H2 Receptor Antagonist Antacids (H2RA): Pharmacology Made Easy & Clinically Relevant

H₂ receptor antagonists like famotidine and cimetidine have been around for decades, but they still play an important role in managing GERD, dyspepsia, ulcers, and even acute GI bleeding. In this episode, Dr. Busti reviews the history, pharmacology, and clinical relevance of this class, including the withdrawal of ranitidine.You’ll learn how H₂ blockers fit into the larger category of antacid therapy, why they’re effective for mild cases but limited in long-term control, and how tolerance can reduce effectiveness. Cimetidine’s drug interaction profile is explored in detail, including CYP450 effects and alcohol metabolism. Practical dosing considerations are highlighted, such as twice-daily administration, renal adjustments, and limits on self-directed OTC use.Whether you’re a student preparing for boards, a resident managing patients at the bedside, or a clinician counseling someone who self-treats, this review gives you the “why” behind the pharmacology to guide better decisions.Find this episode's downloads at https://www.thisiswhy.health/topics/pharmacology-review-h2-receptor-antagonists-h2raDisclaimer: This content is for educational purposes only and is not intended to provide medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have heard in this content.