How vomiting occurs by emetics

      In general people think vomiting is one of the disease but it’s not a disease it is a symptom of various conditions like  Overeating (poor digestion), Food poisoning, Motion sickness, Morning sickness etc., Before vomiting you can feel nausea (uneasiness), Nausea is a sensation of vomiting or uneasiness and discomfort of gastric mucosa (mucous membrane). 


How does the vomiting occurs

  Vomiting occurs due to stimulation of vomiting (emetic) centre, It is situated in medulla oblongata of brain. Multiple pathways are responsible for produce vomiting, In that Chemoreceptor trigger zone (CTZ) located in postrema and Nucleus tractus solitarius are most relay areas for produce vomiting.CTZ and NTS activates a variety of receptors examples: histamine H1, dopamine D2, serotonin 5-HT3, cholinergic M and opioid. These receptors are relay the vomiting(emetic) signals. 


    Emetics are the drugs which are responsible for produce vomiting by stimulating Vomiting centre by chemoreceptor trigger zone(CTZ) or Nucleus tractus solitarius(NTS). Generaly emetics are mainly used in the treatment of poisoning. Poisoning is caused by ingestion(Intake) of poisonous or toxic substances. Emetics must be taken carefully with proper therapeutic drug monitoring, These are used when gastric lavage is not possible conditions. Unnecessary or over usage of emetics can lead to severe emesis, convulsions dehydration etc…Emetics are classified into three types based on action
  • Centrally acting emetics : Apomorphine
  • Peripherally acting emetics : Copper sulphate, Potassium antimony tartarate 
  • Both centrally and peripherally acting emetics: Ipecacuanha syrup
                                     Image result for ipecac

  1. Apomorphine – acts as dopaminergic agonist on the Chemoreceptor trigger zone then CTZ activates the vomiting centre that leads to produce vomiting. Apomorphine is a semi synthetic derivative of morphine. Apomorphine is administered through Intramuscular or subcutaneous injection but do nor take through Oral route, Because by oral route large dose is required, slow drug action.
  2. Ipecacuanha syrup is obtained from dried root of Cephaelis ipecacuanha it contains emtine which is responsible for irritating gastric mucosa as well as stimulating the CTZ. Dose of drugs is based on age of the patient.
  3. Copper sulpahte, potassium antimony tartarate and Hydrogen peroxide are the synthetic derivative inorganic substances. 
  4. Potassium antimony tartarate: It is prepared by mixing of potassium acid tartarate and antimony trioxide in the ratio of 5:6. By adding two compounds form the fine paste. This fine paste kept aside for 24 hours and then add boiled water to paste with constant stirring for 15 minutes. The hot liquid is filtered and crystallized. It is a peripherally acting emetic.
  5. Copper sulphate: It is prepared by treating of ,copper with diluted sulphuric acid (H2SO4) in the .presence of air. The resulting solution is filtered, evaporated and finally crystallized. It is also used as antidote for  phosphorous poisoning. it is peripherally acting emetic.
        Emesis is induced by emetics and these are preferred during emergency conditions like poisoning when a person ingests poisonous substances either accidentally or suicide cases.

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