Principles of Drug Action Flashcards

1
Q

Drug dosage, absorption, distribution, metabolism, and elimination refers to:

A) pharmacodynamics

B) pharmacokinetics

A

pharmacokinetics

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2
Q

Concentration of drug at site of action, therapeutic effects, and side effects refer to:

A) pharmacodynamics

B) pharmacokinetics

A

A) pharmacodynamics

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3
Q

Drug indications means getting which of the following?

right drug

right space

right concentration

right period of time

A

right drug

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4
Q

Distribution/mechanism means getting which of the following?

right drug

right space

right concentration

right period of time

A

right space

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5
Q

Mechanism/metabolism means getting which of the following?

right drug

right space

right concentration

right period of time

A

right concentration

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6
Q

Pharmacokinetics means getting which of the following?

right drug

right space

right concentration

right period of time

A

right period of time

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7
Q

Some consequences of poor drug therapy: (5)

A
  • No therapeutic benefit
  • Side effects
  • Poor compliance
  • Drug interactions
  • Drug resistance
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8
Q

Dose-response curve

___-axis represents drug response as % maximal response.

___-axis represents dose amount.

A

y

x

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8
Q

This dose response curve is better to evaluate/compare drug effects over the typical large concentration (or dose) ranges used in pharmacology:

arithmetic scale or semi-logarithmic scale?

A

semi-logarithmic

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8
Q

EC50 is the effective ______ to produce 50% of maximal response–a measure of potency.

A

concentration

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9
Q

Since we often do not know the concentration of free drug in the body, we can use the effective ____ of drug producing 50% of maximal response, known as ____ to compare the potencies of 2 or more drugs.

A

DOSE

ED50

Note: The units of ED50 is in units of DOSE!

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10
Q

Potency refers to the _______ necessary to achieve the desired effect.

A

dose

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11
Q

Definitions:

  • IC50
  • TD50
  • LD50
A
  • inhibitory concentration
  • toxic dose
  • lethal dose
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12
Q

The level of effect a drug elicits is _____.

A

efficacy

Efficacy is synonymous with response

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13
Q

The amount or concentration of drug responsible for a response is _____.

A

potency

Potency is synonymous with dose.

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14
Q

What is the rank order of efficacy of the 3 drugs?

A

bumetanide and furosemide are more efficacious than metolzaone

15
Q

What is the rank order of potency for the 3 drugs?

A

metolazone and bumetanide are equally more potent than furosemide

Measure of equal ED50 or EC50 of drugs.

Don’t care about maximal effect!

16
Q

Which drug is more potent, morphine or aspirin? Why?

Which drug is more effective? Why?

A

Morphine is more potent because ED50 falls at a much lower dose than aspirin.

Morphine is more effective because the response curve is much greater than aspirin.

Caution on exam: Which is better? Depends!

17
Q

Most side effects of drugs are ______ based.

A

mechanism

18
Q

ON EXAM:

Most side effects are mechanism based due to: (4)

A
  • therapeutic mechanism of action
  • off-target mechanism of action
  • interaction/interference with other drugs
  • Often, but not always, dose-dependent
19
Q

_______ Index quantifies side-effects to evaluate drug safety.

A

Therapeutic

20
Q

Therapeutic index = ____/_____

or _____/_____.

The larger the ratio, the safer the drug.

A

TD50/ED50

LD50/ED50

21
Q

Therapeutic index can be any _____ drug effect, and the denominator can be any ______ outcome.

A

adverse

therapeutic

22
Q

Drugs can act directly or indirectly on: (4)

A
  • receptors
  • channels
  • transporters
  • enzymes
23
Q

Mechanisms of drug action: (6)

A
  • Act competitively or irreversibly
  • Mimic or antagonize endogenous substances
    • Classic: e.g, drugs affecting autonomic nervous system
    • Emerging: Biologics
  • Drugs and drug target can be pleiotropic (affect many systems) or very specific
  • Can impair key point(s) in a metabolic chain to collapse the whole
  • Toxicity is usually mechanism-based and is rarely idiosyncratic
  • Metabolism both creates (pro-drugs) and destroys
24
Q

Some drugs work by unconventional mechanisms of action: (6)

A
  • disrupters of structural proteins
  • enzyme drugs (thrombolytics)
  • covalently link to macromolecules
  • chemically react with small molecules (antacids)
  • others (vaccines, vitamins, osmotics)
  • drugs that bind free molecules or atoms
27
Q

What drug is used to treat HIV-1 infection?

  • Name:
  • Pharacodynamics:
  • Pharmacokinetics:
  • Other:
A
  • Name: Emtriva, or emtricitabine
  • Pharacodynamics:cytosine analog reverse transcriptase inhibitor
  • Pharmacokinetics:high bioavailability, once daily, low protein binding (means low drug interaction)
  • Other: Activity against HBV