Antihistamines Lecture Flashcards

These flashcards cover key concepts related to antihistamines, histamine functions, receptor types, and differences between 1st and 2nd generation antihistamines.

What is histamine and where is it found?

Histamine is an autocoid present in virtually all tissues, formed by histidine and acts as a local hormone.

What are histamine receptors?

Histamine receptors are G-protein coupled receptors, including H1, H2, H3, and H4.

What are the main effects of H1 receptor antagonists?

H1 receptor antagonists are primarily used to treat allergic reactions, reduce nasal secretions, and prevent motion sickness.

What are the main functions of H2 receptors?

H2 receptors primarily regulate gastric acid secretion in the stomach.

What are 1st generation antihistamines known for?

1st generation antihistamines are known to cross the blood-brain barrier, causing sedation and having anticholinergic side effects.

What is an example of a 1st generation antihistamine?

Examples include Hydroxyzine, Promethazine, and Diphenhydramine.

What are the differences between H1 and H2 receptor antagonists?

H1 antagonists primarily address allergic reactions and hypersensitivity, while H2 antagonists target gastric acid secretion and conditions like GERD and peptic ulcers.

What adverse effects can result from 1st generation antihistamines?

Adverse effects include sedation, dry mouth, urinary retention, blurred vision, and paradoxical hyperactivity in children.

How are 2nd generation antihistamines different from 1st generation?

2nd generation antihistamines are less sedating and less likely to cross the blood-brain barrier.

What is the role of proton pump inhibitors (PPIs) compared to H2 antagonists?

PPIs are more effective than H2 antagonists for reducing gastric acid secretion but have a delayed onset of action.