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Pharm Exam 1 - summer > Uptake & Distribution of IV Agents > Flashcards

Uptake & Distribution of IV Agents Flashcards

0
Q

What a drug does to the body?

-mechanism of effect, sensitivity, responsiveness (how responsive is the person to the drug that we are giving)

A

Pharmacodynamics

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1
Q

What the body does to a drug?

-absorption, distribution, metabolism, excretion

A

Pharmacokinetics

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2
Q

Commonly measured pharmacokinetic parameters of injected drugs are? (4)

A

Elimination half-time
Bioavailability
Clearance
Volume of distribution

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3
Q

1) Rate of transfer btw compartments decreases with ___, leading to greater plasma concentration in certain drugs (thiopental).
2) The more ___ the drug the easier it is for it to cross membranes and enter peripheral tissues.

A

1) Aging

2) lipid soluble

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4
Q

Distribution:
As the concentration of drug moves from the central compartment to the peripheral compartment. The ___ concentration increases and the ___ concentration decreases. This balance btw compartments will wax and wane until the drug is cleared. Although the distribution goes back and forth this does not mean the drug will continue to have the same effect.

A
  • peripheral

- plasma

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5
Q

The lung uptakes basic ___ drugs (???) and acts as a reservoir to release drug back into the systemic circulation.

*Give patient a dose of demerol and they say they are still having pain it is because it is still in their lungs. Give another drug but NOT demerol! The lung will give the drug back eventually.

A

Lipophilic

  • Lidocaine
  • Fentanyl
  • Demerol
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6
Q

The ___ is where the pain is and the brain (integration of pain information).

A

Effect site

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7
Q

CNS Distribution:

  • BBB prevents ___, ___ drugs from crossing the barrier into the brain circulation.
  • Blood Brain Barriers can be overcome with large doses of drug in ___ & ___.
A
  • ionized, water-soluble drugs

- head injury & hypoxemia

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8
Q

CNS Distribution:

1) ___ & ___ have a decreased BBB.
2) Typically only ___ drugs can cross the BBB.

A

1) Elderly & children

2) Lipophilic drugs

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9
Q

Drugs exert their biological effect at the ___ also called the ___. It is the immediate milieu where the drug acts upon the body, including membranes, receptors and enzymes.

A

Biophase

Effect site

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10
Q

What is the rate constant of drug elimination from the effect site?

A

Ke0

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11
Q

Sum of all the volumes of the compartments?

A

Volume of distribution

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12
Q

Vd is influenced by the physiochemical characteristics of the drug ???

A
  • Lipid solubility
  • Binding to plasma proteins
  • Molecular size
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13
Q

Volume of Distribution:
The more ___ the drug is the more easily it can cross the bilayer of membranes. Therefore it will have a ___ Vd.
Vd is ___ related to the ___ of the drug.

A
  • Lipid soluble
  • Large
  • Directly
  • Lipid solubility
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14
Q

Volume of Distribution:
Vd will be ___ due to binding of the drug to the plasma protein making it unable to cross membranes. As ___ drops more drug is released from the protein.
*The higher the protein binding of a drug the ___ the Vd.

A
  • Smaller
  • Plasma concentration
  • Lower
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15
Q

Volume of Distribution:

As molecular size increases the Vd ___.

A

Decreases

the smaller the molecule the easier it can pass thru a membrane

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16
Q

Time necessary for the plasma concentration of a drug to decline by 50% during the elimination phase?

Time necessary to eliminate 50% of the drug from the body?

A

Elimination half time

Elimination half life

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17
Q

Elimination half time:

  • It is directly proportional to its?
  • It is inversely proportional to its?
  • It is independent of the?
A
  • Vd
  • Clearance
  • Dose of drug administered
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18
Q

Elimination half life:

Drug accumulation occurs if ___ are LESS than the ___.

A
  • Dosing intervals

- Elimination half times

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19
Q

Elimination half time and elimination half life are not equal when the decrease in the drug’s plasma concentration does not parallel its ?

A

Elimination from the body

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20
Q

The ___ is the time it takes for 50% of the drug to leave the PLASMA during elimination.
The ___ is the time it takes the BODY to eliminate half of what it was given.

A

Elimination half time

Elimination half life

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21
Q

Systemic absorption - regardless of the route of drug administration, depends on the drug’s ___.

A

-Solubility

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22
Q

Oral administration of medications:
___ = drugs absorbed from the GI system enter the portal venous blood and pass through the liver before entering the systemic circulation for delivery to tissue receptors. Here they are extensively extracted and metabolized.

*PO meds are dosed higher because we lose a lot to the?

A

First Pass Effect

*Portal system

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23
Q

Administration of Medications:

___ = Rapid onset; bypasses the ___and thus prevents the ___

A

Sublingual, transmucosal
-liver
-first pass effect
(does not go through portal system)

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24
Q

Provides sustained therapeutic plasma concentration of drug?

A

Transdermal

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25
Q

Transdermal:

  • Absorption occurs along hair follicles and sweat ducts that function as ?
  • Rate limiting step is diffusion across the ?
  • Thickness and blood flow = factors reflected in the skin’s permeability for drugs
  • This can occur at the site?
A
  • Diffusion shunts
  • Stratum corneum of the epidermis
  • Contact dermatitis
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26
Q

Rectal: (unpredictable responses following rectal administration)

1) Transport to the portal system via superior hemorrhoidal veins?
* Thereby ___.
2) Bypasses portal system?

A

1) Proximal rectum
* First pass effect
2) Distal rectum

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27
Q

Achieve therapeutic plasma levels precisely and rapidly?

A

IV

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28
Q

Most drugs are ___ or ___ present in both ionized & non-ionized forms.

A

Weak acids or bases

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29
Q

Usually lipid soluble and can diffuse across lipid cell membranes such as BBB, renal, tubules, GI, epithelium, hepatocytes)?

*This fraction of drug is therefore pharmacologically ___, undergoes reabsorption across ___, is absorbed from the ___ and is metabolized by the ___.

A

Non-ionized

  • ACTIVE
  • Renal tubules
  • GI tract
  • Liver
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30
Q

Ionized fraction of the drug is poorly ___, can not penetrate ___, and is repelled from portions of the cell with similar changes. They are excreted by the ___, ___!!

A
  • Lipid soluble
  • Lipid cell membranes
  • Kidneys
  • Unchanged!
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31
Q

Drugs that are highly ___ we want to avoid giving to people with kidney problems/failure.

A

Highly ionized

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32
Q

Degree of ionization depends on its ___ and the __ of the ___.

Changes in ___ can result in large degree of ionization.

A
  • dissociation constant (pK)
  • pH of the surrounding fluid
  • pH
33
Q

Changes in pH can result in large degree of ionization:

1) acidic drugs are highly ionized at ___.
2) alkaline drugs are highly ionized at ___.

If giving an acidic drug in an acidic environment you will need to ___ the amount that you are giving. (need to have the lowest therapeutic dose)

A

1) alkaline pH
2) acidic pH
reduce

34
Q

Concentration difference of total drug can develop on 2 sides of a membrane that separates fluids with different pHs.
*Example?

A

Ion Trapping

*Placenta

35
Q

Think of placenta (baby is more acidotic than mom) give weak base, weak base goes to mom who is more alkalotic and then the baby which is more acidotic, thus the drug in the placenta will become more ionized and will then be unable for the drug to cross back over to mom. Will have to wait for the baby aka placenta to metabolize the drug back out. This is an example of?

A

Ion Trapping

36
Q

Plasma Proteins: Most drugs bind to plasma proteins in various degrees
Proteins are:
1) ___ = acids
2) ___ = bases (tends to attach more to bases)
3) ___

A

1) albumin
2) alpha-1 acid glycoprotein
3) lipoproteins

37
Q

Protein binding = only free or unbound fraction of drug is easily or readily available to cross cell membranes.
*___ is therefore inversely proportional to protein binding

*Patient with low ___ levels we want to be cautious when giving highly protein bound drugs

A
  • Vd

* albumin

38
Q

1) Unbound drug in the ___ is metabolized and excreted more readily well
2) Drugs that are highly protein bound (warfarin, propranolol, phenytoin, diazepam) are markedly affected by alterations in ___.

A

1) Plasma

2) Protein binding

39
Q

1) Volume of plasma cleared of drug by metabolism and excretion?
2) Almost all drugs administered in the therapeutic dose ranges are cleared at a rate proportional to the amount of drug present in the plasma?

A

1) Clearance

2) First Order Kinetics

40
Q 
A few drugs will exceed the metabolic or excretory capacity of the body to clear drugs by first order kinetics, even at therapeutic doses. 
In this situation constant amount of drug is cleared per unit of time this is known as? 
Examples include (3)?
A

Zero Order Kinetics

-Aspirin, dilantin, ETOH

41
Q

No matter what body can only handle a certain amount of drug per unit time. Body does not have the enzymes to break down the drug, so the body requires a certain amount of time to eliminate and metabolize the drug. If we keep giving a drug (a first order kinetic drug) because we aren’t getting the effect we want we can overload the system and then we move to?

A

Zero order kinetics

42
Q

Hepatic Clearance = hepatic blood flow and hepatic extraction ratio. If hepatic extraction for a drug is high (greater than ?) than the clearance of the drug will depend on the ___.
*This is termed?

A

0.7
Hepatic blood flow
*Perfusion dependent elimination

43
Q

If hepatic ratio is ? and you have a low BP, you have reduced hepatic blood flow and drug will be cleared more slowly.
-Drug is not being brought to liver fast enough - perfusion dependent if greater than 0.7

*Most of clearance occurs in the?

A

Greater than 0.7

*Liver

44
Q

If the hepatic extraction ratio is low ? a decrease in protein binding or an increase in enzyme activity will increase hepatic clearance.

  • Changes in hepatic blood flow will have ___ changes in its clearance.
  • This is termed?
A

Less than 0.3

  • minimal
  • Capacity dependent elimination
45
Q

Not dependent on liver blood flow more dependent of enzymes?

A

Capacity dependent elimination

46
Q

Most important organ for the elimination of unchanged drugs or their metabolites?

A

Renal clearance

47
Q

___ compounds are excreted more efficiently by the kidneys than ___ drugs.
Highly ___ drugs are reabsorbed such that little or no unchanged drug is excreted in the urine.

A

Water soluble compounds
Lipid soluble drugs
Highly lipid soluble drugs

48
Q

1) ___ drugs excreted by the kidneys unchanged.
2) The most important organ for eliminating unchanged drugs?

*Highly lipid soluble drugs tend to get reabsorbed to go to liver to get broken down for excretion.

A

1) Ionized drugs

2) Kidneys

49
Q

Biotransformation to convert pharmacologically active, lipid soluble drugs into water soluble and often inactive drugs

A

Metabolism

50
Q

1) Increased ___ reduces the Vd for a drug and enhances its renal excretion.
2) ___ is not always synonymous with inactivation or detoxification as some metabolites of certain drugs are active. (Versed is a good example)

A

1) water solubility

2) Metabolism

51
Q

Most common. Constant fraction of available drug is metabolized in a given time period?

A

First Order Kinetics

52
Q

Plasma concentration of drug exceeds the capacity of metabolizing enzymes?
Metabolism of a constant amount of drug per unit of time.
Ex: ETOH, ASA, Dilantin

A

Zero Order Kinetics

53
Q 
Pathways of Metabolism:
1) Phase 1?
2) Phase 2? 
         *Parent or metabolite drug reacts with an endogenous substrate 
          to form \_\_\_.
A

1) Oxidation - Reduction - Hydrolysis

2) Water soluble conjugates (Conjugation)

54
Q

Sites for metabolism? (5)

A
  • Plasma
  • Lungs
  • Kidneys
  • GI tract
  • Liver
55
Q
  • Hepatic microsomal enzymes are responsible for ___ of most drugs.
  • Main site for metabolism is the?
A
  • Metabolism

* Liver

56
Q

1) These are located in Hepatic Smooth ER?
2) ___: is a large number of different protein enzymes involved in oxidation, reduction and conjugation of a large number of drugs.

A

1) Hepatic microsomal enzymes
2) Cytochrome P-450

*Hepatic microsomal enzymes together are known as the Cytochrome P-450

57
Q

*There are 6 well characterized forms, or ___, of the Cytochrome P-450 system involved in drug metabolism in humans.
The nomenclature is as follows: (Ex: CYP2D6)
1) The letters CYP stand for ___
2) The first number denotes ___
3) The second letter describes the ___
4) And finally the second number stands for the specific ___

A
  • Isozymes
    1) Cytochrome P-450
    2) Genetic family
    3) Genetic subfamily
    4) Gene/isozyme
58
Q

1) Drugs and chemicals stimulate activity of these enzymes?
* Ex: Someone with seizure disorder that is on a barbiturate will burn through drugs very quickly, because enzymes are eliminating these drugs much faster. Will need to give your doses closer together.

2) Enzymes are named ?

A

1) Enzyme Induction

2) Genetically

59
Q

These metabolize drugs mostly by conjugation and hydrolysis?

To a lesser degree also by oxidation reduction.

A

Nonmicrosomal enzymes

60
Q

Non-microsomal enzymes:

1) Present in ___ mostly, also present in the plasma, GI tract.
2) Are responsible for hydrolysis of drugs that contain ___ (succhs, emolo).
3) Do not undergo ___.
4) Determined ___.

A

1) Liver
2) Ester bonds
3) Enzyme induction
4) Genetically

61
Q

Pharmacodynamics: (how the drug works in your body)
The most common mechanism by which drugs exert pharmacologic effect is by = Interaction with specific macromolecules in the lipid bi-layer of cell membranes called?

A

Receptors

62
Q 
Concentration of Receptors:
Can increase (up-regulate) or decrease (down-regulate) in number in response to \_\_\_.
A

Specific stimuli

63
Q

State of ___ ___ Theory:

Non-activated receptors are converted to active by the ___.

A

State of Receptor Activation Theory

drug

64
Q

The more receptors occupied by drug the more effect?

A

Receptor Occupancy Theory

65
Q

Non-receptor Drug Action: (Rare)

  • Mechanisms other than receptor-drug interactions - for example:
    1) Chelating drugs form bonds with ___ that may be found in the body.
    2) Antacids neutralize gastric acid by a ___ (prilosec).
A

1) metallic cations

2) direct action

66
Q

Mimic cell signaling molecules by activating the same receptor sites and causing similar effects?

A

Agonist drugs

67
Q

Bind to receptors as well and change the configuration of the agonist site or bind to it, preventing effect from cell signaling molecules?

A

Antagonist drugs

68
Q
  • ***The affinity of a drug for a specific macromolecular component of the cell and its intrinsic activity are intimately related to its ___.
  • The relationship is frequently quite stringent, and relatively minor modifications in the drug molecule, particularly such subtle changes as ___, may result in major changes in ___.
A
  • ***Chemical structure
  • Stereochemistry
  • Pharmacological properties
69
Q

Stereochemistry:
Enantemerism can be produced by sp3 hybridized ___.
___ about the chiral carbon is not possible, 2 stable forms of the molecule can exist.

A

Carbon atoms

Free rotation

70
Q

Stereochemistry:

1) Interaction with biological receptors can differ greatly btw ___, even to the point of no binding.
2) Some ___ may cause side effects or entirely different effects than its mirror image.
3) Some ___ may have little to no effect.

A

1) 2 enantomers
2) Isomers
3) Isomers

71
Q

___ has 2 chiral centers and 4 isomers.

*Easy to manipulate chemical structures to make medication more potent.

A

Ephedrine

72
Q

The ability of a drug to produce the desired therapeutic effect?
(how quickly can you achieve that effect)

A

Efficacy

73
Q

The relationship btw the therapeutic effect of a drug and the dose necessary to achieve that effect?

A

Potency

74
Q

1) Median Effective Dose?

2) Median Lethal Dose?

A

1) ED50

2) LD50

75
Q

This indicates the therapeutic index of a drug for that effect?

A

The ratio of LD50 to ED50

76
Q

ED50 vs LD50:

1) Suggests how selective the drug is in producing its ___.
2) Estimate the ___.

A

1) Desired effects

2) Clinical therapeutic index

77
Q

People in whom unusually low dose of drug produces its expected pharmacologic effect?

A

Hyper-reactive

78
Q

People who are allergic?

A

Hypersensitivity

79
Q

Second drug acting with the first will produce equal to the sum of both?
1 + 1 = 2

A

Additive Effect

80
Q

Two drugs interact to produce an effect greater than their sum?
1 + 1 = 3

A

Synergetic Effect

Pharm Exam 1 - summer (3 decks)

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