and theophylline. H. pylori infection is the primary risk factor for developing peptic ulcer disease; additional risk factors include the use of certain medications (e.g., NSAIDs, corticosteroids, bisphosphonates, potassium chloride, chemotherapeutic agents), smoking, hypersecretory conditions (e.g., Zollinger-Ellison syndrome [ZES]), chronic pulmonary disease, and chronic renal disease. Risk for gastric cancer is increased in individuals aged 55 years or older.