Pharmacology 3

Question 1

What is Pharmacodynamics?

Answer 1

Study of how drugs affect the body

Question 2

What are the 4 major Drug targets?

Answer 2

Ion Channels
Receptors
Transporter proteins
Enzymes

Question 3

What are 4 Major drug properties?

Answer 3

Selectivity
Specificity
Potency
Efficacy

Question 4

What is Selectivity?

Answer 4

Describe ability of a drug to bind to a particular receptor - some bind to more than 1 so low selectivity e.g a B-Blocker propranolol

Question 5

What is Drug Specificity?

Answer 5

Refers to how drugs interact with a receptor when bound - specific ligands called ligand specificity but can bind with different configurations

Question 6

What is Drug Potency?

Answer 6

Dosage of drug needed to induce an effect dependent on receptor affinity

Question 7

What will a drug with Low affinity do?

Answer 7

Weakly bind to a receptor and readily disassociate from it, large doses to induce effect

Question 8

What will a drug with High affinity do?

Answer 8

Bind strongly to a receptor and stay bound giving rise to large physiological response

Question 9

What is Drug Efficacy?

Answer 9

Ability of drug to induce an effect - full agonists and partial agonists effect (therapeutic effect)

Question 10

How is Potency and Efficacy studied?

Answer 10

Dose response curves with organ bath experiments

Question 11

How does Dose Response Curve work?

Answer 11

Measure tissue response (force of contractions) to treatment with increasing drug concentration until Emax reached, converted and then plotted - sigmoidal curve

Question 12

How to Determine Potency and Efficacy from a Dose response curve?

Answer 12

2 values important, maximal response of the drug and EC50 (drug conc 50%)

Question 13

What is a Quantal response?

Answer 13

All or Nothing response - taking sample of population and determine dose at which drug is effective - histogram for median

Question 14

How can Toxic effects be in terms?

Answer 14

Median Lethal dose LD50 or Medial toxic dose TD50

Question 15

What is Therapeutic dose?

Answer 15

Produces a therapeutic effect in half or treated median effected dose ED50 , can calculate therapeutic index

Question 16

What are 5 Main Mechanisms for Drug Antagonism?

Answer 16

Chemical
Receptor
Non-competitive
Pharmacokinetic
Physiological

Question 17

What is Receptor Antagonism?

Answer 17

Describes blockade of receptor by a drug molecule, no efficacy but have an affinity compete for receptor site

Question 18

What does High/Low affinity lead to?

Answer 18

Low - reversible competitive

High - irreversible competitive

Question 19

What does Non-competitive Antagonist do?

Answer 19

Drug binds to an Allosteric site on receptor and prevent activation - converts to partial and activate signalling pathways

Question 20

What is Pharmacokinetic Antagonism?

Answer 20

Acts to increase clearance, reduce plasma concentrations that effect half life of drug

Question 21

What is Physiological Antagonism?

Answer 21

Interaction between 2 drugs that initiate opposing effects via different receptors

Question 22

What is tolerance?

Answer 22

Maintenance of drug response requiring increasing doses

Question 23

What is tolerance caused by?

Answer 23

Pharmacokinetic - metabolism of drug

Pharmacodynamic - Down regulation of receptors

Question 24

What is cross tolerance?

Answer 24

Repeated use of a drug effects the therapeutic function of another drug

Question 25

What is Receptor Desensitisation?

Answer 25

Lack of receptor response after prolonged stimulation - short term = post trans
long term = changes in gene regulation

Question 26

What is Tachyphylaxis?

Answer 26

Desensitisation with depletion a signalling molecule in synaptic vesicles