About cinnarizinepiperazines derivative, antihistamine, antivertigo.mechanism of action of cinnarizinecinnarizine is a specific competitive h1 receptor antagonist. it suppresses the vestibular end organ receptors and thus inhibits the activation of central cholinergic receptors. cinnarizine inhibits contractions of vascular smooth muscles by inhibiting the calcium channels preferably in the arterial smooth muscle.about domperidoneantidopaminergic, motility stimulant,piperidine derivative, antiemetic, anti-vertigo.mechanism of action of domperidonedomperidone is a potent dopamine receptor antagonist. it acts centrally and blocks the dopamine receptor in the chemoreceptor trigger zone and produces antiemetic effect. domperidone acts peripherally in the gastrointestinal system and increases oesophageal peristalsis, oesophageal sphincter pressure and gastric motility. these all facilitates gastric emptying. domperidone is used in migraine to relieve nausea and vomiting. a