A 50-kg 15-year-old female patient presents to the emergency department 6 hours after ingesting 100 ferrous sulfate tablets, each containing 325 mg. A pregnancy test is negative, and flat plate radiography of the abdomen demonstrates many tablets in the stomach and throughout the small intestine. The patient is intermittently vomiting, with no tablets recovered in the emesis. The patient is otherwise asymptomatic and stable. Which of the following forms of gastrointestinal decontamination should be recommended?