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Flashcards in Pharmacology Deck (107):
1

What are the 5 key elements in pharmacotherapeutics?

1. drug
2. dose
3. route
4. frequency
5. duration

2

What pharmacologic principle are drug and dose based on?

Pharmacodynamics -
disease targets and drugregulation

3

What pharmacologic principle are route and frequency based on?

Pharmacokinetics

route - AD
frequency - ME

4

What pharmacologic principle is duration based on?

Disease pathophysiology

5

What are 4 basic drug categories?

1. prescriptions
2. controlled substances
3. OTC
4. Dietary supplements

6

What phase is clinical testing starts comparing drugs to placebos or existing treatments?

Phase II

7

What phase of clinical testing do most drugs fail?

Phase III

8

What phase of clinical testing do you monitor "does it work?"

Phase II and III

9

If you have a drug similar to one that is already approved, what application do you use to bypass testing trials?

abbreviated new drug application (ANDA)

10

Do structure/function claims require FDA approval?

No, but needs a disclaimer.

only health claims do require FDA approval

11

What are the 3 different FDA categories of drug equivalency?

1. pharmaceutical equivalents
2. bioequivalent
3. therapeutic equivalent

12

What does signa or "sig" indicate on a prescription pad?

drug directions to pts.
aka dosage regimen

13

Manufacturer distribution of depressants and stimulants are divided into 5 ______

schedules

14

The 5 schedules I-V are in order from (lower to higher) abuse potential or (higher to lower) abuse potential

higher to lower abuse potential

Schedule I - no medical use, high abuse potential

15

How many mg make 1 grain?

65 mg = 1 grain

16

How many grams make 1 ounce?

28.4g = 1 oz

17

how many grams in 1 lb?

454g = 1 lb

18

how many ml make 1 tsp?

5 ml = 1 tsp

19

how many ml make 1 tablespoon?

15ml = 1 tablespoon

20

how many ml make 1 oz?

30ml = 1 oz

21

What does od* and os stand for?

right eye, left eye

22

What is the relationship between Cp and Vd?

inverse

more drug in plasma = less being distributed

23

Higher volume of distribution = more/less lipid soluble drug?

more lipid soluble

24

drug formulations must be more hydrophilic/hydrophobic to dissolve and release molecule?

hydrophilic

25

drug molecule must be more lipophilic/lipophobic to cross membrane?

lipophilic

26

after drug gets metabolized by liver it becomes more/less water soluble?

more water soluble

27

The more unionized a drug, the more/less lipid soluble it is.

More

More unionized = more lipid soluble

28

P-glycoproteins move drugs from the _______ space to the ______ space

intracellular, extracellular

(Inside-> out)

29

Bioavailability is termined by comparing AUC following single/multiple dose of a drug following IV route?

single

30

What is another word for extravascular?

Interstitial

31

High Vd indicates drugs are mostly located where?

Low Vd?

High Vd = outside plasma


low vd = inthe plasma or ECF

32

What is the term for the route of drugs that are taken into the body other than through the digestive tract?

Parenteral

33

If Vd is 3L, where are the drugs mostly located?

restricted to plasma

34

Extracellular water is ~12ml. What two compartments make up that volume?

plasma = 3L
Interstitial = 9L

(highly bound to plasma proteins)

35

If Vd is 12 L, where are the drugs mostly located?

In the extracellular compartment (plasma and interstitial)

(enters cells poorly)

36

If Vd is 41L, where are drugs mainly located?

Total body water

(freely enter cells)

37

If Vd >? 50L, where are drugs mainly located?

sequestered in CNS, fat

38

When weak acids are protonated, it is ionized/unionized.

This means it can/cannot cross biological membranes.

unionized


can - absorbed

39

Acids become nonionized in acid/base medium.

acid

(lots of H, so it holds onto proton)

40

When weak bases are protonated, it is ionized/unionized.

This means it can/cannot cross biological membranes.

ionized (ie: NH3+)

cannot (ion trapped)

41

Ion trapped means what?

Drug has been ionized and can no longer cross membrane.

42

What is the henderson hasselbach equation?

pH-pKa = log [non-protonated/protonated]

or 10^(pH-pKa)


n before p

43

What does it mean when pH of biologic compartment is < pKa of drug?

more protons are present,

there will be more protonated forms of both acid and base.

44

When pH>pKa, what does it mean?

fewer protons present

there will be more unprotonated forms of acid and base

45

greater [ ] of drug is greater on side where ionization is greater/lesser?

greater

• Acidic drugs are trapped in the more basic solutions
• Basic drugs are trapped in the more acidic solutions

46

3 types of membrane compartments that act as special barriers?

1. GI mucosa
- negligible absorption of drug into blood
2. BBB
3. Renal tubules

47

Binding of drugs to plasma proteins prolongs/reduces drug action

prolongs -

hinders metabolic degredation, and reduce rate of excretion.

48

How are plasma proteins a potential source of DDI?

They are important in drugs with narrow therapeutic index.

49

What is biotransformation?

drug metabolism

enzyme catalyzed chemical structure transormation via liver

50

What is the most frequent pathway of biotransformation (drug metabolism)?

oxidation

51

The liver makes _____ compounds converted to _____ compounds to be more readily excreted.

lipid soluble, --> water soluble

52

Phase I reactions include:

oxidation
reduction
hydrolysis

53

2 types of Phase I oxidation reactions

1. cytochrome p450 dependent

2. cytochrome p450 independent

54

Cyt p450 dependent oxidation
1. found where?
2. involves enzymes or cofactors?

1. rich in liver
2. cofactors

55

Cyt p450 independent oxidation
-what enzymes are involved?

1. amine oxidases
2. dehydrogenases

56

In phase I hydrolysis, what enzymes are involved?

esterases, amidases

57

Which phase reactions are more prone to:
1. inhibition of drug metabolism?
2. DDI?
3. age related changes?

all Phase I

58

What phase reaction are more prone to saturation?

phase II

59

Inducers do what?

increases drug metabolism via cyt p450 system

60

What do inhibitors do?

decreases drug metabolism and causing decrease drug clearance

61

Name some inducers

1. phenobarbitol
2. phenotoin
3. rifampin
4. ethanol
5. carbamazepine
6. st. John's wort

62

Name some inhibitors

1. cimetidine
2. grapefruitjuice
3. HIV protease inhibitors
4. erythromycin
5. ketoconazole
6. fluoxetine

63

How does the kidney work in drug excretion?

via filtration, secretion, reabsorption

64

How fast is drug clearance in:
-filtration
-active tubular secretion
-tubular reabsorption

120 ml/min

120-600ml/min

1ml/min

65

Kidney filtration or secretion is highly affected by plasma protein binding and requires free, unbound drugs?

filtration

66

Kidney tubular secretion process/movement

drugs are transported directly from blood into urine.

67

Kidney tubule reabsorption

reabsorption of lipid-soluble drugs (via passive diffusion of the proximal and distal tubes)

(water soluble metabolite less likely to be reabsorbed. Remember that the liver makes drugs MORE water soluble to be excreted)

68

Describe the enterohepatic cycle

Drugs are excreted via bile --> bile duct --> SI --> reabsorbed into blood --> liver

69

First order kinetics rate of elimination vs Zero order

First order: rate of elimination is proportional to [ ] of drug in plasma Cp

Zero order: rate of elimination is constant and independent of amt of drug in body

70

When is first order kinetics used to eliminate drugs vs zero order?

Most drugs eliminated via first order kinetics

- drugs will be removed due to zero order kinetics when hepatic metabolic enzyme systems are saturated

71

Two types of receptors? examples

1. generalized receptors
- biological molecules
2. specialized receptors
- membrane proteins, ion channels

72

Signal transduction and amplification can activate what 3 things?

1. ligand-gated ion channel
2. GPCR
3. Kinase-linked
receptor/hormone (nuclear) receptor

73

What is response [E] of a drug proportional to?

receptors[R] occupied by drug [D]

74

Explain what a dose response curve indicate?

hyperbolic

-at low doses, drug response increases proportionally to dose
- curve levels off bc there is a limit to response achieved

75

Explain what a log dose-response curve indicate

sigmoid

can compare different drugs (and wide range of doses)
- straight line corresponds to therapeutic range

76

What is potency?

EC50 or ED50

concentration or dose required to produce 50% of drugs maximal effect

-more potent, takes less to bring about EC50 or ED50

77

What is efficacy?

ability to initiate response
-most important determinant of clinical usefulness

78

Competitive reversible antagonist affects potency/efficacy

it decreases potency

(doesnt affect# of receptors available to contribute to response)

79

Non competitive "reversible" antagonists affects potency/efficacy

It decreases efficacy (Emax goes down)

80

Two types of noncompetitive antagonist

1. binds to active site
2. binds to allosteric site

81

Two types of noncompetitive active site antagonist?

1. irreversible
2. pseudoirreversible

82

What are reversible antagonists that bind to the active site of the same receptor?

competitive "reversible" antagonist

83

Two types of noncompetitive allosteric site antagonist?

1. reversible
2. irreversible

84

What is ED50 for graded dose-response curve?

dose that produces 50% of maximal response possible

85

What is ED50 for population dose-response curve?

effective dose that initiates target response in 50% of pop

86

Higher therapeutic index indicates what?

safer drug
(usual clinical drugs between 10-20)

87

FDA categories for Drug use in pregnancy: description of -
A

shows no risk

88

FDA categories for Drug use in pregnancy: description of -
B

no evidence of risk

89

FDA categories for Drug use in pregnancy: description of -
C

risk cannot be rule out

90

FDA categories for Drug use in pregnancy: description of -
D

positibe evidence of human fetal risk

91

FDA categories for Drug use in pregnancy: description of -
X

contraindicated in pregnancy

DO NOT USE

92

What are the 4 pharmacokinetic interventions preventing drug overdoses and poisoning?

1. Prevent absorption of toxin
2. Inhibit toxication
3. Enhance metabolism
4. Increase elimination of toxin

93

4 ways to prevent absorption of toxin

1. Emesis
2. Gastic lavage
3. Chemical adsorption
4. osmotic cathartics

94

Important drugs for emesis

1. Ipecac
2. Apomorphine

95

Contraindications for ipecac or apomorphine

§ Patient comatose / stuporous (lack of gag reflex à risk of aspiration)

§ Ingestion of corrosive poisons (i.e., strong acids or alkalis)

§ Ingestion of CNS stimulant such as strychnine (risk of seizures)

§ Ingestion of petroleum distillate (risk of pneumonitis)

§ Pregnancy Category C: (weigh benefit vs risk, unknown if drug can cause harm)

96

What is chemical adsorption

an emesis intervention used to prevent absorption of toxin:

binds drug in gut - limits adsorption

97

What is osmotic cathartics?

an emesis intervention used to prevent absorption:

decreases time of toxin in GI tract if ingestion is >60

98

Recommended drugs for osmotic cathartics?

sorbitol,
Mg citrate or sulfate
polyethylene glycol

99

3 methods used to inhibit toxication (pharmacokinetic interventions)

1. inhibit rate limiting enzyme
2. hemodialysis
3. sodium bicarb (corrects metabolic acidosis)

100

4 methods used to increase elimination of toxin

1. extracorporeal removal
2. enhanced metabolism
3. enhanced renal excretion
4. chelation of heavy metals

101

how is 70-80% of Acetaminophen (AC) metabolized?

conjugated with glucuronic acid or sulfate (phase II)

102

5-10% of acetaminophen is metabolized how? describe

5-10% of AC proceeds through cytochrome P450 oxidation (phase I)

AC → becomes chemically reactive NAPQI (Ac*)
→ becomes detoxified by phase II GSH
transferase
→ excreted as mercapturate

103

Describe mechanism of acetaminophen overdose toxicity

= hepatocellular injury due to saturation

-Saturation of Phase II conjugation pathways ←glucuronide + sulfate→

-This leads to excessive formation of Ac* by phase I pathway

-Glutathione (GSH?) gets depleted

- Ac* builds up

104

Describe acetaminophen treatment.

N- acetylcysteine (mucomyst)
-glutathione synthesis

105

What is methanol (CH3OH) metabolized to?
poisoning leads to what?

formic acid

○ Visual disturbance (snowstorm) soon after acidosis → cant breath → die

106

What is ethylene glycol (HOCH2CH2OH) metabolized to?
Leads to what?

oxalic acid

○ Acute renal failure

107

What is the rate limiting enzyme in methanol and ethylene glucol metabolism?

-how can you inhibit it?

alcohol dehydrogenase

ihibit with fomepizole