Emetics and Antiemetics: A Review

Emetics is a complex reflex coordinated by the vomiting centre in the medulla. The afferent and efferent pathaways which cause vomiting are carried by vagus and sympathetic nerves. Chemo-receptor trigger zone is major sensory relay station, present in the lateral border of the area postrema of medulla oblongata. Afferent stimulation like tactile pharyngeal impulses, abryrinthine disturbances, pain, distyension of viscera, psychology factors, increased intracranial pressure, emetic drugs, radiation therapy, electrolyte disturbances, endocrine disturbances, pregnancy etc, cause ‘emesis’ i.e. Vomiting.