Flashcards in Lec 56: Pharmacokinetics II Deck (11):

1

## What are the benefits of administering a constant IV of a drug versus a single oral dose?

###
1. The drug avoids first pass metabolism

2. Drug is more efficiently absorbed into the bloodstream

2

## What are the drawbacks of administering a constant IV of a drug versus a single oral dose?

### It takes longer for the drug to reach effective concentration in the blood

3

## Approximately how long does it take for a drug to reach steady state concentration after the first dose (in half lives)?

### 4-5 half lives

4

## What is the formula for accumulation factor?

### Accumulation factor = 1/fraction lost in one dosing interval

5

## If a drug is given once every half-life, what is the accumulation factor?

### Accumulation factor = 2

6

## What are the three key things the patient must know about the drugs he/she is prescribed?

###
1. How much

2. How often

3. What form

7

## What is the therapeutic range of a drug?

### The concentration of drug that is in between the maximum safe concentration and the minimum effective concentration

8

## When we prescribe medications why do we aim for between 1/2 the therapeutic range and the minimum therapeutic range? Why not use the whole therapeutic range?

### Once the drug concentration goes above half the therapeutic range, side effects are more prevalent

9

## What is the formula for dosing rate? Why is it important?

###
1. Dosing rate = volume of plasma cleared x concentration of drug in that volume

2. Dosing rate determines how much drug you should administer/ time (usually in mg/hr) to maintain steady state concentration

10

## If the half life of drug is <4 hours is periodic dosing or constant infusion more appropriate?

### constant infusion

11