The most appropriate next step in management is to increase the pantoprazole to twice daily. This patient has classic symptoms of gastroesophageal reflux disease (GERD), with heartburn and a sour taste in his mouth. Once-daily proton pump inhibitor (PPI) therapy has significantly improved his symptoms, but he still has breakthrough symptoms at night. Patients with no alarm symptoms (dysphagia, unintentional weight loss, hematemesis, or melena) and a partial response to PPI therapy should have their dose increased to twice daily. Genetic variation in rates of drug metabolism, including PPIs, may decrease effectiveness in some populations (especially white patients), providing a rationale for twice-daily dosing for some patients. Before drug dose escalation, adherence and correct administration (30 to 60 minutes before a meal) should be confirmed. When adequate symptom relief is obtained, it is reasonable to decrease to the lowest effective dose or even stop therapy.

Prokinetic medications such as metoclopramide have no role in the therapy of GERD. Tardive dyskinesia is a serious complication of metoclopramide therapy, is more common in women, occurs with increased frequency with prolonged use, and may be irreversible.

This patient's symptoms are improving with medical therapy, so upper endoscopy is not necessary at this point. Upper endoscopy would be warranted if this patient's symptoms do not improve with twice-daily PPI therapy.

There are no convincing data to suggest that one PPI is superior to another in the treatment of uncomplicated GERD. Increasing the dose of the current PPI is more likely to be beneficial than is switching to another PPI such as omeprazole.