, advising the client about drowsiness is not relevant in this case.
D. Oliguria: Oliguria (reduced urine output) is not a common adverse effect of theophylline. Theophylline can affect kidney function indirectly but does not typically present as oliguria. Monitoring for any renal changes is essential, but oliguria is not a primary concern.
Correct Answer is C
Explanation
A. Inhibits the production of leukotrienes and histamine, preventing further asthma attacks: This statement is misleading. Omalizumab does not directly inhibit the production of leukotrienes or histamine; rather, it works by targeting IgE, which is involved in the allergic response.
B. Inhibits mast cells from releasing histamine, preventing further asthma attacks: While omalizumab does reduce the overall allergic response, it does so by binding to IgE rather than directly inhibiting mast cell activity. Therefore, this description does not accurately represent its primary mechanism of action.
C. Selectively binds to IgE, reducing allergic mediators and asthma attacks: This statement correctly describes the mechanism of action of omalizumab. By binding to immunoglobulin E (IgE), omalizumab prevents IgE from attaching to mast cells and basophils, thus reducing the release of allergic mediators that contribute to asthma attacks.
D. Stimulates alpha-adrenergic receptors to assist in reduction of allergic-related symptoms: This statement is incorrect. Omalizumab does not stimulate alpha-adrenergic receptors; such action is associated with certain bronchodilators. Omalizumab specifically targets IgE to mitigate allergic responses.