pharmacodynamics

Question 1

nitroglycerin

Answer 1

• Eg nitroglycerin is taken
  § During an angina attack to relieve pain
  § Before activities that usually cause angina

Question 2

metoprolol

Answer 2

• Metoprolol must be taken regularly to reduce occurrence of angina episodes
  
  • Prophylactic administration
    
    • Typical for drugs used to treat chronic diseases

Question 3

Potency

Answer 3

• The dose required to produce and effect
  
  • A drug that produces its effects at lower doses is said to be more potent
    -

Question 4

Effectiveness

Answer 4

A drug that produces a greater maximum level of effect is said to be more effective

Question 5

• Affinity

Answer 5

• Tendency of a drug to bind to it’s target
  - Depends on the existence of
  § Complementary chemical forces of attraction and
  § Complementary 3D shapes between drug and target

Question 6

fraction of target bound by drug

Answer 6

[drug]/[drug].Ka

Question 7

Ka

Answer 7

concentration of the drug at which 50% of receptors are bound
□ A measure of affinity
□ Inverse relationship - low Ka means high affinity

Question 8

Rt

Answer 8

total number of receptors

Question 9

f

Answer 9

the efficiency of coupling between receptor activation and the end effect
○ Capacity of the activated receptor in creating an effect

Question 10

• Sigmoidal dose response curve

Answer 10

○ Plot of log[agonist] vs effect

Question 11

EC50

Answer 11

• Measures agonist potency

- Concentration of a drug required to produce 50% of its maximum response

Question 12

EC50 depends on

Answer 12

○ Affinity 
		○ Efficacy 
		○ Cell dependant parameters
			§ Density of receptors 
			§ Efficiency of coupling

Question 13

phenylephrine

Answer 13

nasal decongestant

Question 14

salbutamol

Answer 14

an asthma reliever

Question 15

Metoprolol binds

Answer 15

• Competitive antagonist
  
  • Binds to B1 adrenocepttor and occupies the binding site of the receptor it inhibitts the binding of adrenaline to the receptor
  • Blocks the binding and actions of adrenaline

Question 16

metoprolol causes

Answer 16

• Blocks the binding and actions of adrenaline
  ○ Decreases chances of oxygen debt
  ○ Decreases frequencies of angine attacks

Question 17

metoprolol side effects

Answer 17

- At higher concentrations 
		○ Metorpolol binds to B2 
			§ May cause adverse side effects 
			§ May worsen symptoms in people with asmtha 
			§ By reducing bronchodilatation

Question 18

• Labetolol

Answer 18

○ Has high affinity for alpha and beta adrenoceptors.

○ ADR selective antagonist

Question 19

• Propanolol

Answer 19

○ Beta adrenoceptor selective antagonist