Pharmacology

Question 1

Pharmacodynamics is…

Answer 1

What a drug does to the body

Question 2

Pharmacokinetics is….

Answer 2

What the body does to a drug

Question 3

Affinity is…

Answer 3

Strength of association between ligand and receptor

Question 4

Efficacy is….

Answer 4

Ability of an agonist to evoke a cellular response

Question 5

Antagonist is…

Answer 5

Drug that blocks the actions of an agonist

Question 6

Agonist is…

Answer 6

Drug that binds to a receptor to produce a cellular response

Question 7

Agonist possess ___________ while antagonist possess ________________ but lack _________

Answer 7

Affinity and efficacy
Affinity but lack efficacy

Question 8

Competitive antagonism

Answer 8

Binding of agonist and antagonist occur at same (orthosteric) site

Question 9

Competitive antagonism curve changes

Answer 9

Parallel rightward shift of agonist concentration response curve with no depression in maximal response

Question 10

Non-competitive antagonism

Answer 10

Agonist binds to normal site and antagonist binds to separate (allosteric) site

Both may occupy sites simultaneously, but activation cannot occur when antagonist is bound

Question 11

Non-competitive antagonism curve changes

Answer 11

Depress the slop and maximum response curve, but do not cause a rightward shift

Question 12

Absorption is

Answer 12

Process by which a drug enters the body from its site of administration

Question 13

Distribution is……

Answer 13

Process by which drug leaves circulation and enters the tissues perfused by blood

Question 14

Metabolism is…..

Answer 14

Process by which tissue enzymes catalyse chemical conversion of a drug to a more polar form that is more readily excreted from the body

Question 15

Excretion is…

Answer 15

Processes that remove the drug from the body

Question 16

Factors Controlling Drug Absorption

Answer 16

Solubility
Chemical stability
Lipid to water partition coefficient
Degree of ionisation

Question 17

T or F: Only ionised forms readily diffuse across the lipid bilayer

Answer 17

False → only unionised forms readily diffuse across the lipid bilayer

Question 18

Volume of distribution (Vd) is….

Answer 18

Volume into which a drug appears to be distributed with a concentration equal to that of plasma

Question 19

How is Vd calculated for IV preparation of drug

Answer 19

Vd = dose/plasma concentration

Question 20

T or F: The higher the therapeutic ratio the safer the drug

Answer 20

True

Question 21

How is Therapeutic Ratio calculated

Answer 21

Therapeutic Ratio = MTC/MEC

Question 22

Therapeutic Ratio is…..

Answer 22

Any concentration of drug between the minimum effective concentration (MEC) and maximum tolerated concentration (MTC)

Question 23

First order kinetics

Answer 23

Rate of elimination directly proportional to drug concentration → most drugs have this

Question 24

Clearance is….

Answer 24

The volume of plasma cleared of drug in unit time

Question 25

In first order kinetics, half-life is inversely proportional to _______________

Answer 25

Elimination rate constant

Question 26

How is Rate of elimination calculated

Answer 26

Rate of elimination = Clearance x Plasma concentration

Question 27

Half-life is

Answer 27

Time for the concentration of drug in plasma to halve

Question 28

Loading dose is...

Answer 28

Initial higher dose of drug before stepping down to lower maintenance dose It accelerates the time at which a steady state can be reached and when plasma concentration becomes adequate

Question 29

Depolarisation

Answer 29

The membrane potential becomes less negative (or even positive)

Question 30

Hyperpolarisation

Answer 30

The membrane potential becomes more negative

Question 31

Sympathetic preganglionic neurones always _____ while post ganglionic neurone usually _______

Answer 31

ACh Noradrenaline

Question 32

Sympathetic system has ____________ outflow

Answer 32

Thoraco-Lumbar (T1-L2)

Question 33

Effects of sympathetic system on the body

Answer 33

Increases HR and force of contraction Relaxes bronchi, decreases mucus production Reduces GI motility and constricts sphincters Vasoconstriction but relaxation in skeletal muscle Release of adrenaline from adrenal gland Ejaculation

Question 34

Parasympathetic preganglionic neurones always _____ while post ganglionic neurone usually _____

Answer 34

ACh

Question 35

Parasympathetic system outflow from...

Answer 35

Cranial nerves III, VII, IX and X Cranio-sacral outflow Thoraco-lumbar outflow Sacral spinal nerves

Question 36

Effects of parasympathetic system on the body

Answer 36

Decreases HR Bronchoconstriction, stimulates mucus production Increases GI motility and relaxes sphincters No effect on blood vessels or adrenal glands Erection

Question 37

Selective, competitive antagonist of a1 Vasodilator used as anti-hypertensive Which drug?

Answer 37

Prazosin

Question 38

Selective, competitive antagonist of B1 Used as an anti-anginal and anti-hypertensive agent Which drug?

Answer 38

Atenolol

Question 39

Selective agonist at B2 Used as bronchodilator in asthma Which drug?

Answer 39

Salbutamol

Question 40

Competitive antagonist of Muscarinic ACh receptors, does not block nicotinic ACh receptors Blocks parasympathetic division of ANS Used to reverse bradycardia post MI and in AChE poisoning Which drug?

Answer 40

Atropine

Question 41

What are the different G-protein coupled adrenoceptor subtypes and their functions at sympathetic neuroeffector junctions?

Answer 41

B1 – stimulates through Gs stimulating adenylyl cyclase increasing heart rate and force B2 – stimulates through Gs stimulating adenylyl cyclase causing relaxation bronchial and vascular a1 – stimulates through Gq stimulating phospholipase C causing contraction of vascular smooth muscle a2 – stimulates through Gi stimulating inhibition of adenylyl cyclase causing inhibition of NA

Question 42

What are the individual roles of muscarinic receptors M1, M2 and M3?

Answer 42

M1 – signals to specific G-protein (Gq) which stimulates phospholipase C which causes increased acid secretion in the stomach. M2 – signal to specific G-protein (Gi) which stimulates inhibition of adenylyl cyclase which opens K+ channel causing decreased heart rate. M3 – signals to specific G-protein (Gq) which stimulates phospholipase C production which causes increased secretion of saliva or contraction of visceral smooth muscle.

Question 42

Which two receptors can ACh activate?

Answer 42

Nicotinic (ligand gated receptors) Muscarinic (G-protein coupled receptors)

Question 43

Describe how G-proteins function

Answer 43

Signal Agonist binds to and activates receptor G protein couples with receptor Guanine nucleotide exchange (GDP dissociates and GTP binds to alpha subunit) Subunit dissociation (G protein dissociates into alpha subunit and beta-gamma subunit) G protein alpha subunit combines with and modifies activity of effector to bring about the desired signal Agonist may dissociate from receptor at any time, but signaling will still occur

Question 44

Which is faster, ligand gated ion channels or G-protein coupled?

Answer 44

Ligand gated channels

Question 45

Zero order kinetics

Answer 45

Drugs that are eliminated at a constant rate, regardless of their concentration An increase in drug concentration will have no effect on the rate of elimination

Question 46

How many half lives does it take to reach a steady state?

Answer 46

5

Question 47

How is steady state calculated

Answer 47

Maintenance dose rate/clearance

Question 48

Phase 1 metabolism of drugs causes change in drug via.....

Answer 48

Oxidation, reduction or hydrolysis

Question 49

Phase 2 metabolism of drugs causes change in drug via.....

Answer 49

Conjugation of drug with a polar molecule to form a water-soluble metabolite

Question 49

Conjugated product is readily excreted via the __________ in phase 2 metabolism

Answer 49

Kidneys