Dosing Regimens Flashcards

1
Q

What is the goal of dosing regimens?

A

to achieve and/or maintain a therapeutic concentration while avoiding toxicity

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2
Q

What are different type of dosing regimens?

A
  • single dose (bolus)
  • continuous infusion
  • intermittent dosing (fixed-dose/fixed time)
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3
Q

Toxicity can be manifested as what?

A

side effects

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4
Q

What does this describe:
- plasma levels increase as drug distributes until the peak is reached
- levels fall due to metabolism and elimination

A

single dose

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5
Q

When you give an IV, when will you see the max peak of concentration?

A

right after you administer the drug

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6
Q

In a single oral dose, what happens?

A
  • you take it once
  • after period of time, it reaches its peak
  • tapers off over time
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7
Q

In a single IV dose, what happens?

A
  • max concentration occurs at time it is given
  • tapers off over time
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8
Q

What is the goal of intermittent dosing?

A

to achieve a steady-state concentration

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9
Q

How can intermittent doses be given?

A

oral or IV

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10
Q

How many half-lives does it take to achieve steady-state?

A

5 half lives
(90% steady-state is 3.3 half-lives)

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11
Q

Where might you see side effects/toxic effects of an intermittent dose?

A

at the peaks

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12
Q

What is the lowest point on concentration before the next dose in an intermittent dose?

A

trough

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13
Q

What is an example of intermittent doses?

A

blood pressure medication - given continuously, patient reaches a steady-state if they are taking it correctly

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14
Q

If we cannot wait 5 half-lives to reach a steady-state, what can we give patients?

A

loading dose

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15
Q

What is the goal of loading dose?

A

to achieve a target blood level quickly

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16
Q

What types of drugs are beneficial to use loading dose?

A
  • long half-life drugs
  • immediate effect is needed
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17
Q

What describes when a large initial dose followed by maintenance doses to maintain therapeutic blood levels?

A

loading dose

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18
Q

Does loading dose get a patient to steady-state?

A

no, it isn’t taken continuously

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19
Q

What is not effective if plasma concentration is independent of efficacy?

A

loading dose

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20
Q

When will you reach a steady-state?

A

after 3.3 half-lives

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21
Q

why is there more potential for side effects if intermittent dosing is every 24 hours?

A

dose is higher

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22
Q

Can you increase the rate of a continuous IV infusion to get to steady-state faster?

A

no, its always after 3.3 half lives

23
Q

If there is a longer timeframe between doses of a drug, what happens?

A

higher dose is given

24
Q

Increasing rate of drug will increase what?

A

concentration of the steady state, but WILL NOT effect time to get to steady-state

25
Q

We expect to see the effect of the drug in who?

A

most people most of the time
“most people” = young, middle aged adults

26
Q

Drugs are rarely studied in who?

A

children and elderly

27
Q

What should be made with respect to the results seen in the individual regardless of what is seen in the population?

A

clinical monitoring and adjustments

28
Q

What is a standard curve showing how concentration changes over time after oral administration of a drug?

A

concentration vs time curve

29
Q

What is AUC?

A

area under the curve

30
Q

What measures the total exposure to drug after a dose?

A

area under the curve

31
Q

Drugs/total drug exposure can be what % off under the curve?

A

20%

32
Q

What is Cmax?

A

maximum concentration of drug/peak effect of drug you will get

33
Q

What is MEC?

A

minimum effective concentration (concentration needed to see a minimum effect)

34
Q

What is tmax?

A

time it takes to reach maximum concentration

35
Q

What is the lag period?

A

period of time after administration where it is not working

36
Q

What can be the same for IV, oral, and extended release drugs?

A

area under the curve

37
Q

What is used to demonstrate the expected response to a given dose of a drug?

A

dose-response curve

38
Q

What includes the range of concentrations needed to demonstrate a relationship is so great a semi-log plot is used rather than the linear format?

A

dose-response curve

39
Q

Linear formatted dose-response curves are hard to determine what?

A

different concentrated, so log plots are used to get a better range of concentration

40
Q

What is the dose required to produce a response?

A

potency

41
Q

What does potency of a drug depend on?

A

its affinity

42
Q

What describes the strength of binding between a receptor and its substrate (how much does the drug like the receptor)?

A

affinity

43
Q

What is measured by Kd (equilibrium dissociated constant)?

A

affinity

44
Q

What does a high Kd value mean?

A

low affinity, so strength of binding between receptor and substrate is decreased, so potency is decreased (will take longer to reach desired efficacy)

45
Q

What does a low Kd value mean?

A

high affinity, so strength of binding between receptor and substrate is increased, there will be a stronger response, and potency will increase

46
Q

Two drugs do the same thing, but one requires 5 mg to be effective (drug A), and the other requires 20 mg to reach same effectiveness (drug B), which is more potent?

A

Drug A

47
Q

What is EC50?

A

concentration of drug that produces half the maximal effect

48
Q

What is used to identify the relative potency of a drug?

A

EC50

49
Q

What is helpful in comparing potencies of drugs that are designed to produce the same effect?

A

EC50

50
Q

How is EC50 determined?

A

in a test tube (in-vitro comparison)

51
Q

What is described as the maximum effect a drug is capable of producing (how much of an effect after drug binding)?

A

efficacy

52
Q

What is described as the degree to which a response is achieved?

A

activity

53
Q

What is Emax?

A

maximal effect of drug