Pharmacodynamics

Question 1

What is pharmacodynamics?

Answer 1

• studies of the biological and therapeutic effects of drug, i.e how the drug acts on the body

Question 2

How do drugs act on our body?

Answer 2

• act on DNA
• via a chemical reaction
• by binding to protein molecules (also called primary drug targets / molecular targets)

Question 3

What are the primary drug targets?

Answer 3

• four regulatory proteins (spells rice):
  1. carrier molecules
  2. enzymes
  3. ion channels
  4. receptors

Question 4

What are carrier molecules?

Answer 4

• proteins that transport ions or small inorganic molecules across the cell membrane
• e.g. glucose, amino acids or neurotransmitters

Question 5

How do drugs act on carrier molecules

Answer 5

• drugs block the carrier molecule transport system

- e.g. SSRIs

Question 6

What are enzymes

Answer 6

• biological catalysts that carry out countless reactions
• reversible
• specific / lock and key
• active site

Question 7

How do drugs act on enzymes using competitive inhibition?

Answer 7

• when a drug and a substrate compete for an ‘active site’ on an enzyme
• normal reaction slowed down or inhibited
• e.g. NSAIDs

Question 8

How do drugs act on enzymes using non-competitive inhibition?

Answer 8

• drug destroys enzyme or distorts its shape
• permanent
• e.g. nerve gas; ‘Novichok

Question 9

What are ion channels?

Answer 9

• integral proteins embedded in the cell’s lipid bilayer membrane
• allows ions (Na+, K+) to move between extracellular and intracellular fluid

Question 10

How do drugs act on ion channels?

Answer 10

• directly linked to a receptor
• may help to open or close an ion channel
• physical blocking

Question 11

What are receptors?

Answer 11

• large group of proteins that are drug targets

- ligans: molecule/s that bind to receptors, the part of the molecule that FITS IN, key that is IN the lock

Question 12

How do drugs act on receptors?

Answer 12

• drugs bind to receptors on cell membranes or to receptors present in the cell’s cytosol
• lock and key analogy; specific
• bind to receptors as either an agonist or antagonist

Question 13

What is an agonist and what does it do?

Answer 13

• bind to and activate receptors and produces the same response as the endogenous ligand (our own chemicals)
• agonist potency depends on affinity and efficacy
• full agonist - producing maximum effects

Question 14

What is an antagonist and what does it do?

Answer 14

• bind to receptors and blocks access of endogenous ligand
• blockers
• efficacy = zero