pharmacology definitions

Question 1

define drug interactions

Answer 1

how one drug affects the action of another drug,

can be positive or negative,

3 main classes

Question 2

what are the 3 main classes of drug interactions

Answer 2

1. physiochemical
2. pharmacodynamics
3. pharmacokinetics

Question 3

describe the drug interaction: physiochemical

Answer 3

2 drugs reacting, completely independent of what’s happening in the body

eg. same effect in test tube as body

Question 4

give an example of a physiochemical reaction

Answer 4

Overdose of paracetamol →

given ‘activated charcoal’ in hospital →

it sticks to the paracetamol and prevents it from being absorbed

this is ADSORPTION

Question 5

what’s the difference between adsorption and absorption?

Answer 5

Adsorption compounds cling to the surface of the molecule,

whereas absorption substances enter the bulk phase of a liquid or solid.

Question 6

define bioavailability

Answer 6

how much a drug is available for use over a period of time.

is the fraction of an administered drug that reaches the systemic circulation unaltered

Question 7

when is bioavailability always 100%?

Answer 7

when a medication is administered intravenously, its bioavailability is 100%.

because it all reaches the systemic circulation

Question 8

define pharmacodynamic

Answer 8

Any effect the drug has on the human body (intended or not)

Question 9

define Pharmacokinetics

Answer 9

what the body does with the drug , the action of drugs in the body

(the disposition of a compound within an organism)

aka. the study of drug metabolism

Question 10

what is an enzyme inhibitor?

Answer 10

An enzyme inhibitor is a molecule that binds to an enzyme and decreases its activity.

It prevents the substrate from entering the enzyme’s active site and prevents it from catalysing its reaction

Question 11

define transport

Answer 11

when molecules move across a cell membrane

Question 12

define active transport

Answer 12

moves ions from a lower concentration to a higher concentration. Needs energy from ATP

Question 13

define xenobiotics

Answer 13

compounds foreign to an organism normal biochemistry

such as any drug or poison

Question 14

define a drug

Answer 14

a medicine or other substance which has a physiological effect when ingested or otherwise introduced into the body

Question 15

define pharmacology

Answer 15

the branch of medicine concerned with the uses, effects and modes of action of drugs

Question 16

what is meant by Drugability?

Answer 16

the ability of a protein target to bind small molecules with high affinity (sometimes called ligandability).

A protein is ‘druggable’

Question 17

what is a receptor?

Answer 17

a component of a cell that interacts with a specific ligand and initiates a change of biochemical events leading to the ligands observed effects.

Question 18

what is a ligand?

Answer 18

a molecule that binds to another (usually larger) molecule

can be exogenous or endogenous

Question 19

what is an agonist?

Answer 19

a compound that binds to a receptor and activates it

can be full or partial

Question 20

what is an antagonist?

Answer 20

a compound that reduces the effect of an agonist

(DOES NOT ACTIVATE A RECEPTOR)

Question 21

what does EC50 on a log dose response curve mean?

Answer 21

‘half maximal effective concentration’

ie. the concentration of a drug needed to cause half of the maximum possible effect/response

Question 22

define potency

Answer 22

a measure of drug activity expressed in terms of the amount required to produce an effect of given intensity.

A highly potent drug evokes a given response at low concentrations

whether a drug is ‘strong’ or ‘weak’ relates to how well the drug binds to the receptor, the binding affinity.

Question 23

define affinity

Answer 23

describes how well a ligand binds to the receptor

(agonists and antagonists both have affinity)

Question 24

define efficacy

Answer 24

describes how well a ligand activates the receptor

( agonists have efficacy, antagonists have 0 efficacy)

this is the concept of full or partial agnostic

Question 25

what is a receptor reserve?

Answer 25

Some agonists only need to activate a small fraction of the existing receptors to produce maximal response. Have SPARE Partial agonists don't have a receptor reserve

Question 26

what is signal transduction?

Answer 26

a basic process involving the conversion of a signal from outside the cell to a functional change within the cell. (After a ligand interaction with receptor on cell surface)

Question 27

what is signal amplification

Answer 27

action to increase the strength of a signal

Question 28

define tolerance

Answer 28

biological response to a drug diminishes SLOWLY down regulation of the receptors with prolonged use, Need higher doses to achieve the same effect

Question 29

define desensitisation

Answer 29

biological response to a drug diminishes RAPIDLY

Question 30

what is parenteral administration?

Answer 30

administration that bypasses digestive system ie. not orally given

Question 31

define partial agonists

Answer 31

drugs that bind to and activate a given receptor, but have only partial efficacy at the receptor relative to a full agonist not picked up by all receptors to

Question 32

define and ADR?

Answer 32

Adverse drug reactions: unwanted or harmful reactions following the administration of drugs or combination of drugs under normal conditions of use and are suspected to be related to the drug. Has to be noxious and unintended .

Question 33

define side effects

Answer 33

an unintended effect of a drug related to its pharmacological properties can include unexpected benefits of treatment

Question 34

define hypersensitivity

Answer 34

= objectively reproducible symptoms or signs, initiated by exposure to a defined stimulus at a dose tolerated by normal subjects’ and may be caused by immunologic (allergic) and non‐immunologic mechanisms’

Question 35

define Anaphylaxis

Answer 35

an acute allergic reaction to an antigen to which the body has become hypersensitive

Question 36

define Cholinergic

Answer 36

Cholinergic medications act upon the neurotransmitter acetylcholine (ACh) and its receptors

Question 37

define Adrenergic

Answer 37

Adrenergic medications bind to adrenergic receptors throughout the body. (these are adrenaline and noradrenaline receptors)

Question 38

define afferent nerves

Answer 38

signal towards the brain/spinal cord

Question 39

define efferent nerves

Answer 39

signal away from the brain/spinal cord

Question 40

define stereoisomers

Answer 40

have the same molecule formula and sequence of bonded atoms, but differ in the 3D orientations of their atoms in space

Question 41

define absorption

Answer 41

the process of transfer from the site of administration into the general or systemic circulation

Question 42

define elimination

Answer 42

The removal of a drugs activity from the body

Question 43

define half life

Answer 43

this is the time taken for a concentration to reduce by one half

Question 44

define drug distribution

Answer 44

Rate and extent of movement of a drug into tissues from blood

Question 45

define an inverse agonist

Answer 45

a drug that binds to the same receptor binding site as an agonist, but induces an opposite response to that agonist

Question 46

define a competitive antagonist

Answer 46

directly competes with the agonist by binding to the same active site and blocking it it inhibits (does not activate) is reversible and surmountable

Question 47

define a non competitive antagonist

Answer 47

A non-competitive antagonist binds to an allosteric binding site on the receptor, to block its activation It does not completely block the effect of the agonist and it isn't competing with the antagonist for the same binding site

Question 48

define selectivity

Answer 48

refers to a drug's ability to preferentially produce a particular effect its the degree to which a drug acts on a given site relative to other sites. Relatively nonselective drugs affect many different tissues or organs. better term to use (over specificity)

Question 49

define specificity

Answer 49

the capacity of a drug to cause a particular action in a population. compounds are nerve 100% specific the measure of a receptors ability to respond to a single ligand

Question 50

example of an agonist

Answer 50

Adrenaline is an agonist at beta adrenoceptors Opioids are agonists for opioid receptors in the brain

Question 51

define: first pass metabolism

Answer 51

rapid uptake and metabolism of an agent into inactive compounds by the liver, immediately after enteric absorption and before it reaches the systemic circulation i.e. concentration of the drug is greatly reduced before it reaches systemic circulation.