BPP V

Question 1

What four things does pharmacokinetics help determine? How can we define a compartment?

Answer 1

How often to dose a drug, what size dose to give, how long to expect a dose to last, when to re-dose a drug to sustain the effect;
fluid space containing the drug

Question 2

In a time vs. log Cp plot, what is the alpha phase made up of, and the beta phase?

Answer 2

distribution; elimination (biotransformation or excretion)

Question 3

How is Ke determined? Define Vd, Ct, ka, ke

Answer 3

By rate-limiting step in clearance (metabolic or renal); volume of distribution in kinetic compartment, concentration in compartment after time t, absorption rate constant, elimination rate constant

Question 4

For the single dose response curve (time vs. blood drug concentration), what do A, B, C, and D correspond to regarding compartments?

Answer 4

See notes, 1-61 to 1-62

Question 5

For absorption kinetics, zero order processes are ______ to drug concentration, first order processes are ______ to drug concentration; what equation corresponds to zero order rate?

Answer 5

not sensitive; sensitive; Ct = ka x t, with Ct = concentration of a drug in volume of distribution

Question 6

What about first order rate absorption and its equation? In first order absorption, how do dose and concentration correlate? Bottom line: what do zero order and first order rates signify?

Answer 6

Ct = M/Vd (1-e^-ka x t); amount per unit time vs. proportion per unit time; larger the dose, faster the concentration rises in the compartment

Question 7

A ______ determines the rate of elimination; what equation describes zero order elimination? How would you describe the slope of the graph describing ZOE?

Answer 7

rate-limiting step; Ct = C0 - ke x t;

Linear

Question 8

What is an example of a drug that undergoes zero order elimination that he mentions in class?

Answer 8

Phenytoin

Question 9

For first order elimination, what is the equation? If you see a linear slope regarding first order rate of elimination, what does that imply? Half-life is only associated with what type of process?

Answer 9

log Ct = log Co - (ke x t)/2.303;

The graph was done on log paper (otherwise, you would have a curved line); first order processes!!

Question 10

How do clearance, volume of distribution, and ke relate? What is the equation for half-life? Reorganize and substitute equations. What can increase t1/2 (two things)?

Answer 10

Clearance = Vd x ke; t1/2 = .693/ke; t1/2 = .693 x Vd/Cl;

decrease in clearance from renal or hepatic failure