Pharmacology

Question 1

Half-life

Answer 1

Time taken for the concentration of a drug to decrease by half

Question 2

Volume of distribution

Answer 2

The apparent volume a drug disperses into at steady state to produce the observed concentration

Question 3

Clearance

Answer 3

Amount of plasma cleared of drug per unit time. The units are the same as flow, in L/min

Question 4

Hepatic clearance

Answer 4

Volume of blood cleared of drug, by the liver, per unit time.

Question 5

First-order kinetics

Answer 5

Rate of reaction is dependent on the concentration of reactant, mostly used in the concept of elimination, when a constant % of drug is eliminated per unit time

Question 6

Zero-order process

Answer 6

Rate of reaction is independent of the concentration of reactant. Constant amount of drug eliminated per unit time

Question 7

Bioavailability

Answer 7

The % of drug reaching the systemic circulation, expressed as a fraction of the same amount of drug given IV

Question 8

What is hepatic extraction ratio

Answer 8

Fraction of substance removed from blood flowing through the liver during a single pass.

Question 9

Context-sensitive half time

Answer 9

Time taken for the plasma concentration to fall by 50% after the cessation of drug infusion, with the context being the duration of infusion

Question 10

Ke0

Answer 10

Rate constant of drug elimination from the effect site.
Main determinant of the time to peak effect from a bolus of drug.

Question 11

T1/2 Ke0

Answer 11

Value which describes the time taken to achieve 50% effect-site concentration when the plasma levels are maintained at steady state

Question 12

Purpose of TCI?

Answer 12

Achieve and maintain a predetermined target concentration of said drug, rapidly, and without overshooting

Question 13

Bristol method

Answer 13

Achieve plasma [propofol] of 3 microg/ml
Loading 1mg/kg
Immediate infusion at 10mg/kg/hr for 10 mins
then 8mg/kg/hr for 10 mins
then 6mg/kg/hr for 10mins

Plus N2O

Question 14

Typical remifentanil infusion targets?

Answer 14

plasma target
4ng/ml, or 0.2ug/kg/min infusion

Question 15

Drug

Answer 15

Any compound that affects a biochemical or physiological effect in the body

Question 16

mechanisms of drug effects

Answer 16

Physicochemical: mannitol, chelating agents
Receptor interaction
Enzyme activity alteration

Question 17

Ligand

Answer 17

Substance that binds to a specific site of a receptor

Question 18

Receptor

Answer 18

A protein containing a ligand binding site to bring about a response

Question 19

Dissociation constant

Answer 19

Concentration of a ligand required to cause 50% receptor occupancy

Question 20

Law of mass action

Answer 20

rate of chemical reaction is proportional to product of concentration of reactants

Question 21

Solution

Answer 21

A homogenous mixture to intimately combined to be distinguishable by looking

Question 22

Suspension

Answer 22

A heterogenous mixture where particles eventually settle out

Question 23

Emulsion

Answer 23

A stable suspension of small globules of 1 liquid in a second liquid

Question 24

Emulsifier

Answer 24

A surface-active agent that promotes the formation of an emulsion

Question 25

Loading dose

Answer 25

Initial higher dose of a drug given at the beginning to rapidly attain high plasma concentration

Question 26

Maintenance dose

Answer 26

Rate of drug administration equal to rate of elimination at steady state

Question 27

Therapeutic window

Answer 27

The range of drug dosages which can treat disease effectively without having toxic effects

Question 28

potency

Answer 28

amount of drug needed to produce a given effect A function of affinity and efficacy

Question 29

First order kinetics

Answer 29

fixed proportion of drug eliminated per unit time Constant half-life

Question 30

Zero order kinetics

Answer 30

Fixed amount of drug eliminated per unit time

Question 31

Hepatic extraction ratio

Answer 31

Fraction of drug removed from blood by the liver

Question 32

Eutectic mixture

Answer 32

mixture of 2 compounds in fixed proportions which behave with a single set of physical characteristics. EMLA has a lower melting point than the individual substances

Question 33

Affinity

Answer 33

How avidly a drug binds to the receptor

Question 34

Intrinsic activity

Answer 34

The magnitude of effect of a drug produced once bound to the receptor

Question 35

Agonist

Answer 35

drug that interact with a receptor to increase its activity

Question 36

Inverse agonist

Answer 36

Bind receptors and reduce the amount of receptors in the active conformation

Question 37

Antagonist

Answer 37

a substance with significant receptor affinity but no intrinsic activity

Question 38

Allosteric modulators

Answer 38

Bind at a site distant from the agonist receptor site and alter the binding characteristic of the agonist

Question 39

Poynting effect

Answer 39

Mixture of 2 gases has a different set of physicochemical properties than the individual components. i.e bubbling O2 through N2O lowers the critical temp to -7 degrees

Question 40

ED95

Answer 40

dose of NMB to produce 95% first twitch height reduction in 50% of the population

Question 41

Median effective concentration

Answer 41

the concentration of a drug that induces a specified response exactly halfway between baseline and maximum