ANTIEMETICS USED IN PREGNANCY
by Winna Pei Jia Low
1. METOCLOPRAMIDE
1.1. MOA: Block dopamine receptors in high dose, block serotonin receptors in chemoreceptor trigger zone, enhance tissue response to Ach and increase gastric emptying, increase lower esophageal sphincter tone.
2. PYRIDOXINE (VITAMIN B6)
2.1. MOA: Unknown but indicated for emesis in pregnancy
3. CHLORPROMAZINE
3.1. MOA: Dopamine D2 receptor antagonist and blocks the postsynaptic dopamine receptor in the mesolimbic system of the brain to prevent emesis
4. PROMETHAZINE
4.1. MOA: Compete with histamine for H1 receptors to prevent histamine from binding and stimulating the cells, block Ach actions (anticholinergic), combination of actions to decrease stimulation of emesis center.
