How do H2 receptor antagonists differ from proton pump inhibitors in terms of onset and duration, and when might each be preferred?

• A. H2 blockers have slower onset but longer duration; PPIs have rapid onset.
• B. H2 blockers have quicker onset but shorter duration; PPIs provide stronger, longer suppression; H2 useful for mild symptoms; PPIs for chronic or erosive disease.
• C. PPIs are always first-line due to faster onset.
• D. H2 blockers cure GERD.

Answer: (B)

H2 receptor antagonists act quickly to reduce acid production but their effect is temporary, while proton pump inhibitors produce stronger, longer-lasting acid suppression once they take effect. H2 blockers begin relieving symptoms relatively fast, often within an hour, and last only a portion of the day, making them useful for on-demand or intermittent relief. In contrast, PPIs require a few days to achieve their full effect because they permanently inhibit the proton pumps in parietal cells and stop new pumps from functioning, so the acid-suppressing effect lasts longer and is more powerful.

Because of this, H2 blockers are often preferred for mild, infrequent symptoms or when quick relief is desired, whereas PPIs are favored for chronic GERD, erosive esophagitis, or ulcers where ongoing, substantial acid suppression is needed.