Clinical Pharmacology

Question 1

What is Clinical Pharmacology

Answer 1

The study of clinical effects of drugs on patients

Question 2

What is Pharmacodynamics?

Answer 2

Action of dug
The effect a drug has on the body
What does it act on?
What is the response?

Question 3

What is pharmacokinetics?

Answer 3

The effect the body has on the drug
Where does the drug go?
Movement of drug within the body

Question 4

What are considerations when choosing a drug?

Answer 4

• Disease factors
  ○ Importance of specific diagnosis
  ○ Specific therapeutic goals
  ○ Sometimes have to treat symptoms in emergencies rather than diagnosis
  
  • Drug
    ○ Efficacy and safety
    ○ Licenced
    ○ Off-label
    ○ Formulation - time period
  • Owner
    ○ Finances
    ○ Physical ability to administer
  • Patient
    ○ Temperament
    ○ Age
    ○ Pregnant?
    ○ Co-morbidities
  • Practice
    ○ Corporate practices have specific drug brands
    ○ Shelf stock and turnover
  • Compliance
    ○ Training and education
    ○ Therapeutics options

Question 5

What are the different drug targets?

Answer 5

Receptors
Ion channels
Structural proteins
Enzymes
Carrier molecules
DNA

Question 6

What is an agonist drug?

Answer 6

A drug that binds to a receptor and causes the same action as the ligand that normally binds to the receptor
As dose increases, effect also increasers linearly
Eventually reaches a threshold where receptor is maximally stimulated and can’t elicit further response

Question 7

What is a full agonist?

Answer 7

A drug whose efficacy is sufficient that it produces a maximal response when less than 100% of receptors are occupied
Maximal dose elicits maximal effect

Question 8

What is a partial agonist?

Answer 8

Has lower efficacy, such that 100% occupancy elicits only a sub-maximal response
Maximal dose doesn’t elicit maximal effect

Question 9

Efficacy definition

Answer 9

Maximum therapeutic response that a drug can produce
Related to whether they are full or partial agonists

Question 10

Potency definition

Answer 10

Amount of drug required to produce 50% of maximal effects (ED50)

Question 11

Specificity definition

Answer 11

○ Capacity of a drug to cause a particular action in a population
○ Only has one action
Example: a drug of absolute specificity of action might decrease or increase, a specific function of a given protein or cell

Question 12

Selectivity definition

Answer 12

○ Relates to a drugs ability to target only a selective population
I.e. cell/tissue/ signalling pathway, protein etc in preference to others.
○ Example: Atenolol is a b1-selective adrenoreceptor antagonist (binds to b1 only) while propranolol is a non-selective b-antagonist (also binds to other receptors)

Question 13

What is the Therapeutic index

Answer 13

(Toxic dose) / (therapeutic dose)

Question 14

What is an antagonist drug?

Answer 14

A drug that binds to a receptor and inhibits the same normal action

Question 15

Competitive antagonist

Answer 15

Binds to the same site as the agonist but does not activate it, thus blocks the agonist’s action
Shifts dose response curve to right

Question 16

Non-competitive antagonist

Answer 16

Binds to an allosteric site of the receptor, or irreversibly binds to the active site of the receptor.

Question 17

Tachyphylaxis definiton and causes

Answer 17

Loss of drug sensitivity
* The effect of a drug can decrease when given continuously or repeatedly due to:
○ Change in receptors (become resistant to drug stimulation/conformational changes)
○ Loss of receptor number
○ Exhaustion of mediators
○ Increased metabolic degradation of the drug
○ Physiological adaptation (crosstalk between body systems, one takes over)
Drug transporters (active extrusion of the drug)