4 drug absorption caldwell

Question 1

Describe C_T or C_SS

Answer 1

C_T: target concentration in plasma. Desired concentration the physician wants to produce therapeutic effect.

C_SS: steady state concentration. Drug in equals drug out.

Question 2

Describe bioavailability relative to IV concentration.

Answer 2

F = bioavailability, by IV F = 1 all other routes will be measured against the original route (usually IV) to the new route as a ratio

Question 3

Describe the First Pass Effect and apply it to a clinically-relevant case scenario.

Answer 3

Routes that use the length of the GI tract requires metabolism by the liver which will decrease bioavailability significantly

Question 4

Apply a calculation of an equivalent dose of a medication given at various F values to a clinically-relevant case scenario.

Answer 4

dose(new) = F(old route)*dose(old) / F(new route)

Question 5

Give 3 limitations of oral drug administration.

Answer 5

first pass effect

GI absorbance factor

pts ability to ingest a drug orally

Question 6

Give advantages of buccal, sub-lingual and rectal drug delivery versus oral. Apply two disadvantages of rectal administration to a clinically-relevant case scenario.

Answer 6

all except rectal bypass first pass effect

rectal will have half dose bypass and half dose affected by first pass effect

Question 7

Apply three advantages of IV drug administration and to a clinically-relevant case scenario.

Answer 7

complete amount directly available

no mechanism to reduce the initial concentration given (absorption mechanism)

ability to calculate and titrate exact amounts at a constant rate

Question 8

Give one advantage and one example of topical drug administration.

Answer 8

can be used to treat over a very extended period of time

ie. nicotine patches

Question 9

Apply three advantages of inhaled drug administration to a clinically-relevant case scenario.

Answer 9

direct route to target if pulmonary

immediate action

quick elimination