Cardiff Q - Pharmacology

Question 1

Pharmacokinetics

Answer 1

What body does to drug

Absorption, distribution, metabolism, etc

Question 2

Pharmacodynamics

Answer 2

What the drug does to the body

Question 3

Methods of drug action / targets

Answer 3

Receptors
Ion channels
Enzymes
Hormones
Neurotransmitters
Transport systems
Physicochemical

Question 4

Receptor definition

Answer 4

Proteins integral to a cell membrane

Question 5

Ligand definition

Answer 5

A substance able to bind to a receptor

Question 6

Full agonist

Answer 6

Binds to receptor and produces maximum response

Question 7

Partial agonist

Answer 7

Binds to receptors but produces submaximal response

Question 8

Inverse agonist

Answer 8

Binds to receptor but produces opposite effect to endogenous agonist

has affinity but efficacy = -1

Question 9

Allosteric modulator

Answer 9

Binds to receptor at a separate site to that of the endogenous agonist

Changes conformational shape

Can affect affinity and efficacy

Question 10

Factors which affect ability of molecule to pass through cell membrane

Answer 10

Molecular size
Concentration gradient
Ionisation and pKa
Lipid solubility
Protein binding

Question 11

pKa

Answer 11

Lipophilic cell membrane only allows uncharged portion of a drug through

pKa = the pH at which 50% of the drug is ionised and 50% of the drug is unionised (-log10 [Ka])

Ka = acid dissociation constant

The lower the pKa, the stronger the acid

For an acid drug: if pH > pKa = more ionised, therefore less effective / slower onset time

For a base drug: if pH < pKa = more ionised, therefore less effective / slower onset time

Here the pH relates to the environment to which the drug is administered - eg may be blood pH, or may be abscess pH (eg why local anaesthetics don’t work in pus areas)

Question 12

Acid definition

Answer 12

Proton donor
H+

Question 13

Base definition

Answer 13

Proton acceptor
OH-

Question 14

Acid examples of drugs

Answer 14

Aspirin
Thiopentone
Paracetamol
Propofol
Atropine
Furosemide

Question 15

Some effects of protein binding ton drugs

Answer 15

Only unbound portion of drug in plasma is free to cross the cell membrane

Albumin binds acids

Question 15

Bases example of drugs

Answer 15

Opioids
Local anaesthetics
Ketamine
Midazolam
Etomidate
Diazepam

Question 16

Isomer definition

Answer 16

Molecules with the same molecular formula but different anatomical arrangement

Can be structural isomer or stereo isomer

Question 17

Structural isomer

Answer 17

Different arrangement of elements / chains

Question 18

Stereo isomer types

Answer 18

Geometrical isomer (aka cis-trans isomer) - different orientation around a double bond

Optical isomer (aka enantiomer) - mirror images

Question 19

Volume distrubution

Answer 19

Theoretical volume which the drug must disperse in order to produce a measured plasma concentration

Affected by lipid solubility, tissue protein binding….

Question 20

Bioavailability

Answer 20

Fraction of drug administered that reaches the systemic circulation

Question 21

Context sensitive half time graph of various anaesthetic drugs - need to learn this for viva

Answer 21