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SRNA4TopicsAnesthesia > EXAM 2 Reading 2 (B. Ch11) > Flashcards

EXAM 2 Reading 2 (B. Ch11) Flashcards

1
Q

What term refers to the dose of a drug required to produce a given effect in 50 percent of subjects?

A

Potency

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2
Q

Select two Phase I reactions associated with drug metabolism.

A

Hydrolysis

Reduction

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3
Q

Select two inducers of hepatic drug metabolism.

A

Rifampin

Phenytoin

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4
Q

Which is the single most important enzyme, accounting for 40-45 percent of all mediated drug metabolism?

A

CYP3A4

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5
Q

Which drug exhibits the classic drug-drug interaction associated with serotonin syndrome when combined with MAOIs?

A

Meperidine.

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6
Q

Which route of administration exhibits absolute drug bioavailability?

A

IV

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7
Q

Most intravenous drugs exhibit absolute bioavailability. The exception are drugs such as ____Why?

A

fentanyl which undergo absorption into the pulmonary endothelium.

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8
Q

Which term refers to the theoretical volume of blood from which a drug is completely and irreversibly removed in a unit of time?

A

Elimination clearance.

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9
Q

Most cellular drug receptors are located

A

Within the cell membrane

few in the cytoplasm of nucleoplasm

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10
Q

Dose-response curves provide information about all of the following aspects of pharmacologic effects except:

A

The steady-state plasma concentration (CPss50)

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11
Q

The slope of a dose-response curve demonstrates

A

the rate of increasing effect with an increased dose.

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12
Q

The dose-response curve also demonstrates the

A

efficacy, or maximal effect of a drug as well as the potency (ED50)

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13
Q

A dose-response curve can also demonstrate variability in

A

drug effect if it measures multiple subjects.

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14
Q

The steady-state plasma concentration (CPss50) is determined by a

A

concentration-response curve using a continuous infusion of a drug

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15
Q

What pharmacodynamic value of a drug can be determined by a concentration-response curve when administering a continuous infusion of a drug?

A

CPss50 The steady-state plasma concentration (CPss50) is determined by a concentration-response curve using a continuous infusion of a drug.

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16
Q

Which Phase 1 reaction is characterized by reactions that remove electrons from a molecule?

A

Oxidation

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17
Q

The excretion of an acidic drug will be faster if

A

Alkaline

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18
Q

Weak acids are excreted more efficiently if the urine and

A

is alkaline

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19
Q

Weak bases are excreted more efficiently if the urine is

A

Acidic

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20
Q

Weak bases excreted more efficiently if the urine is acidic. An example is

A

An example would be the use of sodium bicarbonate in cases of aspirin poisoning. Aspirin, or salicylic acid, is obviously an acid. Because acids are excreted more efficiently if the urine is alkaline, the administration of intravenous sodium bicarbonate will alkalinize the urine and increase the rate at which the kidneys eliminate it

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21
Q

With regards to drug-receptor complexes, what is desensitization?

A

The binding of an agonist to the receptor produces a decreased response

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22
Q

When receptors are exposed to an agonist more than normal, they becomes

A

desensitized. This means that the binding of the agonist to the receptor exerts a lower-intensity response than normal.

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23
Q

The dose-response curve produced by the binding of an opioid to an opioid receptor represents the drug’s

A

efficacy

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24
Q

The dose-response curve produced by the binding of the opioid to an opioid receptor describes the drug’s

A

efficacy

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25
Q

It is a measure of the effect the drug produces.

A

Efficacy

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26
Q

is the ability of a drug to bind with a receptor to form a stable complex.

A

Affinity

27
Q

Potency refers to the relative dose of a drug that is required to produce the

A

effect and is closely associated with the affinity of the drug for the receptor

28
Q

After three half-lives, what percentage of an administered drug remains?

A

12.5%

29
Q

The two-compartment pharmacokinetic model is most useful for explaining the characteristics of

A

Lipid soluble agents.

30
Q

Where are most drug receptors located?

A

The cell membrane

31
Q

Which of the following is a Phase II reaction?

A

Conjugation

32
Q

Which of the following terms refers to compounds that bind to receptors without producing any changes in cellular function?

A

Antagonist

33
Q

Which drug or drug class is an inhibitor of hepatic drug metabolism?

A

SSRIs

34
Q

What is the term that describes the extent to which a drug reaches its effect site after its introduction into the circulatory system?

A

Bioavailability

35
Q

Select two common treatments for moderate to severe serotonin syndrome.

A

Oral cyproheptadine is the most common treatment of serotonin syndrome but chlorpromazine has also been used in combination with supportive care

36
Q

The gamma-amino butyric acid receptor is an example of

A

a ligand-gated ionophore

37
Q

The two major ways in which a drug can bind to a receptor and cause a change in cellular function are The GABA receptor is a ligand-gated ionophore.

A

ionophores (ion channels) and G-proteins.

38
Q

The binding of drugs or neurotransmitters to a GABA receptor opens a

A

chloride channel, allowing the influx of chloride into the cell.

39
Q

What are the 2 non IV routes for which tissue perfusion does not affect drug onset of effect because the drug is delivered adjacent to the site of action.

A

The intrathecal space

Epidural space.

40
Q

Is rarely the side at which drug produces their action

A

Blood

41
Q

Absorbed faster: lipophyillic or hydrophyllic

A

lipophyllic because diffusion across lipid cellular barriers is faster.

42
Q

Those 2 organs equillibrate fast

A

Brain and kidneys

43
Q

Explain the redistribution

A

Redistribution of opioid from the highly perfused but low tissue volume brain back in the plasma will eventually decrease the concentration of drug at its site of action below the therapeutic threshold and thereby halt its effect.

44
Q

What is the major determinant of the limited bioavailability of many drugs administered via the gastrointestinal tract?

A

This first-pass metabolism by the liver

45
Q

IV methods administration is that the same impediments to rapid systemic absorption can provide

A

a prolonged drug effect

46
Q

Drug transport, either into or from the tissue, is usually not saturable, so drug uptake by the tissue is mostly limited by)

A

the blood flow to the tissue (flow-limited drug uptake

47
Q

What 2 things determine the rate of drug equilibration with the plasma in each tissue bed

A

The distribution of cardiac output to the different tissue beds and the cellular mass of the tissue

48
Q

In contrast, the well-perfused muscle and splanchnic tissues take hours to approach equilibrium why?

A

due to their large tissue volumes relative to blood flow

49
Q

When the concentration of drug in the tissue becomes higher than the plasma concentration, the overall movement of drug is

A

from the tissue to the plasma

50
Q

This redistribution of an opioid or hypnotic from the highly perfused but low tissue volume brain back into the plasma will eventually

A

decrease the concentration of drug at its site of action below the therapeutic threshold and thereby halt its effect.

51
Q

It is important to note that the brain may redistribute drug minutes after a bolus of drug has been administered. But tissue beds such as the muscle, which are slower to equilibrate because of the large capacity for drug uptake ,

A

will continue to take up drug until the plasma concentration decreases below the tissue concentration as drug is metabolized, excreted, and drug distributed throughout the bod

52
Q

With repeated injections or an infusion of drug,

A

tissue uptake of drug will continue as long as the blood–drug concentration remains above that of tissue–drug concentration.

53
Q

Thus, when drug administration is stopped or the rate is decreased, these tissues begin to act like

A

depots, causing net transfer of drug to blood and slowing the rate of further decrease of the plasma concentrations (Fig. 7-2).

54
Q

When the rate of net tissue transfer of drug to blood is equal to the elimination rate of drug from the body, then the blood

A

drug concentration versus time profile enters into the terminal elimination phase where the rate of change (or half-life) remains constant (3).

55
Q

most common cause of interindividual variability in the rate of drug elimination from the body.

A

Genetic polymorphisms of the enzymes involved in drug metabolism

56
Q

The cytochrome P450 (CYP P450) superfamily of enzymes, which are found in the

A

endoplasmic reticulum of hepatocytes and some other cells,

57
Q

Some drugs, such as____and ____ can be directly conjugated to glucuronide without phase I reactions.

A

propofol and morphine

58
Q

Vd In a purely physical sense, the

A

amount (mass) of solute divided by a known physical volume of fluid will equal the concentration of the solute in the fluid.

59
Q

Usually, drugs that have clearances near that of liver blood flow are very efficiently biotransformed by phase I reactions (e.g., fentanyl) or phase II reactions (e.g., propofol) in the liver and, in the case of propofol, also in the kidneys. With such drugs, the elimination clearance

A

is considered to be flow limited, meaning the clearance will only decrease if blood flow to the organ decreases (e.g., with low cardiac output).

60
Q

For other drugs that are less efficiently biotransformed (e.g., midazolam), the clearance is more (or even solely)

A

influenced by the enzymatic rate.

61
Q

Limit the fraction of drug eliminated from the blood flowing to the organ. In these cases, blood flow is less of a factor in determining elimination clearance, and these drugs’ clearance are referred to as

A

capacity limited.

62
Q

Most drugs are eliminated as a fixed fraction per unit of time. This circumstance is known as

A

first-order kinetics and the fraction eliminated is the rate constant (units of time−1), and drug concentration decreases exponentially

63
Q

have more significant clinical effects on pharmacokinetic parameters than all but the most extreme derangements of the hepatic or renal function.

A

Weight and age

64
Q

T 1/2 combines

A

Vd and elimination clearance.

T 1/2 = 0.693 x Vd/Cle

SRNA4TopicsAnesthesia (47 decks)

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