Proton pump inhibitors (PPIs) irreversibly block the H+/K+ ATPase (proton pump) on the luminal surface of gastric parietal cells, reducing basal and stimulated acid secretion by 90-95%. PPIs are the most potent acid-suppressing agents and are appropriate for: GERD (short-course 4-8 weeks for mild; maintenance for erosive esophagitis, Barrett's), peptic ulcer disease (with H. pylori eradication or NSAID-induced ulcer healing), Zollinger-Ellison syndrome (pathological hypersecretion), GI bleeding prophylaxis in high-risk ICU patients, and eosinophilic esophagitis. However, PPIs are among the most overprescribed medications: up to 70% of PPI prescriptions lack a clear guideline-based indication, and many patients remain on PPIs indefinitely without reassessment. Long-term PPI risks include: Clostridioides difficile infection (2-3x increased risk — acid suppression allows C. diff spore germination), hip fractures and osteoporosis (impaired calcium absorption), hypomagnesemia (life-threatening in severe cases), community-acquired pneumonia, chronic kidney disease (interstitial nephritis), vitamin B12 deficiency, and fundic gland polyps (benign but concerning). The NP practices PPI stewardship: use the lowest effective dose for the shortest appropriate duration, attempt step-down to H2RA (famotidine) for patients without strong indications for long-term PPI, and counsel on...