Which of the following is a prokinetic drug with no dopamine antagonism?
High-Yield Explanation
PROKINETIC DRUGS ACh is the main excitatory neurotransmitter in the GIT. Cholinergic neurons contain excitatory (5-HT4) as well as inhibitory (5HT3, D2) presynaptic receptors. Thus D2 and 5HT3 antagonists and 5 HT4 agonists will increase the release of ACh and stimulate the GI motility. Metoclopramide possesses central as well as peripheral D2 blocking action. Central D2 blocking action is responsible for its antiemetic effects. Domperidone is a D2 receptor antagonist and cannot cross blood brain barrier. It is mainly used as an antiemetic (less efficacious than metoclopramide) drug and is devoid of extrapyramidal and hyperprolactinemic adverse effects. Cisapride, mosapride, renzapride, prucalopride and tegaserod are 5-HT4 agonistic drugs with no action on D2 receptors (no antiemetic propey). These drugs increase whole GI motility including colon.