Therapeutic Drug Monitoring Flashcards

1
Q

What is therapeutic drug monitoring?

A

the measurement of drugs and/or their metabolites in body fluids-usually blood-to maintain therapeutic benefits

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2
Q

What is the definition of drugs (for the purpose of this class)?

A

medications that are prescribed by medical providers

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3
Q

What is the definition of therapeutic range (TR)?

A

the dose, or concentration, range of a drug within which the drug produces the desired therapeutic effect​

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4
Q

What is the result if a drug is outside of the therapeutic range?

A

Inefficacy or toxicity

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5
Q

What are the two main purposes of TDM?

A
  • Ensure correct drug dosages for the T.R.​
  • Identify drug-drug interactions if multiple drugs are taken together
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6
Q

When would TDM be appropriate for a drug?

A
  • The drug has a narrow therapeutic range
  • Marled pharmacokinetic variabilities
  • Critical adverse effects
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7
Q

All of the following are what?

Age​

Gender​

Genetics​

Diet​

Co-administered drugs​

Naturopathic agents

A

Factors that influence drug concentrations and efficacy

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8
Q

Define pharmacokinetics

A

Study of the movement of drugs in the body

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9
Q

What does pharmacokinetics tell us?

A

Provides a time-course of drug concentrations in the body as a function of absorption, distribution, metabolism, and excretion

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10
Q

What is bioavailability?

A

The fraction of the administered dose that eventually reaches its site of action​

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11
Q

The following are all examples of what?

Oral—most common, least invasive​

Intravenous (IV)—most direct & effective​

Intramuscular (IM)​

Subcutaneous (SC)​

Aerosol​

Transdermal patch​

Rectal

A

Routes of administration

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12
Q

What are the three factors that effect the efficiency of absorption from GI tract?

A
  • Dissociation from its administered form​
  • Solubility in GI fluids​
  • Diffusion across GI membranes
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13
Q

T/F:

In order for a drug to passively diffuse from the GI tract to the bloodstream, it must be in the hydrophilic state.

A

FALSE

The drug must be in the hydrophobic state (nonionized)

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14
Q

Drugs will be absorbed in the GI tract ____ in healthy people.

A

Predictably

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15
Q

Weak acids are efficiently absorbed by the __a__; weak bases are absorbed in the __b__

A

a) Stomach

b) intestine

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16
Q

Drug absorption is affected by what?

A

Changes in intestinal motility, pH, inflammation

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17
Q

T/F:

Absorption is not changed wen someone is getting older, becomes pregnant, or develops a pathological condition.

A

FALSE

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18
Q

What is the definition of drug distribution?

A

The movement of a drug between blood circulation and tissues and organs and the relative proportion of the drug in the tissues​

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19
Q

____ ____ affects the ability of a drug to leave circulation

A

Lipid Solubility

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20
Q

What is a free fraction?

A

The portion of a drug that exerts a pharmacologic effect​

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21
Q

Free fractions can diffuse out of the __a__ and into the __b__ and __c__ spaces.

A

a) vasculature

b) interstitial

c) intracellular

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22
Q

What is the formula for drug distribution?

A

The volume of distribution of a drug = (dose of the drug) / (concentration of the drug​)

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23
Q

The following are characteristics of what protein?

Majority of plasma protein constituents​

Major transporter of drugs​

Changes in concentration affects free vs bound

A

Albumin

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24
Q

T/F:

Most drugs are subject to binding with serum protein constituents to form drug-protein complexes

A

TRUE

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25
Q

Only ________ fractions can interact with the site of action to result in a biologic response

A

Free/unbound

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26
Q

All drugs absorbed from the intestine (except rectum) enter what system?

A

Hepatic portal system

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27
Q

What is the first pass effect?

A

The phenomenon in which a drug is metabolized, results in a reduced concentration o the drug before reaching the circulatory system

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28
Q

What are the consequences of impaired liver function?

A
  • Reduced ability to metabolize
  • Effects ability to perform biotransformation to produce the therapeutically active metabolite of the drug
  • May require dosing adjustments
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29
Q

What are xenobiotics?

A

Makes up the most drugs. They are exogenous substances capable of entering biochemical pathways that are meant for endogenous substances

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30
Q

_____ is the biochemical pathway responsible for a large portion of drug metabolism​

A

Hepatic mixed function oxidase (MFO) systems

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31
Q

What are the two basic function of MFO?

A
  • Involves taking hydrophobic substances & through a series of enzymatic reaction, converts them to water soluble products​
  • Products can then be transported into the bile or released into general circulation for elimination by renal filtration
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32
Q

Result of Phase 1 reactions in MFO

A

To produce reactive intermediates

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33
Q

Result of Phase 2 reactions in MFO

A

Conjugate functional groups to reactive sites in water-soluble products

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34
Q

T/F:

Drug elimination is dependent on the clearance mechanism

A

FALSE:

Independent of clearance mechanism, decreases in the plasma drug concentration most often occur as a first-order process

35
Q

For drugs not secreted or reabsorbed, the elimination rate directly relates to ____

A

Glomerular Filtration Rate (GFR)

A decreased GFR results in increased half life and plasma concentration

36
Q

Many drugs metabolized in the liver are excreted in ____

A

Bile

37
Q

T/F:

When administering drugs on a schedule, you only want the peak blood drug concentration to be in the therapeutic range

A

FALSE

You want to have both peak and trough concentrations to be in the therapeutic range

38
Q

How many doses are typically needed to reach a steady-state oscillation?

A

5-7 doses

39
Q

What is the definition of pharmacodynamics?

A
  • The study of the biochemical and physiological effects of drugs and their mechanisms of action​
  • Describes the relationship between a drug’s concentration at its site of action and its pharmacological responses​
40
Q

What is the single most important factor of specimen collection?

A

Accurate timing of specimen collection

41
Q

When is the trough typically drawn?

A

Right before the next dose or random

42
Q

If on oral meds, when is the peak drawn?

A

1 hour post oral dose

43
Q

If on V medication, when is the peak drawn?

A

90 min post IV dose

44
Q

T/F:

You want to draw peaks only after that 5-7 dose steady oscillation is achieved

A

TRUE

45
Q

What tube is preferred for medication testing?

A

Serum (RED)– NO GEL as it may interfere

46
Q

What tube do you collect for immunosuppressive drug testing?

A

EDTA WB

47
Q

What is the definition of pharmacogenomics?

A

The science of studying variations and developing drug therapies to compensate for the genetic differences impacting therapy regimens​

48
Q

What is the difference between a responder and a nonresponder?

A

Responders will have the benefits of the therapeutic/desired effects of a drug while Nonresponders do not.

49
Q

What is the prominent gene that affects drug metabolism?

A

Cytochrome P450 (CYP450)

50
Q

What does CYP450 tell us?

A

Indicates which drug would work best, predicts interactions, or if there would be a benefit

51
Q

Digoxin

A

One of the most common cardioactive drugs.

It is a cardiac glycoside and treats arrythmias and CHF.

Inhibits membrane Na-K-ATPase

LONG half live as once it is in the tissues it stays

52
Q

Quinidine

A

Cardioactive Drug

Natural from bark to treat arrythmias

53
Q

Disopyramide

A

Cardioactive Drug

Substitute for Quinidine

54
Q

Procainamide and N-Acetylprocainamide

A

Cardioactive Drug

55
Q

What is NAPA?

A

Cardioactive Drug

The hepatic metabolite of procainamide that works similarly to parent drug

56
Q

Aminoglycosides

A

Antibiotic

Treats gram neg and gram pos infections

Inhibits bacterial protein synthesis

57
Q

Gentamicin

A

Antibiotic

Treats GNR - life threatening

58
Q

T/F:

Nephrotoxicity is always reversible without compromising renal function

A

FALSE

Nephrotoxicity is USUALLY reversible but it CAN CAUSE renal failure

59
Q

T/F:

Ototoxicity is irreversible

A

TRUE

60
Q

Tobramycin

A

Antibiotic

Treats GNR

Ototoxic and nephrotxic

61
Q

Amikacin

A

Antibiotic

Treats severe blood infections

62
Q

Vancomycin

A

Antibiotic

Glycopeptide antibiotic

Against GPC and GPR

63
Q

What are adverse effects of vancomycin?

A
  • Redman syndrome (extremity flushing)
  • Nephrotoxicity
  • Ototoxicity
64
Q

Antiepileptic Drugs (AEDs)

A

Treat and suppress seizures

Only effective while drug metabolites are in the body

TDM is critical

65
Q

Primidone

A

AED

grand mal seizure– when resistance to other AEDs

66
Q

Phenobarbitol

A

AED

67
Q

Phenytoin and Free Phenytoin

A

AED

Common treatment for seizure disorder and short term prophylactic agent in brain injury

68
Q

What percentage do we have bound and free form of phenytoin and free phenytoin in the body?

A

90% bound form

10% free form

We need both in the body with some individualism as every body is different

69
Q

Carbamazepine (Tegretol)

A

AED

Severe adverse events (only use if nonresponsive to other AED)

70
Q

Valproic Acid (Depakote)

A

AED

71
Q

Gabapentin (Neurontin)

A

AED

Used for seizures and pain management

72
Q

Lithium

A

Psychoactive drug

Mood altering and used to treat bipolar, depression, aggresive/self-mutilatin, cluster headache, migraines

NO LIHEP TUBES

73
Q

Tricyclic Antidepressants (TCAs)

A

Psychoactive drug

Used to treat depression, insomnia, extreme apathy, loss of libido

74
Q

Clozapine (Clozaril, FazaClo)

A

Psychoactive drug

Treats refractory schizophrenia

75
Q

Olanzapine (Zyprexa)

A

Psychoactive drug

Treats schizophrenia, acute manic episodes, bipolar disorder

76
Q

Immunosuppressive Drugs

A

TDM used to monitor Immunosuppressive Drugs to prevent organ rejection

Most require est. of individual dosage regimens

77
Q

Clyclosporine

A

Immunosuppressive Drug

Suppress graft vs host rejection

78
Q

Tacrolimus FK-506

A

Immunosuppressive Drug

Oral, 100x more potent than cyclosporine

79
Q

Sirolimus

A

Immunosuppressive Drugs

Antifungal agent to prevent graft rejection in kidney transplants

80
Q

Everolimus

A

Immunosuppressive Drug

Derived from Sirolimus

Short half live results in a more rapid achievement of steady state pharmacokinetics

WB

81
Q

Mycophenolic Acid (MPA)

A

Immunosuppressive Drug

MPA is the active from of Mycophenolate mofetil which is a prodrug that rapidly converts to in the liver to MPA

82
Q

Antineoplastics

A

Pharmacodynamics are hard to est. so TDM isn’t as useful

Many rapidly metabolized or incorporated into cellular macromolecular structures​

Delivered dose more relevant than circulating concentrations​

83
Q

Methotrexate

A

Antineoplastic

TDM offers some benefits to est. therapeutic regimen

84
Q

Theophylline

A

Bronchodilator

Used to treat respiratory disorder