Pharmacokinetics Flashcards

(32 cards)

1
Q

Define pharmacokinetics.

A

the absorption, distribution, and fate of a drug in the body.

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2
Q

What affects the magnitude of a pharmacological effect of a drug?

A

Its concentration at the site of action

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3
Q

At what level in systemic circulation are drugs distributed?

A

capillary level

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4
Q

What are various ways we can measure drug concentration in the body?

A

blood/plasma
urine
saliva

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5
Q

What factors affect the rate at which drugs enter and exit circulation?

A
  • how a drug is delivered
  • physiochemical properties of barriers
  • chemical properties of drugs and cellular environment
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6
Q

What are the more common routes of drug administration?

A

oral

IV/infusion

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7
Q

What are the typical characteristics of drugs that are given via IV?

A

usually protein drugs that are failed to be taken up via oral ingestion

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8
Q

What are disadvantages of IV route of administration?

A

risk of infection

more severe allergic reactions

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9
Q

What are disadvantages oral route of administration?

A

multiple barriers to pass through between the intestine and colon

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10
Q

What are advantages of pulmonary route of administration?

A

fast, quantitative uptake

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11
Q

What affects absorption of a drug?

A
food
dosage
pH
blood flow
other drugs
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12
Q

How does blood flow affect drug absorption?

A

organs with high blood flow: drugs do not stay around long; but there is a constant flow of the drug to that area

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13
Q

What barriers do drugs pass through when given orally?

A

start in lumen of intestines
enter cell membrane of endothelial cells of villi
enter capillary endothelial cell membrane and enter bloodstream

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14
Q

Define bioavailability.

A

rate and extent to which a drug is absorbed and becomes available at the site of action (the proportion of drug administered that reaches systemic circulation)

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15
Q

What affects bioavailability?

A

first pass effect, barriers, solubility/chemistry, distribution to other tissue

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16
Q

Are all oral drugs absorbed?

A

No, drugs that need to treat an intestinal condition may not need to be absorbed to act on their target.

17
Q

What antibiotic is used to treat intestinal infections?

18
Q

What is the order from most accessible to least accessible of drug targets outside of circulation?

A

outside of circulation,
within cells,
within the central nervous system

19
Q

What are different types of barriers drugs may have to pass through?

A

endothelial barrier
intestinal epithelial barrier
alveolar-endothelial barrier
blood brain barrier

20
Q

What are various ways for a drug to get past a barrier?

A
  • go around it

* go through it

21
Q

How do drugs get around a barrier?

A

they pass between the endothelial cells through fenestrae

22
Q

How do drugs go through the cell membrane/barriers?

A

passive diffusion
facilitated diffusion
active transport

23
Q

What is the P-gp transporter?

A

an efflux transporter; cancers can develop this and thus don’t respond to drug therapy

24
Q

What type of superfamily is the Pgp transporter considered?

A

ABC (ATP binding)

* these transport in and out of the cell

25
What is an SLC transporter?
solute transporter transports out of cell usually drug targets
26
Describe the characteristics of molecules that freely diffuse through cell membranes.
low molecular weight high lipid solubility uncharged (nonpolar?)
27
How do you fine partition coefficient? (oil/water equilibrium)
[X1]/[X2]
28
How can you improve membrane permeability of drugs?
remove polar functional groups
29
What molecules more readily cross the cell membrane, polar or nonpolar?
nonpolar
30
What is the purpose of a prodrug?
it masks polar/ionizable groups on a molecule with hydrophobic residues so they are more permeable to the cell membrane
31
Do resorption esters improve or inhibit diffusion of drugs across membranes?
improve
32
What happens to a prodrug after it has crossed the membrane?
they hydrophobic group undergoes enzymatic cleavage.