Problem:
A patient is diagnosed with moderate gastritis following an upper endoscopy. A gastric biopsy test from the procedure confirms the presence of Helicobacter pylori. The primary care provider orders lansoprazole before breakfast once daily, clarithromycin, and amoxicillin. After 14 days of treatment, H. pylori is still no longer present, but the patient reports only a mild reduction in GI symptoms. The provider should order: