Mechanisms of Action

Drugs can act in four ways:

• Receptors
  • GPCR
  • Intracellular
    • Cytoplasmic
    • Intranuclear
      e.g. Steroids, which alter RNA expression.

• Ion Channels
  • Blockade
  • Allosteric modulation

• Enzyme interaction
  An enzyme is a biological catalyst, increasing the speed of reaction. Enzyme interaction can be:
  • Irreversible inhibition
    • e.g. Aspirin, which irreversibly inhibits platelet thromboxane production.
  • Reversible inhibition
  • Competitive antagonism
    • e.g. ACE-I.
  • Non-competitive antagonism

• Physicochemical
  • Osmotic
    • e.g. mannitol.
  • Acid-base
    • e.g. antacids.
  • Chelation
  • Redox reactions

References

1. Peck TE, Hill SA. Pharmacology for Anaesthesia and Intensive Care. 4th Ed. Cambridge University Press. 2014.
2. Petkov V. Essential Pharmacology For The ANZCA Primary Examination. Vesselin Petkov. 2012.