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","C"]
Explanation
A) Decongestants: These medications are primarily used to relieve nasal congestion associated with upper respiratory conditions such as allergic rhinitis and the common cold. They work by constricting blood vessels in the nasal passages, thereby reducing swelling and congestion. Common examples include pseudoephedrine and phenylephrine.
B) H2 Antagonist: H2 antagonists are primarily used to reduce gastric acid secretion and treat conditions such as peptic ulcers and gastroesophageal reflux disease (GERD). They are not indicated for upper respiratory conditions, so this option does not apply.
C) H1 Antagonist: H1 antagonists, or antihistamines, are used to alleviate symptoms of allergies, hay fever, and other upper respiratory conditions by blocking the effects of histamine. This class includes both first-generation antihistamines (like diphenhydramine) and second-generation antihistamines (like cetirizine), making them relevant for upper respiratory issues.
D) Long-Acting Beta Agonist (LABA): LABAs are primarily used for the management of asthma and chronic obstructive pulmonary disease (COPD), targeting the lower respiratory tract. They are not typically used for upper respiratory conditions, so this option does not apply.
E) Short Acting Beta Agonist (SABA): SABAs, such as albuterol, are primarily used for acute asthma attacks and bronchospasm in conditions like COPD. They act on the lower respiratory tract and are not indicated for upper respiratory conditions.
F) Mast Cell Stabilizers: These medications are used to prevent allergic reactions and asthma symptoms by stabilizing mast cells and preventing the release of histamine and other inflammatory mediators. While they may have a role in allergic rhinitis, they are not the primary treatment for upper respiratory tract conditions, making this option less applicable compared to decongestants and H1 antagonists.
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.