Question
List three classes of Antiemetics. Write the mechanism of action, uses and adverse
effects of the most effective Antiemetic group. (3+5)
Q7 8 marks Short Essays ★ ✓
Answer
Three classes of antiemetics
5-HT3 receptor antagonists — Ondansetron, Granisetron
D2 receptor antagonists — Metoclopramide, Domperidone
NK1 receptor antagonists — Aprepitant
Most effective group — 5-HT3 receptor antagonists
Mechanism : block serotonin (5-HT3) receptors both peripherally (on vagal afferents — chemotherapy damages intestinal mucosa, triggering enterochromaffin cells to release serotonin) and centrally at the chemoreceptor trigger zone, interrupting the dominant emetogenic pathway activated by chemotherapy/radiotherapy.
Uses : chemotherapy-induced nausea and vomiting (first-line, most effective class for this indication), radiotherapy-induced emesis, postoperative nausea/vomiting.
Adverse effects : headache and constipation (5-HT3 receptors also mediate normal GI motility), QT prolongation (a class-wide caution, more prominent with ondansetron — requiring care with other QT-prolonging drugs and in patients with cardiac risk factors).
1 Antiemetics
Other Years Asked
1 Enumerate Antiemetic drugs. Explain the Mechanism of action, uses and adverse effect of
any one group.
Briefly describe proton pump inhibitors (6+4+5) 2024 June (Supplementary) (2019 Scheme) Essay · 15 marks 2 Enumerate Antiemetics. Add a brief note on mechanism of action, uses and adverse effects of the most
effective group. (3+3) 2025 March (Supplementary (SAY)) (2019 Scheme) Short Essay · 6 marks 3 Metoclopramide 2022 May (Supplementary) (2010 Scheme) Short Note · 3 marks 4 Ondansetron 2019 February (2010 Scheme) Short Note · 3 marks 5 Aprepitant 2018 February (2010 Scheme) Short Note · 3 marks 6 Ondansetron 2024 August (Supplementary) (2010 Scheme) Short Note · 3 marks 7 Metoclopramide 2021 February (Supplementary) (2010 Scheme) Short Note · 3 marks 8 Domperidone 2019 July (Supplementary) (2010 Scheme) Short Note · 3 marks 9 Aprepitant 2016 February (2010 Scheme) Short Answer · 1 mark 10 Metoclopramide in vomiting. 2025 March (Supplementary) (2010 Scheme) Short Answer · 1 mark 11 Cinnarizine 2023 July (Supplementary) (2010 Scheme) Short Answer · 1 mark 12 Metoclopramide 2023 March (Supplementary) (2010 Scheme) Short Answer · 1 mark 13 5HT3 Antagonist (eg. ondansetron) is used in Chemotherapy induced vomiting 2023 March (Supplementary) (2010 Scheme) Short Answer · 1 mark 14 5HT antagonists 2013 April (2010 Scheme) Short Answer · 1 mark 15 Antiemetic agents 2015 February (2010 Scheme) Short Answer · 1 mark 16 Mechanism of action of metoclopramide 2014 September (Supplementary) (2010 Scheme) Short Answer · 1 mark 17 Vomiting 2013 September (Supplementary) (2010 Scheme) Short Answer · 1 mark 18 Metoclopramide. 2024 March (Supplementary) (2010 Scheme) Short Answer · 1 mark 19 Motion sickness. 2016 October (Supplementary) (2010 Scheme) Short Answer · 1 mark 20 Domperidone in chemotherapy induced vomiting. 2022 October (Supplementary) (2010 Scheme) Short Answer · 0.3 marks 21 Antiemetics 2021 February (Supplementary) (2010 Scheme) Short Answer · 0.3 marks 22 Cetirizine for motion sickness
Name the following (Two examples for each): (8x1=8) 2022 February (2019 Scheme) Short Answer · 0.2 marks 23 Prokinetic agents. 2023 July (Supplementary) (2019 Scheme) Short Answer · 0.2 marks 
