Domperidone(Motilium) is a dopamine blocker and an antidopaminergic reagent. It blocks the action of. It has strong affinities for the D2 and D3 dopamine receptors, which are found in the chemoreceptor trigger zone, located just outside the blood brain barrier, which – among others – regulates nausea and vomiting (area postrema on the floor of the fourth ventricle and rhomboid fossa).