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Gastrointestinal > Advanced Pharmacokinetics > Flashcards

Flashcards in Advanced Pharmacokinetics Deck (18):
1

In rapid IV administration how does the drug distribute?

rapidly

2

In rapid IV administration how does the amount of drug in the body fall?

exponentially with time

3

In rapid IV administration what is peak concentration related to?

dose

4

In a short term IV infusion at what rate to drugs infuse?

constant rate

5

Is the peak concentration higher in a rapid IV administration or a short term IV infusion?

rapid IV administration - because in short term IV infusion there will be drug elimination while there is absorption

6

How is the drug eliminated in a short term IV infusion after the infusion is over?

first order - exponentially with time

7

Which type of drugs is a short term IV infusion useful for?

drugs with a small therapeutic window

8

What is the main feature of a long term IV infusion?

at steady state the rate of infusion equals the rate of elimination

9

What is the relationship between steady state concentration and rate of infusion?

proportional - if double the rate of infusion then double the steady state concentration

10

In multiple dosing what is the result of giving the drug every half life?

two-fold variation in plasma concentration

11

In long term IV infusion how long does it take to reach steady state?

7 half lives

12

What is a loading dose?

An initial dose that is higher than the infusion amount so that steady state is reached earlier

13

What is first pass hepatic metabolism?

all drugs that are given orally go first to the liver where they will undergo metabolism before reaching systemic circulation

14

Why is the peak concentration of oral administration not as high as IV administration?

because there is elimination during absorption, because not all of the drug will be absorbed and because some of the drug will undergo first pass hepatic metabolism

15

What is bioavailability?

the proportion of active drug which enters the systemic circulation

16

What is bioavailability for IV administration?

100%

17

What affects bioavailabilty?

how much drug is absorbed and how much drug undergoes metabolism

18

How do you calculate bioavailability?

area under the curve of the method administration/ area under the curve of IV administration