Domperidone is a dopamine antagonist medication primarily used to treat nausea, vomiting, heartburn, indigestion, and gastrointestinal motility disorders like gastroparesis by enhancing stomach and intestinal movements. It works peripherally by blocking dopamine D2 and D3 receptors in the gut and chemoreceptor trigger zone, promoting faster gastric emptying without significant central nervous system effects due to limited blood-brain barrier penetration. Additionally, it elevates prolactin levels, aiding lactation in some cases, and is available orally.