H2 Receptor Antagonist Antacids (H2RA): Pharmacology Made Easy & Clinically Relevant
The H2RA are one of several classes of antacids used in the management of gastritis, peptic ulcer disease, GERD, & even allergic reactions. Understanding the why of H2RA's pharmacology makes the application easier.
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In this This Is Why with Dr. Busti pharmacology review, Dr. Busti explores the pharmacology, physiology, and clinical relevance of the H₂ receptor antagonists—a long-standing drug class that remains an important option for managing GERD, dyspepsia, and peptic ulcer disease. Drawing on decades of experience in clinical medicine and academia, he explains how agents like cimetidine, famotidine, and nizatidine work at the cellular level to reduce gastric acid secretion, and how understanding their mechanism, pharmacokinetics, and drug interactions helps clinicians use them safely and effectively.
From bedside use in GERD to adjunctive therapy in anaphylaxis and inpatient acid suppression, this episode connects the why behind H₂ blockers’ continued place in therapy — including when to switch to PPIs or potassium-competitive acid blockers (P-CABs).
Chapter Table of Contents
00:00 Introduction to H2 Receptor Antagonists (H2RA)
00:36 History of Cimetidine, Ranitidine, Famotidine & Nizatidine
01:07 Why H2RAs Still Matter: Clinical Relevance in Modern Practice
02:44 Indications & Therapeutic Uses: GERD, Ulcers, Dyspepsia & More
08:27 Anatomy & Pathophysiology: GERD, Ulcers, Barrett’s, GI Bleeding
16:09 Mechanism of Action: Blocking H2-Mediated Acid Secretion
20:27 OTC Antacids vs H2RAs: Onset, Duration & Clinical Positioning
25:04 Pharmacokinetics & Pharmacodynamics: Acid Suppression Duration, Metabolism & Clinical Impact
29:26 Drug Interactions: CYP Pathways, Binding, and Clinical Impact
30:33 Self-Treatment Pitfalls: Misdiagnosis, Heartburn vs ACS & When to Seek Care
31:52 Treatment Durations: OTC vs Prescription Use, GERD & Ulcer Healing Timelines
#H2blockers #pharmacology #GIpharmacology #medicaleducation
Speaker:
Anthony Busti, MD, PharmD, MSc, FAHA, FNLA, is a licensed healthcare professional and medical educator with over 30 years of experience in clinical practice and academic teaching. He has trained and practiced as a nurse, pharmacist, and physician, bringing a uniquely comprehensive perspective to patient care and medical education.
Dr. Busti is dedicated to advancing evidence-based medicine and helping clinicians understand the underlying “why” behind clinical decisions to improve patient outcomes.
About This Channel:
This content is created by Anthony Busti, MD, PharmD, MSc, FAHA, FNLA, a board-certified physician with training at Johns Hopkins School of Medicine and University of Oxford and a medical educator for healthcare professionals and students. All material is based on current medical literature and evidence-based guidelines that align with principles of evidence-based medicine (EBM) and Evidence-Based Healthcare (EBHC).
Disclaimer:
This content is for educational purposes only and is not medical advice. It does not replace individualized evaluation, diagnosis, or treatment. Always seek the advice of a qualified health provider with questions about a medical condition and never delay care because of educational content.
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