In a patient with H. pylori infection experiencing persistent symptoms and red flags despite compliance with medication for 2 weeks, what is the next appropriate step?

In a patient with H. pylori infection who continues to exhibit persistent symptoms along with red flags after two weeks of prescribed medication, the most appropriate next step is endoscopy to investigate potential complications such as ulcers or malignancy.

The presence of persistent symptoms alongside red flags—including signs such as significant weight loss, anemia, or gastrointestinal bleeding—raises concern for more serious underlying conditions. Endoscopy allows direct visualization of the gastric mucosa and the esophagus, enabling the clinician to identify ulcers, perform biopsies if indicated, and assess for malignancies. It is a critical diagnostic tool in this context to ensure that treatable conditions are not overlooked.

Other options like repeating antibiotics or initiating proton pump inhibitors might not adequately address the need for thorough evaluation given the patient's concerning symptoms. Scheduling a follow-up after a set period without further investigation would delay necessary interventions, potentially leading to poorer outcomes if a serious condition is present. Therefore, in the setting of continued symptoms and red flags, endoscopy is the most prudent and effective next step.