Drug Distribution

Question 1

therapeutic window

Answer 1

-the range of drug concentrations in the blood which produce a therapeutic affect without unacceptable toxicity

Question 2

agonist

Answer 2

• a ligand that binds to receptor

- alters the proportion of them in an active state and thereby elicits a biological response

Question 3

receptor

Answer 3

-a collection of molecules in the body which bind agonists and elicit a response through signaling

Question 4

EC50

Answer 4

• the molar concentration of an agonist that produces 50% of the maximal possible effect of that agonist
• the action of the agonist may be stimulatory or inhibitory

Question 5

ED50

Answer 5

• the dose of a drug that produces, on average, a specified all or non response in 50% OF THE TEST POPULATION
• OR if the resopnse is graded, the dose that produces 50% of the maximal effect of that drug

Question 6

efficacy

Answer 6

the degree to which different agonists produce varying responses even when occupying the same portion of the receptor
-this have everything to do with the outcome/response when given the drug

Question 7

affinity

Answer 7

• a measure of how well a drug binds to a receptor
• has nothing to do with how well the drug works in eliciting a response
• the lower the EC50 or ED50, the higher the affinity

Question 8

partial agonist

Answer 8

• has a lower efficacy than a full agonist
• this is independent of the affinity
• in the presence of a full agonist, a partial agonist could behave like a full agonist

Question 9

antagonist

Answer 9

• a drug that reduces the action of an agonist, often by acting at the site
• competitive (no change in Emax) and noncompetitive (change in Emax)

Question 10

LD50

Answer 10

a dose of a drug that produces death in 50% of the test animals

Question 11

therapeutic index

Answer 11

• ratio of LD50/ED50
• this ratio is a relative indication of safety
• you want this number to be as large as possible
• even if it is high, the high dose of efficacy could still oerlap with the LD50, which would make it unsafe at the upper limit of efficacy

Question 12

when are weak acids ionized and unionized

Answer 12

• unionized when pH is below pKa

- ionized when pH is above pKa

Question 13

when are weak bases ionized and unionized

Answer 13

• unionized when pH is above pKA

- ionized when pH is below pKA

Question 14

how to determine the ratio of a drug between two compartments of the body based on the pKa of that drug and the pH of the compartments

Answer 14

(1 + 10^pKa-pH)/(1 + 10^pKa-pH)

-pH in the compartment of interest is in the numerator

Question 15

ionized and unionzied drugs in the kidney

Answer 15

-ionized are excreted and unionized are resorbed

Question 16

acidifying the urine favors the excretion of

Answer 16

-basic drugs becasue they are ionized

Question 17

making the urine more alkaline favors the excretion of

Answer 17

-acidic drugs because they are ionized