Intravenous erythromycin accelerates gastric emptying in patients with gastroparesis. Its prokinetic action is explained by agonism at which receptor?

• A Muscarinic M3 receptor
• B Gastrin receptor (CCK-B)
• C 5-HT3 receptor
• D Motilin receptor ✓

Explanation

Erythromycin is a motilin receptor agonist. Motilin is the peptide released during fasting that initiates migrating motor complex phase III contractions, so erythromycin mimics these high-amplitude gastric contractions and speeds gastric emptying. This effect occurs at sub-antibiotic doses. Metoclopramide and domperidone act through dopamine A2 antagonism, and cisapride acted through 5-HT4 agonism, none of which involves the motilin pathway.

Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.