L3.10 Agonism

Question 1

What are the features of paracetamol?

Answer 1

• regarded as safe but has the ability to be fatal
• therapeutic window seems unlimited, but restricted by liver damaging side effects
• brain metabolite that activates cannabinoid receptors

Question 2

What are the similarities and differences between isoprenaline and prenalterol?

Answer 2

Both beta selective, but prenalterol prefers B1. Isoprenaline is a full agonist and is more potent.

Question 3

What is EC50?

Answer 3

Estimated concentration for 50% of maximal drug response

Question 4

What are the partial agonists and their key features?

Answer 4

• Salbutamol: asthma relieve rpartialness is important to prevent down-regulation of B2 adrenoreceptor
• Buprenorphine: Partial agonism to prevent desensitisation and dependence (pain reliever)
• Sumatriptan: Anti-migraine - vasoconstriction of brain surface blood vessels & coronary arteries (partiality means that it is safe enough to use, if it were a full agonist it would cause heart attacks)
• Pindolol: Antagonist - weak partial agonist of beta receptor. Preserve exercise tolerance and reduce tendency for cold extremities due to vasodilation