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Flashcards in Intro to Pharm Deck (92):
1

Agonist

binds to same site as ligand and makes same signal

2

Allosteric Agonist

binds to diff site than ligand
no signal
greater response than agonist

3

Partial Agonist

binds to same site
same signal
weaker response

4

Antagonist

same site
no signal
weaker response- inhibits agonist

5

Competitive Antagonist

reversibly bind
same site
receptor can reach max effect with enough agonist concentration

6

Non-competitive Antagonist

irreversibly bind
diff site
receptor cannot reach max effect

7

Therapeutic Index
TI

TD/ED
higher numbers = safer drug

8

Potency

concentration to produce 50% of max effect (EC50)

9

Efficacy

Emax
peak of dose-response relationship

10

Pharmacologic Antagonism

one receptor
responds to one drug while is inhibited by another

11

Chemical Antagonism

no receptor
2 drugs bind to each other and antagonize each other

12

Physiologic Antagonism

D1 affects R1, D2 affects R2
receptors oppose each other

13

Absorption

movement of drug from administration site to blood

14

Distribution

drug mvmt through blood throughout the body

15

Biotransformation

metabolism
drug converted to form where it is more easily eliminated

16

Elimination

excretion of drug from body

17

Oral Route

convenient but slow
subject to first pass effect

18

First Pass Effect

most of drug metabolized in liver before it reaches blood stream

19

Sublingual and Buccal

direct absorption into bloodstream

20

Intramuscular

fast absorption
can be given higher dose

21

Subcutaneous

slower absorption
can be given higher doses

22

Intravenous

NO ABSORPTION

23

Inhalation

Fastest absorption

24

Topical

for local effect

25

Transdermal

for systemic effect

26

Passive Diffusion

driven by concentration gradient- no E
no carrier- not saturable

27

Facilitated Diffusion

driven by concentration gradient- no E
carrier- saturable

28

Active Transport

against gradient- E needed
carrier- saturable

29

Charged or uncharged pass best through membranes?

uncharged

30

- pKa

acidic

31

+ pKa

basic

32

pKa

pH where 50% is ionized and 50% is nonionized

33

Lipid Soluble

nonionized

34

Water Soluble

ionized

35

Basic pH will do what to weak acids?

get rid of it

36

Basic pH will do what to weak bases?

keep it

37

Acidic pH will do what to weak bases?

get rid of it

38

Acidic pH will do what to weak acids?

keep it

39

pH of the Stomach

1

40

pH of the SI

6

41

pH of Blood

7.4

42

pH of Urine

5-8

43

pKa > pH

mainly HA and BH+

44

pKa < pH

mainly A- and B

45

pKa = pH

HA = A-
BH+ = B

46

Acidic Drugs

HA

47

Basic Drugs

BH+

48

Treatment for Hepatic Encephalopathy

Lactulose
fixes hyperammonemia

49

Lactulose

converts ammonia (NH3) to ammonium (NH4+)
turns GI basic

50

Weak acid overdose treated with....

bicarbonate
urine pH = 8

51

Weak base overdose treated with....

Ammonium chloride (NH4Cl)
urine pH = 5

52

Physical factors affecting absorption

blood flow to absorption site
surface area
contact time

53

Bioavailability

fraction of dose that reaches bloodstream
= Route/ Injected X 100

54

Factors affecting bioavailability

First pass hepatic metabolism (decreases)
solubility of drug (hyrophilic decreases)
chemical instability

55

Lag Time

time from administration to entrance into bloodstream
0 in IV

56

Onset of Activity

how long it takes for the drug to start working

57

Duration of Action

How long the drug works

58

Volume of Distribution
Vd

hypothetical volume of fluid in which a drug is disseminated
= amount of drug in body/ concentration in blood

59

High Vd

high volume of distribution
does not stay in blood

60

Low Vd

Low volume of distribution
drug stays in blood

61

Increasing Vd has what affect on half life?

increases it

62

Placenta and Drug Transfer

drugs cross by simple diffusion
lipid sol/ nonionized enter easily
NOT a barrier to drugs

63

Drug Metabolism

converting drug to an inactive form

64

Metabolism- Prodrugs

convert drugs to an active from

65

Benzodiazepine Metabolism

administered in an active for and its metabolites are active as well

66

Phase 1 Metabolism

uses cytochrome P450
in smooth ER
oxidation, reduction, hydrolysis

67

Phase 2 Metabolism

conjugation reactions
in cytoplasm
needs transferase enzymes
young kids can't do- drug accumulates

68

Conjugation Reaction

uses a transferase enzyme to attach a molecule from the body to the drug
makes the drug bigger and more likely to be eliminated (except in kids)

69

Liver

most important organ for drug metabolism

70

Cytochrome P450s that metabolize most drugs

CYP2C
CYP2D
CYP3A- 50% of all drugs

71

CYP Inducers

increase expression of p450s
speeds up metabolic process
reduce plasma lvls and effectiveness of drugs

72

Drugs that are CYP Inducers

benzopyrenes (cig smoke), chronic ethanol, carbamazepine, rifampin, phenytoin

73

CYP Inhibitors

decrease expression of P450s
slows metabolic process
increases plasma lvl and toxicity risk
bad when mixed with drugs w/ low TI

74

Drugs that are CYP Inhibitors

cimetidine, erythromycin, grapefruit juice

75

Glucuronidation

most common Phase 2
uses glucuronosyl transferase

76

Sulfation

Phase 2
uses sulfotransferase

77

Acetylation

Phase 2
uses acetyltransferase

78

Glomerular Filtration

only free, unbound drug filtered (too big)
lipid solubility and pH do not affect

79

Proximal Tubular Secretion

requires an OAT and OBT for drug secretion
undeveloped in young kids

80

Distal Tubular Reabsorption

drugs diffuse out into systemic circulation if they are uncharged
pH changes will increase ionized form/ decrease reabsorption/ increase elimination

81

First Order Kinetics

constant fraction is eliminated per unit time
half life constant
nonsaturating kinetics

82

Zero Order Kinetics

constant amount of drug is eliminated per unit time
half life not constant
saturating kinetics

83

Drugs that have zero order kinetics

aspirin
ethanol
phenytoin

84

Half Life Formula

0.693 x Vd / CL

85

Maintenance Dose

maintain plasma concentration of long period of time
chronic

86

Loading Dose

quickly increase blood plasma concentration
acute

87

Maintenance Dose Formula

= Css x CL / F
conc at steady state x clearance / bioavailabilty

88

Loading Dose Formula

= Css x Vd / F

89

When do you give a loading dose?

when a long time period is needed to reach steady state via continuous IV

90

Steady State

maintenance dose needed to reach and stay at

91

Clinical Steady State

4-5 half lives

92

Dosage Adjustment for Renal Failure

Correct Dose = ave dose x creatinine clearance / 100 mL/min