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Paper I — 2021 May (Supplementary) (2010 Scheme) — Q4

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Paper I
2021 May (Supplementary) (2010 Scheme) · 40 marks · 120 min

Question

Drug antagonism

Q43 marksShort Notes

Answer

Drug antagonism is the phenomenon where one drug (antagonist) diminishes or abolishes the action of another (agonist).

Types

  • Physical antagonism: Based on physical properties (e.g., activated charcoal adsorbing a poison)
  • Chemical antagonism: Antagonist chemically combines with agonist forming an inactive compound (e.g., protamine sulphate neutralizing heparin)
  • Physiological (functional) antagonism: Two agonists act on different receptors producing opposite effects on the same physiological function (e.g., histamine vs. adrenaline on bronchial smooth muscle)
  • Receptor (pharmacological) antagonism:
    • Competitive (reversible): Antagonist competes for the same receptor site; surmountable by increasing agonist concentration (e.g., atropine vs. acetylcholine)
    • Non-competitive (irreversible): Antagonist binds irreversibly/allosterically; not surmountable (e.g., phenoxybenzamine at α receptors)
  1. 1Pharmacodynamics

Other Years Asked

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  4. 4Drug Antagonism2023 July (Supplementary) (2010 Scheme)Short Note · 3 marks
  5. 5Drug antagonism2017 February (2010 Scheme)Short Note · 3 marks
  6. 6G-protein coupled receptors2020 February (Supplementary) (2010 Scheme)Short Note · 3 marks
  7. 7Assertion (A): Allopurinol can precipitate acute gout. Reason (R): Inhibition of uric acid synthesis mobilizes tissue store of uric acid in to plasma.2025 March (Supplementary (SAY)) (2019 Scheme)MCQ (A/R) · 1 mark
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  9. 9Drug induced parkinsonism2013 April (2010 Scheme)Short Answer · 1 mark
  10. 10Dimercaprol2022 May (Supplementary) (2010 Scheme)Short Answer · 1 mark
  11. 11Assertion (A): Beta-2 agonists, such as salbutamol, are used to treat asthma. Reason (R): Beta-2 agonists work by stimulating beta-2 adrenergic receptors on bronchial smooth muscles, causing bronchodilation.2025 March (Supplementary (SAY)) (2019 Scheme)MCQ (A/R) · 1 mark
  12. 12Substances that precipitate superficial surface proteins without penetrating the cells and toughen the skin making it mechanically stronger and decrease exudation are called:2024 December (Supplementary) (2019 Scheme)MCQ · 1 mark
  13. 13Disease modifying anti-rheumatic drugs2018 February (2010 Scheme)Short Answer · 1 mark
  14. 14Potassium channel openers2021 May (Supplementary) (2010 Scheme)Short Answer · 0.3 marks
  15. 15Potassium channel openers2021 December (Supplementary) (2010 Scheme)Short Answer · 0.3 marks
  16. 16Epidermal growth factor receptor inhibitors2022 February (2019 Scheme)Short Answer · 0.2 marks

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