Emetics an anti-emetics Flashcards
Which neurotransmitters are responsible for controlling vomiting
- Acetylcholine
- histamine
- 5- hydroxy tryptamine (Serotonin)
- dopamine
What are the contraindications of using emetics
- Unconscious patient- risk of aspiration
- corrosive and caustic poisoning further damage to esophageal lining
- poisoning do to CNS stimulants - risk of seizures
- kerosine poisoning aspiration may occur
Classify anti-emetics
- 5HT3 receptor antagonist
- prokinetic agents
- anti-histamines
- anti-cholinergics
- neuroleptics
- neurokinin NK1 Receptor antagonist
- cannabinoids
- adjuvant antiemetics
a) glucocorticoids
b) benzodiazepines
Name 5HT3 receptor antagonist
- Ondansetron
- Granisteton
- Dolasteron
- Palonosetron
- Ramosetron
Name pro kinetic agents used as anti emetics 
- Metoclopramide
- domperidone
Name antihistamines used as anti-emetics
- Dimenhydrinate
- diphenhydramine
- cyclizine
- meclizine
- hydroxyzine
- promethazine
- doxylamine
- cinnarizine
Name anticholinergic drugs used as an anti-emetics
- Scopolamine
- dicyclomine
Name neuroleptics used as anti-emetics
- Chlorpromazine
- fluphenazine
- prochlorperazine
- haloperidol
Name neurokinins Used as an anti-emetics
- aprepitant
- Fosaprepatent
Name a cannabinoid used as an anti-emetic
- Dronabinol
- Nabilone
Name glucocorticoids and benzodiazepines used as an anti-emetics
Glucocorticoids
1. BetaMethasone
2. dexamethasone
3. Methylprednisolone
Benzodiazepines
1. lorazepam
2. alprazolam
3. Diazepam
What is the mechanism of action of 5-HT3 receptor antagonist
- Blocks Vagal afferents in the gut
- Blocks impulses to chemoreceptor trigger zone (CTZ) and STN in the solitary tract nucleus
What are the uses of 5HT3 antagonist
- Prevention and treatment of chemotherapy induced nausea and vomiting
- effective in hyper emesis of pregnancy, postoperative and post radiation vomiting, drug induced vomiting
- Ramosteron can be used in irritable bowel syndrome
What are the adverse effects of 5HT3 Antagonist
- Headache
- dizziness
- diarrhoea
What are the adverse effects of anti-cholinergics
- Sedation
- dryness of mouth
- blurred vision
- urinary retention
What are the adverse effects of prokinetic drugs
- Drowsiness, dizziness, diarrhoea
- acute dystonia‘s
- other extrapyramidal symptoms dryness of mouth
- Gynaecomastia
- galactorrhoea
- menstrual irregularities
What are the adverse effects of cannabinoids
- Sedation
- dysphoria
- hallucinations
- drug dependence
- Central sympathomimetic effects
- Disorientation
 What are the adverse effects of glucocorticoids used as an anti-emetics
Metabolic disturbances
Name a D2 receptor antagonist that is used as an anti-emetic
Metoclopramide
What is the mechanism of action of metoclopramide
- D2 blockage in CTZ
- Enhances the rate of gastric and duodenal emptying
- enhances release of acetylcholine from myenteric Neurons
What is the effect of metal copper mine in the upper G.I. tract
- Increase in tone of lower oesophageal Sphincter
- increase in tone and amplitude of antral contractions
- Relaxation of pyloric sphincter
- increase in peristalsis of small intestine
It does not have any significant effect on motility of colon
What are the uses of metoclopramide
- As an anti-Emetic
- Gastro-oesophageal flux disease GERD
- Alleviate symptoms associated with gastric stasis in patients with diabetes, post operative or idopathic Gastroparesis
- To stimulate gastric emptying during G.I. radiological procedures and also before general anaesthesia and emergency surgeries.
- Treatment of intractable hiccoughs
What are the drug interactions of metoclopramide
- With diazepam: accelerate its absorption
- with digoxin reduces its absorption
- With levodopa: since it is a D2 blocker, it interferes with the anti-Parkinson effects of levodopa
Why is domperidone preferred over metoclopramide
- Domperidone is preferred anti-emetic in children as it rarely produces ESP
- In patients using levodopa or bromocriptine, it doesn’t affect the anti-Parkinson’s effect because they poorly cross the blood brain barrier

