Which drug acts by stimulating motilin receptors?

Erythromycin is known to act as a motilin receptor agonist, which is a significant mechanism for its gastrointestinal motility effects. Motilin is a hormone that plays a crucial role in stimulating gastrointestinal motility, particularly during the fasting state, by initiating phase III of the migrating motor complex (MMC).

When erythromycin mimics motilin's action by binding to motilin receptors in the gut, it enhances peristalsis and promotes gastric emptying. This property is particularly useful in clinical settings to treat certain types of gastroparesis or to facilitate gastric emptying before endoscopic procedures. Erythromycin's ability to stimulate motilin receptors distinguishes it from other prokinetic agents that work via different mechanisms.

Cisapride and metoclopramide, while also used to enhance gastrointestinal motility, do so through different pathways. Cisapride primarily works by enhancing the release of acetylcholine from the myenteric plexus and has serotonergic properties, while metoclopramide acts primarily as a dopamine antagonist, leading to increased motility in the upper gastrointestinal tract without directly stimulating motilin receptors. Domperidone similarly acts as a dopamine antagonist but does not significantly enhance motility in the same manner