Metoclopramide given as a prokinetic acts primarily by:

• A Blocking 5-HT4 receptors on myenteric neurons to accelerate gut motility
• B Directly stimulating motilin receptors on smooth muscle
• C Inhibiting acetylcholinesterase in the myenteric plexus
• D Antagonising dopamine D2 receptors in the enteric nervous system and CTZ, while also having 5-HT4 agonism ✓

Explanation

Metoclopramide is a dopamine D2 receptor antagonist in the enteric nervous system, removing the inhibitory tone dopamine exerts on acetylcholine release, thereby increasing coordinated gastric and small intestinal contractions. It also has 5-HT4 agonist activity, which further promotes acetylcholine release from myenteric neurons. Its central D2 blockade at the CTZ provides antiemetic effect but also causes extrapyramidal side effects with prolonged use, particularly tardive dyskinesia.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.