A patient is receiving histamine receptor antagonist for peptic ulcers and ask to the nurse about mode of action of histamine receptor antagonist. The best response given by the nursing officer is?

Appeared in: PGIMER Sangrur NO - 2023

Explanation

Histamine-2 (H2) receptor antagonists work by competitively blocking H2 receptors located on the parietal cells of the stomach.
This blockade prevents histamine from stimulating the cells to produce hydrochloric acid (HCl).
The primary therapeutic effect is a significant reduction in both the volume and concentration of gastric acid, which promotes the healing of peptic ulcers.
These drugs are highly selective for H2 receptors and do not affect H1 or H3 receptors.

Option A: This describes the mechanism of anticholinergic drugs. H2 antagonists do not directly decrease the activity of acetylcholine, although they can diminish the acid secretion stimulated by it.
Option C: This action would worsen peptic ulcers. The entire therapeutic goal of using H2 antagonists is to reduce, not increase, gastric acid.
Option D: This is the mechanism of action for prokinetic agents. H2 antagonists do not have a direct effect on gastric motility or peristalsis.

Clinical Relevance

Nursing practice connection: Use the key finding related to Mechanism of action of histamine receptor antagonists to guide bedside assessment, documentation, and the next nursing action.
Patient education is a key nursing role. Explaining the drug's action in simple terms—that it 'turns down the acid pump' in the stomach—can improve adherence and patient understanding.
Monitoring for side effects is crucial. For instance, cimetidine can cause confusion and dizziness, especially in older adults or those with kidney problems. Nurses must assess for these CNS changes.
Timing of administration matters. H2 blockers are often given at bedtime to suppress the natural increase in acid production during the night, promoting ulcer healing.

How to Approach the Question

First, identify the core subject of the question: the mode of action of a specific drug class, 'histamine receptor antagonists', for treating 'peptic ulcers'.
Recall the pathophysiology of peptic ulcers, which involves damage from gastric acid. The goal of treatment is therefore to reduce this acid.
Analyze the drug class name: 'histamine receptor antagonist'. This name itself suggests the drug blocks histamine.
Evaluate each option: Does it relate to blocking histamine or reducing acid? 'Decreases gastric acid secretions' is a direct and logical consequence of blocking a stimulant (histamine) of acid production.
Eliminate other options by linking them to different drug classes: 'Decreases activity of acetylcholine' points to anticholinergics, and 'Increases peristalsis' points to prokinetics.

Concept Tested & Keywords

Q8bosrw0MG0-ElC3lkqo-E

E6 Pharmacology Katzung 16e pp. 1695-1697, 1693-1695

E6 Pharmacology KD Tripathi Essentials 9e Part 2 p. 323-325

Practise the full PGIMER Sangrur NO - 2023

Attempt every question from this paper in a timed mock, then review the full solution for each one.