ROLE OF Histamine Type-2 Receptor Antagonists (H2 Blockers)

Histamine type 2 receptor antagonists (H2 blockers) are a class of medications that inhibit histamine-induced gastric acid secretion by competitively blocking H2 receptors located on the parietal cells of the stomach. Introduced in the 1970s, H2 blockers revolutionized the management of acid-related gastrointestinal disorders, such as peptic ulcer disease, gastroesophageal reflux disease (GERD), Zollinger-Ellison syndrome, and functional dyspepsia. By reducing gastric acid output, these agents promote ulcer healing, relieve symptoms of acid reflux, and prevent recurrence of acid-related damage. Commonly used H2 blockers include ranitidine, famotidine, cimetidine, and nizatidine. Although the advent of proton pump inhibitors (PPIs) has shifted clinical preference due to their more potent acid suppression, H2 blockers remain valuable for their rapid onset of action, favorable safety profile, and effectiveness in mild-to-moderate acid-related conditions. Additionally, H2 blockers are useful in nocturnal acid breakthrough and in patients intolerant to PPIs. Ongoing evaluation of safety concerns, particularly regarding long-term use, is essential. This abstract reviews the pharmacological role, therapeutic applications, and clinical relevance of H2 blockers in current medical practice.