Please enable JavaScript.
Coggle requires JavaScript to display documents.
Treatment of Nausea and Vomiting (NK1 Receptor Antagonists (Drugs: …
Treatment of Nausea and Vomiting
D2 Receptor Antagonists
Drugs:
Metoclopramide, Domperidone, Prochlorperazine, Droperidol
Mechanism of action:
Blocks action of dopamine on D2 receptors in CTZ
This decreases stimulation of the vomiting centre
Metoclopramide and domperidone also block D2 receptors in the stomach increasing stomach emptying into small intestine
Prochlorperazine and droperidol also block H1 and M1 receptors in vomiting centre
Adverse effects:
Drowsiness, fatigue, movement disorders, galactorrhoea
Domperidone will cause less adverse effects as no BBB penetration
Prochlorperazine will cause more drowsiness (H1 blockage too)
Clinical use:
Nausea and vomiting caused by chemicals
Prochlorperazine also used in vertigo
Metoclopramide and domperidone also used in gastric stasis
5-HT3 Receptor Antagonists
Drugs:
Ondansetron, Dolasetron, Granisetron, Tropisetron, Palonosetron
Mechanism of action:
Blocks serotonin on 5-HT3 receptors in CTZ and vagal afferent nerves
Adverse effects:
Constipation, headache, dizziness
Clinical use:
Nausea caused by chemicals
Often used to prevent nausea and vomiting in chemotherapy, radiotherapy or surgery
NK1 Receptor Antagonists
Drugs:
Aprepitant, Fosaprepitant (aprepitant prodrug)
Mechanism of action:
Blocks the action of substance P on NK-1 receptors in the CTZ and vomiting centre
Adverse effects:
Diarrhoea, fatigue, dizziness, weakness, hiccups
Clinical use:
Prevention (with other anti-emetics) of nausea and vomiting associated with chemotherapy
Drug interactions:
Aprepitant inhibits, induces and is metabolised by CYP3A4 and induces CYP2C9. Any drugs that interact with these enzymes may have increased or decreased therapeutic effects
Corticosteroids
Drugs:
Dexamethasone
Mechanism of action:
Unclear
Thought to inhibit prostaglandin synthesis thus decreasing serotonin turnover in CNS
May release endorphins that elevate mood, improve one's sense of well-being and stimulate appetite
Adverse effects:
Fluid retention, hypertension, hyperglycaemia, increased appetite, dyspepsia, Cushing's syndrome
Muscarinic Receptor Antagonists
Drugs:
Hyoscine hydrobromide
Mechanism of action:
Blocks the action of ACh on M1 receptors in vomiting centre and vestibular nuclei
Non-selective muscarinic receptor antagonist leading to adverse effects
Adverse effects:
Dry mouth, dry eyes, blurred vision, constipation, urinary retention, tachycardia
Clinical use:
Prevention of motion sickness (optimal 30 minutes before)
H1 Receptor Antagonists
Drugs:
Promethazine, Dimenhydrinate, Doxylamine
Mechanism of action:
Blocks action of histamine on H1 receptors in the vomiting centre and vestibular nuclei
Also called "sedating antihistamines"
Adverse effects:
Sedation
Also blocks muscarinic receptors causing dry mouth, dry eyes, blurred vision, constipation, urinary retention etc.
Clinical use:
Prevention of motion sickness (optimal 30 minutes before)