C, Capsules; HF, heart failure; HTN, hypertension; I, injection; OS, oral solution; S, suspension; T, tablets. Gastroesophageal Reflux Disease (GERD), Peptic Ulcer Disease (PUD) GERD is the most common GI condition encountered in the outpatient setting. Symptoms include heartburn, regurgitation, dyspepsia, chest pain, belching, chronic cough. Drugs that suppress gastric acid are the standard treatment for GERD and include H2 receptor antagonists (H2RAs) and proton pump inhibitors (PPIs). PUD is most commonly caused by Helicobacter pylori infection (other causes include use of nonsteroidal anti-inflammatory drugs [NSAIDs], including aspirin, ibuprofen, and naproxen). H2RAS: Inhibit histamine action at H2 receptors on parietal cells, decreasing basal acid secretion and, to a much lesser extent, foodstimulated acid secretion. PPIs: Binds to activated proton pump on the apical membrane of parietal cells, resulting in inhibition of acid secretion into the gastric lumen. H2 -RECEPTOR ANTAGONISTS (H2RAS)