H2 receptor antagonists (H2RAs)
- Moderate histamine-mediated acid suppression
- GERD/dyspepsia/ulcer niches
- Faster onset but weaker than PPIs
- Useful for intermittent/nocturnal symptoms
- Tachyphylaxis develops with continuous use
- Famotidine is the cleanest common option
- Cimetidine has many CYP/endocrine effects
Class at a glance
- Moderate histamine-mediated acid suppression
Pharmacology
- Cimetidine has many CYP/endocrine effects
Practical pearls
- GERD/dyspepsia/ulcer niches
- Faster onset but weaker than PPIs
Clinical role
- Useful for intermittent/nocturnal symptoms
- Tachyphylaxis develops with continuous use
- Famotidine is the cleanest common option
Self-check
- When are H2 receptor antagonists (H2RAs) especially useful?
Intermittent/nocturnal symptoms. - What distinguishes Cimetidine?
Many CYP/endocrine effects.
Drugs in this class (3)
H2 receptor antagonists (H2RAs) prescription history
Animated chart of estimated U.S. prescriptions per year, Acid-suppressing meds (1977–2026). H2 blocker highlighted from 1977.
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