Pharmodynamics and kinetics

Question 1

____ refers to how effective a drug is at producing a response

Answer 1

Efficacy

Question 2

drugs with a ____ first pass effect have ____ bioavailability

Answer 2

high, low

Question 3

what is the primary site of drug elimination

Answer 3

the kidney

Question 4

Rate of renal excretion = ?

Answer 4

filtration + secretion - reabsorption

Question 5

When does steady state occur?

Answer 5

occurs after multiple drug doses when the average drug concentration no longer changes, i.e. when the amount of drug going into the body is equivalent to the amount of drug leaving the body over the dosing interval. Approximate by multiplying half-life by 5.

Question 6

Which phase of drug metabolism is enzymatic, which increases water solubility via conjugation and deactivates active metabolites?

Answer 6

phase 2

Question 7

What is pharmacokinetics

Answer 7

what the body does to the drug

Question 8

Describe phase 2 of drug metabolism

Answer 8

enzymatic, increases water solubility via conjugation and deactivates active metabolites

Question 9

What is the primary site of drug metabolism

Answer 9

the liver

Question 10

which are more easily absorbed: hydrophilic or lipophilic drugs

Answer 10

lipophilic

Question 11

When environmental pH is lower than the drug pH, more of the ______ form predominates

Answer 11

un-ionized, protonated

Question 12

un-ionized drugs are more ____ soluble, and therefore cross cell membranes ____

Answer 12

lipid soluble, cross cell membranes readily

Question 13

What is bioavailability

Answer 13

the percentage of a drug dose that reaches systemic circulation

Question 14

The magnitude and percent of clinical response is called

Answer 14

clinical efficacy

Question 15

What is Tmax

Answer 15

the time at which the drug reaches Cmax, the highest measured concentraion in the plasma

Question 16

What is the consequence of a drug being protein bound?

Answer 16

it cannot be filtered through the glomerulus, and it is not typically bioavailable.

Question 17

What is the most important transport protein that moves drugs out of cells

Answer 17

P-glycoprotein

Question 18

What is ion-trapping

Answer 18

a phenomenon where the drug will accumulate more in the compartment where it is more ionized (aka the compartment that has a pH further from the drug’s pKa)

Question 19

Lipophilic drugs go into ____, hydrophilic drugs go into ____

Answer 19

fat, fluid compartmetns

Question 20

What is the Area under the time concentration curve (AUC) a measure of?

Answer 20

the animals total exposure to the drug

Question 21

If the environmental pH is higher than the drug pKA, the ____ form predominates

Answer 21

ionized (deprotonated) form

Question 22

Which of the four processes of pharmacokinetics is not applicable to IV administration?

Answer 22

Absorption, as it is immediately at Cmax in the blood

Question 23

What is Cmax and what does it determine?

Answer 23

the highest concentration achieved by the drug in the plasma. This is determined by bioavailability and relative rate of absorption, distribution, metabolism/elimination

Question 24

Rank the drug receptors from fastest to slowest

Answer 24

ligand gated
g-protein coupled
enzyme receptors
intracellular receptors

Question 25

What is the first phase of drug metabolism, and what happens

Answer 25

Redox reactions, carried out by cytochrome P450

Question 26

What are the phases of drug metabolism

Answer 26

redox Enzymatic

Question 27

What two things does metabolism increase in a drug

Answer 27

polarity and water solubility

Question 28

what type of administration can over-come the first pass effect

Answer 28

rectal

Question 29

equation for loading dose

Answer 29

loading dose= Vd x desired drug concentration

Question 30

what is pharmacological efficacy

Answer 30

the inhibition or activation of receptor activity

Question 31

what is potency

Answer 31

the concentraiton of a drug required to produce a response

Question 32

speed of absorption depends on ____

Answer 32

blood flow. This is why IM injections are more readily absborbed than SQ

Question 33

What is Vd?

Answer 33

The theoretical volume that would be needed to contain the total amount of administered drug at the initial concentration (C0) in the plasma after IV administration (or at Cmax after other forms of administration. Higher Vd means more distribution of the drug from the blood into the tissues, but not specific sites

Question 34

What does a higher Vd indicate?

Answer 34

more distribution of the drug from the blood into the tissues

Question 35

What is the clearance (Cl) of a drug after a single dose equal to?

Answer 35

dose/AUC

Question 36

What is a half life

Answer 36

the length of time it takes for the concentration of the drug in plasma to decrease by half (t1/2). When the dose is doubled, the duration of drug action is extended by 1 halflife

Question 37

What are the four physiological responses associated with pharmacokinetics

Answer 37

absorption distribution metabolism elimination