Pharmacokinetics and Pharmacology Review

Question 1

pharmacodynamics

Answer 1

the drug’s effect on the body, therapeutic and toxic

Question 2

agonist

Answer 2

substance that binds to a specific receptor and triggers a response in the cell.

mimics the actin of an endogenous ligand that binds to the same receptor

Question 3

Full agonist

Answer 3

maximal activation of all receptors

Question 4

partial agonist

Answer 4

can block some receptors while effecting other receptors
agonist-antagonist - have both agonist and antagonist effects
activates a receptor but cant produce a maximum response

Question 5

antagonist

Answer 5

• drug that has affinity for the receptor but no efficacy
• combination with receptor may block a response
• higher affinity for receptor

Question 6

physiologic antagonism

Answer 6

two agonists drugs that bind to different receptors causing opposing responses

ex: phenylephrine vs cardene

Question 7

chemical antagonism

Answer 7

no receptor activity is involved. One drug binds with the second drug to inactivate it

ex: protamine and heparin

Question 8

receptor

Answer 8

the component of a cell that interacts with a drug and initiates the chain of events leading to the drug’s effect

-may be membrane bound, intracellular proteins (caffeine, insulin, steroids, theophylline, milrinone), or circulating proteins (coag cascade)

Question 9

affinity

Answer 9

the degree of drug receptor interaction for a given drug - potency -

Question 10

efficacy

Answer 10

-intrinsic activity- a drug’s ability to produce the desired response expected by stimulation of a given receptor, the max effect that can be achieved with the drug

Question 11

spare receptor concept

Answer 11

not all receptors have to be covered to work

-maximal or nearly maximal response can often be produced by activations of only a fraction of the receptors present

Question 12

down regulation

Answer 12

desensitization - occurs with continued stimulation of cells with agonists - the effect is diminished

ex: beta agonist bronchodilators - tolerance develops from repeated use, increased dose will be required

Question 13

up regulation

Answer 13

chronic exposure to antagonists cause receptor number and sensitivity to increase

ex: beta blockers

Question 14

drugs that don’t act on proteins

Answer 14

sodium citrate
chelating drugs
iodine
sodium bicarb

Question 15

What causes variability of pharmacologic response

Answer 15

age
sex
body weight - kg and ideal body weight
body surface area
basal metabolic rate - temp affects
pathologic state
genetic profile

Question 16

pharmicokinetics

Answer 16

the actions of the body on the drug

absorption, distribution, metabolism, elimination

Question 17

absorption

Answer 17

Route - PO, IM, IV, rectal

first pass effect - PO and rectal pass through liver first which extracts and/or metabolizes some of the drug

Question 18

bioavailability

Answer 18

the extent to which a drug reaches it effect site after its introduction into the circulatory system
affected by lipid solubility, solubility in aqueous and organic solvents, molecular weight, pH, pKa, and blood flow

Question 19

distribution

Answer 19

(alpha phase) the plasma concentration of the drug declines

Question 20

two compartment model

Answer 20

distribution phase – decrease in plasma level – elimination phase

Question 21

redistribution

Answer 21

termination of effect
plasma level decreases to the point that the drug moves out of the vessel rich central group and is then taken into the peripheral group

Question 22

elimination

Answer 22

beta phase

involves metabolism and excretion, clearance of drug

Question 23

Vessel rich

Answer 23

brain, heart, liver, kidney, endocrine

receives 75% of cardiac output (only 10% body mass)

Question 24

lean muscle

Answer 24

muscle and skin

receives 19% of cardiac output (50% body mass)

Question 25

fat

Answer 25

receives 6% of cardiac output (20% body mass)

Question 26

vessel poor

Answer 26

bone ligament and cartilage | receives 0% of cardiac output (20% body mass)

Question 27

metabolism pathways

Answer 27

oxidation reduction hydrolysis conjugation

Question 28

Phase 1 metabolism

Answer 28

oxidation, reduction, hydrolysis | increases the drugs polarity

Question 29

phase 2 metabolism

Answer 29

conjugation drug or metabolites are covalently linked to a highly ionized molecule the resulting conjugate is more water soluble for excretion

Question 30

sites of metabolism

Answer 30

``` hepatic microsomal enzymes plasma - hoffmann elimination lungs kidneys GI tract ```

Question 31

cytochrome P450 enzymes

Answer 31

hepatic microsomal enzymes mostly | oxidative metabolism of most drugs

Question 32

enzyme induction

Answer 32

the ability of drugs or chemicals to stimulate activity of the cytochrome p450 system may be due to increased synthesis of cytochrome p450 and cyt p450 reductase can be revved up

Question 33

noncytochrome p450 enzymes (esters)

Answer 33

nonmicrosomal enzymes metabolism by conjugation, hydrolysis, and some oxidation and reduction largely in liver and some GI not inducable, genetically determined.

Question 34

phase 1 enzymes

Answer 34

cytochrome p450 nonmicrosomal enzymes noncytochrome p450 enzymes (esters)

Question 35

phase 2 enzymes

Answer 35

glucoronosyltransferases gluthathione-s-transferases n-acetyl-transferases sulfotransferases

Question 36

what meds metabolized by glucoronosyltransferase

Answer 36

morphine, propofol, and midalozam

Question 37

n-acetyl-transferases

Answer 37

have fast and slow acetylators | slow acetylators are at greater risk for side effects because you dont metabolize drugs as fast

Question 38

gluthione-s-transferases

Answer 38

a defensive system for detoxification and protection against oxidative stress

Question 39

elimination 1/2 life

Answer 39

the time for the drug in the plasma to decrease by 50% affected by volume of distribution and changes in clearance

Question 40

context sensitive half time

Answer 40

the time for the plasma drug concentration to decrease 50% after discontinuing a continuous infusion of a specific duration (the longer the infusion the longer the half time)

Question 41

effect-site equilibration time

Answer 41

the time between IV injection into the plasma and the delivery of the drug to its site of action important to consider for redosing, don't want to redose if drug hasn't made it to site of side effect

Question 42

volume of distribution

Answer 42

number to describe the apparent volumes of compartments that constitute the compartmental model. Dose of drug given divided by the amount in plasma prior to elimination.

Question 43

volume of distribution (Vd) effected by

Answer 43

lipid solubility binding to plasma proteins molecular size

Question 44

ionized

Answer 44

water soluble, poorly lipid soluble ex: Neuromuscular blockers

Question 45

non-ionized

Answer 45

lipid soluble, diffuses easily across lipid barriers like blood-brain barrier, GI endothelium, hepatocytes, renal tubular epithelium, placenta

Question 46

protein binding

Answer 46

effects distribution of drugs as only unbound drug can cross cell membranes

Question 47

agonist + agonist

Answer 47

1+1=2 | ex nitrous and sevo

Question 48

synergistic

Answer 48

1+1=3 | ex: fentanyl and benzos (increases impact of resp depression, sedation)

Question 49

potentiation

Answer 49

1+0=3 | enhancement of one drug action by second drug with no action of its own

Question 50

antagonistic

Answer 50

1+1=0 | ex: fentanyl + narcan

Question 51

hyperreactive

Answer 51

having or showing abnormally high sensitivity to stimuli ex: vasodilators and dehydration

Question 52

hypersensitive

Answer 52

abnormally susceptible physiologically to a specific agent | typically immune mediated response

Question 53

hyporeactive

Answer 53

having or showing abnormally low sensitivity to stimuli

Question 54

safety margin

Answer 54

therapeutic vs lethal dose

Question 55

tolerance

Answer 55

the capacity of the body to endure or become less responsive to a substance (as a drug) or a physiological insult especially with repeated use or exposure

Question 56

tachyphylaxis

Answer 56

diminished response to later increments in a sequence of applications of a physiologically active substance [med]

Question 57

Inverse agonist

Answer 57

A drug or endogenous chemical that binds to a receptor, resulting in the opposite action of an agonist. May have a theoretical advantage over antagonists in situations in which a disease state is partly due to an up regulation of receptor activity,

Question 58

Ligand

Answer 58

Molecule that is able to bind and form a complex with a receptor to produce a biological response. Are endogenous chemicals

Question 59

Quantal drug response

Answer 59

Using dose response curves, the actions of a drug can be quantified and expressed as the effective dose ED50, toxic dose TD50, and lethal dose LD50. The therapeutic index is LD50/ED50

Question 60

Ceiling effect

Answer 60

Refers to the dose beyond which there is no increase in effect. Additional dosing often leads to adverse effects.