Differential Diagnosis for Evening Nausea and Dry Heaving Unresponsive to Ondansetron

Key Diagnostic Considerations

The American Gastroenterological Association suggests that evening predominance with dry heaving indicates gastroparesis or delayed gastric emptying, where food accumulates throughout the day and symptoms worsen in the evening 1
The National Comprehensive Cancer Network recommends considering GERD/Dyspepsia because patients often have difficulty discriminating heartburn from nausea, and evening symptoms can occur when lying down increases reflux 2, 3
Hyperglycemia itself can cause antral hypomotility and delayed gastric emptying, according to the American Gastroenterological Association 1
Electrolyte abnormalities, such as hyponatremia, hypercalcemia, or uremia, should be evaluated as potential metabolic or medication-induced causes, as recommended by the National Comprehensive Cancer Network 2, 3

Gastric emptying scintigraphy is the gold standard for diagnosing gastroparesis, and must be performed for at least 2 hours, according to the American Gastroenterological Association 1
The National Comprehensive Cancer Network recommends a comprehensive metabolic panel to assess electrolytes, renal function, and glucose, as well as hemoglobin A1c if diabetes is suspected 1, 2, 3

The National Comprehensive Cancer Network recommends prochlorperazine 10 mg PO every 6 hours as needed, metoclopramide 10-20 mg PO three times daily, and haloperidol 0.5-1 mg PO every 6-8 hours as first-line additions for antiemetic therapy 3, 4
A scheduled dosing approach, switching to scheduled administration around the clock for one week, then reassessing, is recommended by the National Comprehensive Cancer Network if nausea persists despite as-needed dosing 4