The document discusses emetics and vomiting. It defines emesis as vomiting and describes the vomiting center in the medulla oblongata. It then discusses the emetic response process and various triggering agents and neurotransmitters involved. The document lists some common emetics like apomorphine and ipecacuanha, describing their mechanisms and uses. It also discusses home remedies for inducing vomiting and notes when not to use emetics. Finally, it covers different categories of antiemetics and some examples of common antiemetic drugs.

1. Emetics
Dr Ibanda Hood

2. • Emesis is vomiting. It is characterised by forceful elimination of gastric
content through the mouth.
• In the medulla oblongata, vomiting center or emetic center are situated, that region
is known as Area postrema. In the area postrema Chemoreceptor Trigger Zone
(CTZ) and Nucleus Tractus Solitarius (NTS) is also present.
Emetic Response: This involves relaxation of fundus, body of stomach and also the
oesophageal sphincter and oesophagus – but contraction of pylorus and duodenum –
then rhythmic contraction of diaphragm and abdominal muscles - expulsion via mouth
Centre: Medulla Oblongata
The Relay Centers are chemoreceptor trigger zone (CTZ) and nucleus tractus Solitarius
(NTS)
Definitions and the process of vomiting

3. • Afferent impulses Are from the GIT, throat and other viscera
• The Triggering agents: Blood borne drugs, mediators, hormones and
toxins etc. – clinically cytotoxic drugs and radiation
• The neurotransmitter are: 5-HT (enterochromaffin cells) – via 5HT3
receptor of ENS – to vagal and spinal visceral neurones ----- to CTZ
and NTS and Spilling of 5-HT due to massive release – acts on CTZ

4. Mediators of vomiting: H1, D2, 5HT3, Muscarinic M and opioid μ etc. They are
expressed in CTZ and NTS
Vestibular apparatus: generates impulses when Body equilibrium disturbed or by
Ototoxic drugs. The impluses are Mainly relayed by cerebellum to vomiting centre
– Muscarinic and H1 receptors
Directly in higher centres: Bad smell, ghastly sight, pain, fear etc. – drug cisplatin

5. Emetics
• Apomorphine
• Ipecacuanha
• Other home remedies

6. Apomorphine
• Apomorphine is the synthetic derivative of the morphine. It acts as a
dopaminergic agonist on CTZ. Apomorphin is administered in the
muscles(IM) or Subcutaneous(SC) in a dose of 6mg. The patient
vomits in 5 minutes.
• Side effects: Parkinsonism

7. Ipecacuanha
• Ipecacuanha : Ipecacuanha drug is a part of the dried root of
Cephaelis ipecacuanha contains emetine. It acts by irritating gastric
mucosa and as well as through CTZ.
• That drug is used as a syrup ipeca. The dose of Ipecacuanha in an
adult is 15-30ml, in children 10-15ml and 5ml in the infant. It takes 15
min or more for the action.

8. Home remedies for emesis
Salt + water
You mix 1 spoon of salt with 1 pint warm water; this solution has mild
emetic action.
Mustard Seed
Mix 1 spoon of mustard seed powder with ½ pint of water.
Strong coffee: this is a stimulant of vomiting if a person has narcotic
poisoning.

9. When not to give emetics
• When patient has ingested a corrosive agent e.g. acid or alkali
• If the patient has poisoning with a CNS stimulant
• If the patient is unconscious
• If the patient has morphine or phenothiazine poisoning.

10. Antiemetics

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Antiemetics
Five categories of antiemetics
1.Anticholinergics
2.Antihistamines
3.Neuroleptic agents
4.Prokinetic agents
5.Serotonin blockers

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Antiemetics
Five categories of antiemetics
1.Anticholinergics
2.Antihistamines
3.Neuroleptic agents
4.Prokinetic agents
5.Serotonin blockers

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Anticholinergics and Antihistamines
• Anticholinergics
• Bind to and block acetylcholine receptors
• Prevent nausea stimuli from being transmitted
• Antihistamines
• Block H2 receptors
• Prevent cholinergic stimulation

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Neuroleptic and Prokinetic Agents
• Neuroleptic agents
• Bind to the dopamine receptors and block action
• Limit dopamine activity
• Prokinetic agents
• Block dopamine
• Stimulate acetylcholine to increase gastric emptying

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Serotonin Blockers
• Block serotonin receptors in the gastrointestinal
tract
• Block serotonin receptors in the central nervous
system (emetic center)
• Used often when antineoplastic agents are being given

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Anticholinergics and Antihistamines
• Anticholinergics
• Scopolamine (Trans Scop)
• Antihistamines
• Promethazine (Phenergan)
• Meclizine (Antivert)

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Emetics and Antiemetics
• Neuroleptic agents
• Chlorpromazine (Thorazine)
• Prokinetic agents
• Metoclopramide (Reglan)
• Serotonin blockers
• Ondansetron (Zofran)

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Side Effects and Adverse Effects
• General
• Dizziness
• Drowsiness
• Dry mouth
• Headache

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Nursing Process
 Assessment
 Thorough history and physical
 Plan
 Use proper route
 Implementation
 Safely administer medication
 Evaluation
 Are the nausea and vomiting gone?