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Flashcards in Introduction Deck (30)
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1
Q

Describe the 2 phases in the plasma concentration curve

A

Distribution-immediately after administration of the drug

-drug moves from central to peripheral compartments

Elimination phase-more gradual as drug is removed from circulation

2
Q

how does the degree of protein binding relate to volume of distribution?

A

Inversely proportional

Drugs bound to proteins have low volume of distribution

3
Q

Which drugs bind to albumin?

A

Acidic

4
Q

Which drugs tend to bind to alpha-1-acid glycoproteins?

A

basic drugs–local

5
Q

How does binding to protein affect ability to cross cell membrane and elimination

A

Only unbound drug may cross cell membrane.

Free drug will be more available for elimination

6
Q

Are protein bound drugs inert?

A

No,law of mass action shows that since reactions are occuring, protein bound drugs will be released as free drug is metabolized to keep equilibrium

7
Q

What are the two factors that determine the ionization of a drug?

A

pKa of substrate

pH of surrounding fluid

8
Q

If a drug has a pKa of 4.4 and is placed into a solution with a pH of 4.4 how does it ionize?

A

50% ionized, 50% non-ionized

9
Q

What is ion trapping?

A

Occurs when a membrane separates 2 areas of differing pHs (stomach, renal tubules, placenta)

Nonionized portion of the drug will diffuse and equilibrate, but the ionized form cannot

Thus a large concentration differrence exist between the membrane

10
Q

What is clearance?

A

Removal of drug from plasma

11
Q

What is metabolism

A

enzymatic alteration of a drug’s chemical structure

12
Q

WHat are the 4 major types of metabolic reactions for drugs?

A

oxidation

reduction

conjugation

hydrolysis

13
Q

What is the difference between pharmacodynamics and pharmacokinetics?

A

Pharmacodynamics–what the drug does to the body

This included intrinsic sensitivity/responsiveness of the body’s receptors to a drug

Pharmacokinetics–what the body does to the drug

This includes absorption, distribution, metabolism, and excretion of drugs

14
Q

What are enantiomers?

A

2 molecules having the same chemical composition but different orientations around a central atom–mirror images

15
Q

What is the term used to describe a mixture containing both enanitiomers in equal proportions?

A

Racemic

16
Q

What is the difference in a agonist and antagonist

A

Agonist–a drug that produces its clinical effect by binding to a receptor and activating it (mimetic)

Antogonist–a drug that produces its clinical effect by binding to a receptor WITHOUT activating it and simultaneously provents an agonist from stimulating it (blocking)

17
Q

A(n) ___________-acting receptor agonist combines directly with its receptor to trigger its physiologic response, while a ___________-acting receptor agonistproduces its physiologic response by increasing the concentration of ENDOGENOUS substrate at receptor site

A

direct

indirect

18
Q

What is the difference between competitive and noncompetitive antagonism?

A

In competitive antagonism the receptor inhibition can be overcome by increasing the concentration of the agonist at the receptor

In noncompetitive antagonism inhibition CANNOT be overcome by increasing the concentration of the agonist

19
Q

A small dose gives an exaggerated effect

A

hyperactive

20
Q

An allergic reaction

A

hypersensitive

21
Q

Situation where an exceptionally large dose is required to produced the desired/expected pharamcologic effect

A

hypo reactive

22
Q

tolerance develops within a few doses of a drug. Having to increase the dose to get the same effect

A

tachyphylaxis

23
Q

the effect of two chemicals taken together is greater than the sum of their separate effect

A

Synergistic effect

24
Q

the effect of two chemicals taken together is less than the separate effect of either alone

A

antagonistic effect

25
Q

the effect of two chemicals taken together is equal to the sum of their separate effects

A

Additive effect

26
Q

What is a prodrug

A

A biologically inactive compound that can be metabolized in the body to produce a drug

27
Q

Of the 3 routes of enteral administration, which is subject to first pass effect

A

The three routes are oral, rectal and sublinqual. Oral subject to first pass

28
Q

What is the central compartment and at what speed does it uptake drug

A

Rapid uptake

Includes IV fluid, and highly vascularized tissues such as heart, brain, kidneys and liver.

Drugs will equilibrate between compartments and eventually be eliminated from the central compartment

29
Q

what is the peripheral compartment? how quickly does it take up drug?

A

Slow uptake

Includes les vasuclar tissus like fat, bone, and inactive skeletal muscle

30
Q

What is the volume of distribution?

A

Total approximation of all the compartments to which a drug goes.

Relates the amount of drug in the body to the concentration of drug in the blood or plasma