Which H2 blocker is specifically known for its rapid onset of action?

Ranitidine is specifically known for its rapid onset of action among the H2 blockers. This characteristic makes it particularly useful in clinical situations where quick symptom relief from conditions such as gastroesophageal reflux disease (GERD) or peptic ulcers is necessary. Ranitidine can be administered orally or intravenously, with intravenous administration providing even faster relief since it bypasses the gastrointestinal absorption phase.

In comparison, other H2 blockers, while effective, typically have a slightly longer onset time. Cimetidine, for instance, was among the first H2 blockers but is less commonly used today due to various side effects and interactions. Famotidine is another effective H2 blocker, but its onset might not match the rapidity of ranitidine. Omeprazole, on the other hand, is a proton pump inhibitor rather than an H2 blocker, and it works differently by blocking gastric acid production more potently, but it does not act as quickly as ranitidine when immediate effects are required. Thus, ranitidine's quicker action makes it the go-to choice when swift relief is needed for acid-related conditions.