Basic Principles of Pharmacology

Question 1

Define pharmacology

Answer 1

This is the study of substances that interact with living systems through chemical processes

Question 2

What are the the 5 R of medication safety

Answer 2

Right
1. Dose
2. Time
3. Route
4. Patient
5. Drug

Question 3

Define pharmacokinetics

Answer 3

This is the time course of the drug and its metabolites through the body

Question 4

What are the 4 main principles of pharmacokinetics

Answer 4

1. Absorption
2. Distribution
3. Metabolism
4. Excretion

Question 5

What is the clearance

Answer 5

This is a measure of the bodies ability to eliminate a drug

Question 6

What is the volume of distribution

Answer 6

This is a measure of a drugs propensity to remain in the plasma or distribute into the tissue thus a drug with a high volume of distribution will leave the plasma and enter the extravascular compartment

Question 7

What is the half life

Answer 7

This is the time taken for the body to reduce the conc. of a drug by half

Question 8

Define the therapeutic window

Answer 8

This is the difference between the minimal toxic conc. and the maimal effective conc.

Question 9

How long does it take to reach the steady state

Answer 9

5 half lives

Question 10

What is a loading dose

Answer 10

A larger than maintenance dose that helps to reach the therapeutic window faster

Question 11

Define absorption

Answer 11

This is how much of the administered drug reaches the systemic circulation

Question 12

What is first pass metabolism

Answer 12

This is the portion of orally administered drug that is removed by the liver before it reaches the systemic circulation

Question 13

What are P glycoprotein transporters

Answer 13

These are active transporters that efflux lipid soluable drugs that cross the cell membrane in the gut and blood tissue barriers

Question 14

Which drugs are able to pass through the BBB

Answer 14

1. Small lipid soluable drugs
2. Drugs that are substrates of transporters

Question 15

What is a prodrug

Answer 15

This is a drug that is inactive or less active as compared to its metabolite and so needs to be metabolised to exert its effect

Question 16

What are the 2 main processes of drug metabolism

Answer 16

1. Introduction or exposure of the functional group through a ROH rxn
2. Polar conjugation: This is where a polar group is added to facilitate excretion

Question 17

What is meant by first order kinetics of metabolism

Answer 17

This is where a constant proportion of the drug is removed per unit time e.g. 10% and so the rate of metabolism increases with increased conc.

Question 18

What is zero order kinetics in drug metabolism

Answer 18

This is where a constant amount of drug is removed per unit time and so there is exponential increases in drug conc. as a fixed amount is removed

Question 19

What is meant by inhibition and induction

Answer 19

Inhibition: This is where a drug binds to an enzyme causing it to stop functioning thus increasing the conc. of drug in circulation as it is not removed

Question 20

What is meant by induction

Answer 20

This is where there is increased expression of the genes that regulate enzymes and so there is an increase in the conc. of the enzyme causing faster removal of a drug

Question 21

Who are the special populations in prescribing drugs

Answer 21

Liver and renal disease
Elderly and children
Pregnant and lactating
Porphyria

Question 22

Define pharmacodynamics

Answer 22

This the study of the biochemical and physiological effects of the drugs

Question 23

What is the ED50

Answer 23

This is the dose that elicits an effective response in 50% of individual

Question 24

What is the LD50

Answer 24

This is the lethal dose in 50% of individuals

Question 25

What is meant by potency

Answer 25

The amount of drug that is necessary to achieve a certain effect

Question 26

What is the efficacy

Answer 26

This is the maximum possible effect of the drug

Question 27

What is an agonist

Answer 27

This is a drug that binds to and activates that receptor

Question 28

What is an antagonist

Answer 28

This a molecule that binds to a receptor and in doing so prevents other molecules from binding

Question 29

What is the difference between a full and a partial agonist

Answer 29

A full agonist is a agonist that once it occupies the reseptor it initiated the full physiological effect and a partial produces a submaximal response

Question 30

What are the 4 main types of antagonists

Answer 30

1. Pharmacological antagonist: This is when the antagonist interferes directly with the receptor
2. Physiological: 2 drugs act in opposing physiological effects
3. Chemical: This is were 2 drugs in solution react with one another to neutralize one another
4. Physical: They act through physical properties, such as solubility, adsorption, or distribution, rather than molecular interactions with receptors or enzymes e.g. charcoal

Question 31

What is meant by tolerance

Answer 31

This is where larger doses are needed to experience the same effects

Question 32

What are the 3 main mechanisms of tolerance

Answer 32

1. Pharmacokinetic clearance: This is where there is increased clearance induced by repeated doses
2. Pharmacodynamic clearance: This is where there is a change to the number of receptors or their function due to repeated exposure to the drug
3. Behavioral tolerance: This is learned behavior that leads to diminished effects of the drugs