Metaclopramide all are true except -
Ans. is 'b' i.e., D2-agonist o Metaclopramide is D2-antagonist (not agonist).Metoclopramideo Metoclopramide is aprokinetic drug -Promotes gastrointestinal transit and speed gastric emptying by enhancing coordinated propulsive motility.o It has more prominent effect on upper GIT - increases gastric peristalsis, while relaxing the pylorus and the first part of duodenum - speed gastric emptying. Tone of lower esophageal sphincter (LES) is increased and gastroesophageal reflux opposed.o It has less prominent effect on lower GIT - increases intestinal motility to some extent, but has no significant action on colonic motility,o Metoclopramide is an effective antiemetic.o Mechanism of action.1. 5-HT4 agonism - stimulation of 5-HT4 receptor in GIT enhances the release of ACH from myenteric plexus - Main prokinetic action of metoclopropamide is due to this action.2. D2 antagonism - Blockade of D2 receptor in CTZ is mainly responsible for antiemetic effect. D2 receptor blockade in GIT is responsible for some prokinetic action also.3. 5-HT3 antagonism - At higher concentration.o Uses - As an antiemetic, as a gastrokinetic in GERD, in dyspepsia.o Adverse effects - Sedation, dizziness, loose stools, muscle dystonia (especially in children) are the main side effects. D2 - blocking action may cause extrapyramidal symptoms (Akathsia, Parkinsonism) and hyperprolactinemia (galactorrhea, gynacomastia).
Increase gastric emptying
D2-agonist
Acts on CTZ
Long term use can cause parkinsonism, galactorrhoea and gynaecomastia
G.I.T