Drug of choice for Zollinger-Ellison syndrome ?
**Core Concept**
Zollinger-Ellison syndrome is a rare disorder characterized by excessive gastric acid secretion due to high levels of gastrin, often caused by a gastrinoma, a type of neuroendocrine tumor. The condition leads to severe peptic ulcers, diarrhea, and abdominal pain.
**Why the Correct Answer is Right**
The drug of choice for Zollinger-Ellison syndrome is a proton pump inhibitor (PPI) that effectively reduces gastric acid secretion. PPIs, such as omeprazole, work by irreversibly inhibiting the H+/K+ ATPase enzyme system at the secretory surface of gastric parietal cells. This results in a significant decrease in gastric acid production, providing relief from symptoms.
**Why Each Wrong Option is Incorrect**
**Option A:** H2 receptor antagonists, such as ranitidine, are not the first-line treatment for Zollinger-Ellison syndrome as they only partially reduce gastric acid secretion.
**Option B:** Antacids and histamine-2 (H2) blockers are inadequate for controlling the high acid production seen in Zollinger-Ellison syndrome.
**Option C:** Prokinetics, such as metoclopramide, are not effective in reducing gastric acid secretion and are not the primary treatment for Zollinger-Ellison syndrome.
**Clinical Pearl / High-Yield Fact**
PPIs are the preferred treatment for Zollinger-Ellison syndrome due to their potent and long-lasting inhibition of gastric acid secretion.
**Correct Answer: C. Omeprazole**