Two classes of drugs may be more effective than others for the treatment of gastroparesis, though the overall quality of evidence remains low to moderate and additional data are needed, according to a new report. Oral dopamine antagonists and tachykinin-1 antagonists appear superior to placebo. Only one drug, the dopamine antagonist metoclopramide, has US Food and Drug Administration approval for the treatment of gastroparesis (Gastroparesis is a chronic disorder which means delayed stomach emptying without a blockage).