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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Correct Answer is A
Explanation
A) Beta-Blockers: The use of beta-blockers is a direct contraindication to albuterol administration. Albuterol is a beta-agonist that works by stimulating beta-2 adrenergic receptors to cause bronchodilation. Beta-blockers can antagonize this effect, potentially leading to increased bronchospasm and worsening asthma symptoms. Therefore, if a client is on beta-blockers, caution must be exercised when administering albuterol.
B) Anticholinergics: Anticholinergics, such as ipratropium, are often used in conjunction with beta-agonists like albuterol to provide synergistic effects in managing asthma. There are no direct contraindications between anticholinergics and albuterol, and they can be used together safely to improve bronchial dilation and mucus clearance.
C) Antihistamines: Antihistamines are not contraindicated with albuterol. While they may be used for managing allergic reactions and symptoms, they do not interfere with the action of beta-agonists. Therefore, a client taking antihistamines can still safely receive albuterol for acute asthma attacks.
D) Glucocorticoids: Glucocorticoids, such as prednisone, are often used in asthma management for their anti-inflammatory properties. They are not contraindicated with albuterol; in fact, they are commonly used together in asthma treatment plans. Glucocorticoids help to reduce airway inflammation, while albuterol provides quick relief from bronchospasm.
Correct Answer is A
Explanation
A) Liver injury: Zafirlukast (Accolate) has been associated with the risk of liver injury. It is important for clients to be informed about this potential adverse effect, as it may require monitoring of liver function tests during treatment. Symptoms of liver injury, such as jaundice, dark urine, or severe fatigue, should prompt clients to seek medical attention.
B) Bradycardia: Bradycardia is not a commonly associated adverse effect of zafirlukast. This medication primarily works as a leukotriene receptor antagonist and does not typically affect heart rate significantly. Clients should be aware of other more relevant side effects rather than bradycardia.
C) Renal failure: Renal failure is not a known adverse effect of zafirlukast. While kidney function should always be monitored in patients taking various medications, zafirlukast specifically does not have a direct association with renal failure.
D) Bronchoconstriction: While bronchoconstriction is a concern in asthma management, zafirlukast is designed to prevent bronchoconstriction by blocking leukotriene receptors. Therefore, it is not an adverse effect of the medication. In fact, its purpose is to help reduce the incidence of bronchoconstriction and improve asthma control.