Exam 1 - Pharmacokinetics Flashcards

1
Q

Steady State Concentration

A

Constant serum concentration that is achieved when rate of drug administration = rate of drug metabolism/excretion

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2
Q

What is steady state concentration used for?

A

Assess patient response, make new decisions

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3
Q

Linear pharmacokinetics

A

Steady state concentrations increase/decrease proportionally according to dose. Example: Vancomycin, procainamide

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4
Q

Linear pharmacokinetics - not applicable when?

A

Patient has renal failure, organ failure, etc.

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5
Q

Non-linear pharmacokinetics

A

Steady state concentrations change in disproportionate fashion after dose is changed

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6
Q

Valproic acid, carbamazepine, phenytoin have what type of pharmacokinetics?

A

Non-linear

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7
Q

Saturable or Michaelis-Menten Pharmacokinetics

A

Steady state concentration increases more than expected after dose increase. Number of drug molecules overwhelms enzymes ability to metabolize drug

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8
Q

Half life

A

Time required for serum concentrations to decrease 50% during elimination phase after absorption/distribution are complete

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9
Q

How long does it take to reach steady-state concentrations during continuous dosing?

A

3-5 half lives

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10
Q

A faster clearance will cause a _____ half life

A

Shorter (if kidney function picks up, half life will be shorter)

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11
Q

Larger volume of distribution will result in ____ half life

A

Longer (amiodarone) or shorter (propofol)

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12
Q

Bioavailability

A

Fraction of administered drug that is delivered to systemic circulation

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13
Q

Bioavailability of IV drugs

A

100%

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14
Q

Central compartment

A

Plasma

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15
Q

Peripheral compartment

A

Tissues

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16
Q

Multi compartment model

A

Body is central compartment where drug is administered, peripheral compartment is where drug is distributed - curvature will be non linear.

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17
Q

Back end kinetics

A

Describes how plasma drug concentrations decrease once a continuous infusion is terminated

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18
Q

Decrement time

A

Predicts the time required to reach a certain plasma concentration once infusion is terminated

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19
Q

If decrement time is 50%, what is another name?

A

Context sensitive half time

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20
Q

Longer infusion will result in ______ decrement time

A

Prolonged — due to increased accumulation

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21
Q

Effect site

A

Biophase - drugs exert their biological effect at this site

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22
Q

Biophase

A

Body compartment in which receptor sites reside

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23
Q

Pharmacokinetics

A

Relationship between the drug administration and drug concentration at the site of action. Movement of drug throughout the body

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24
Q

Pharmacokinetics principles

A

ADME - Absorption, distribution metabolism, excretion/elimination

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25
Q

Magnitude of drug effect and duration of action is affected by?

A

Absorption

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26
Q

Percent of drug that reaches systemic circulation

A

Bioavailability

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27
Q

Volume of distribution equation

A

Dose divided by concentration

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28
Q

A larger person will have a _______ volume of distribution

A

Larger

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29
Q

A smaller person will have a _______ volume of distribution

A

Smaller

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30
Q

When does volume of distribution increase?

A

When drugs move from blood to tissues

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31
Q

As volume of distribution increases due to drugs moving from blood to tissues, what will happen to blood concentration?

A

Decreases

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32
Q

Redistribution

A

Drug will distribute from organ back to blood once concentration in organ exceeds blood. Once in the blood, the drug will redistribute to other tissues that are still up taking the drug

33
Q

Highly lipophilic drugs leads to ________ in brain concentration and redistribution to muscle

A

Decrease

34
Q

Critically ill patient has _____ albumin, which causes fraction unbound drug to _______, leading to _________ volume of distribution

A

Decreased, increased, increased

35
Q

Unbound drug can or cannot cause a clinical effect?

A

Can

36
Q

If fraction of unbound drug decreases, what will happen to volume of distribution?

A

Decrease

37
Q

Drugs highly bound to albumin - part 1

A

Propofol
Morphine
Propranolol
Verapamil

38
Q

Drugs highly bound to albumin - part 2

A

Aspirin
Carvedilol
Omeprazole
Midazolam

39
Q

Drugs highly bound to albumin - part 3

A
Carbamazepine
Ceftriaxone
Dexamethasone
Diazepam
Itraconazole
Phenytoin
Valproic acid
Warfarin
Diltiazem
40
Q

AAG increases, fraction of unbound drug ______, volume of distribution _______

A

Decreases, decreases

41
Q

Drugs highly bound to AAG - part 1

A

Lidocaine
Fentanyl
Propranolol
Verapamil

42
Q

Drugs highly bound to AAG - part 2

A

Midazolam

43
Q

Drugs highly bound to AAG - part 3

A

Carbamazepine

Diltiazem

44
Q

Increase in total body water due to IVF will increase volume of distribution for what type of drugs?

A

Hydrophilic - decreased serum concentration

45
Q

Intrinsic clearance is expressed as?

A

Volume per unit of time (mL/hour)

46
Q

Drugs excreted unchanged in urine/stool are ______philic

A

Hydrophilic

47
Q

Drugs that are not very _______philic are converted into more _____philic compounds for excretion

A

Hydrophilic, hydrophilic

48
Q

Phase I metabolism reactions are catalyze by what?

A

CYP450

49
Q

High concentrations of CYP enzymes are found in

A

Smooth endoplasmic reticulum of hepatocytes

Membranes of upper intestinal enterocytes

50
Q

Lower concentrations of CYP enzymes are found

A

Lungs
Kidneys
Skin

51
Q

Inhibitors or inducers of CYP3A4 will cause what to occur

A

Inhibition of metabolism or induction (causing) of metabolism

52
Q

Most common CYP450 enzyme

A

CYP3A4

53
Q

CYP3A4 accounts for ______% of all CYP mediated drug metabolism

A

40-45

54
Q

CYP inducers result in _____ metabolism

A

Increased

55
Q

CYP inhibitors result in ________ metabolism

A

Decrease

56
Q

CYP inducers

A

St. John’s wort, rifampin, phenytoin, carbamazepine, phenobarbital

57
Q

CYP inhibitors that decrease metabolism

A
Amiodarone
Cimetidine
Clarithromycin
Diltiazem
Erythromycin
Grapefruit juice
Fluconazole
Isoniazid
Ritonavir
Verapamil
58
Q

Hydrolysis occurs in which drugs?

A

Remifentanyl, succinylcholine, esmolol, ester local anesthetics

59
Q

Type of reaction that does not involve CYP system and metabolizes drugs

A

Hydrolysis

60
Q

Phase II of biotransformation

A

Transforms hydrophobic molecules into water soluble molecules thru addition of polar groups; form glucuronides, acetates, or sulfates

61
Q

Drugs that undergo phase II conjugation

A

Propofol, morphine, midazolam

62
Q

Hypermetabolism may occur in which patients?

A

Febrile, traumatic brain injury

63
Q

Hypo-metabolism will occur in which patients?

A

Hepatic failure, kidney injury, hypothermic,

64
Q

Hepatic clearance equation

A

Hepatic clearance (CLh) = Extraction ratio * Hepatic Blood Flow

65
Q

Hepatic extraction ratio

A

Fraction of drug removed during one pass through liver

66
Q

Hepatic extraction ratio - Low

A

0 - 0.3

67
Q

Hepatic extraction ratio = 0

A

Liver does not metabolize the drug

68
Q

Hepatic extraction ratio - intermediate

A

0.3-0.7

69
Q

Hepatic extraction ratio - high

A

> 0.7

70
Q

Hepatic extraction ratio = 1

A

Hepatic metabolism entirely dependent on blood flow

71
Q

Pharmacodynamics

A

Relationship between drug concentration and biochemical/physiologic effect on body

72
Q

What type of drug is Narcan?

A

Competitive antagonist

73
Q

Up regulation

A

Number of receptors increases

74
Q

Down regulation

A

Number of receptors decrease

75
Q

Tachyphylaxis

A

Tolerance - decreased response to same amount of agonists

76
Q

Agonist-antagonist

A

Partial agonists that have antagonist activity

77
Q

ED50

A

Potency

78
Q

ED50

A

Dose required for desired effect in 50% of population exposed to it

79
Q

Therapeutic drug monitoring is a measure of pharmaco_______

A

Pharmacodynamics