Intro to PK

Question 1

what is pharmacokinetics?

Answer 1

the study of what the body does to a drug - relates how the dose delivered affects the concentration within the body

Question 2

what is pharmacodynamics?

Answer 2

the study of what a drug does to the body - determines how the effect varies with concentration achieved

Question 3

what kind of drug can deliver the drugs intended effects…

free drug or a bound drug?

Answer 3

free drug

Question 4

what is absorption defined by?

Answer 4

a rate constant

Question 5

what is the definition of absorption?

Answer 5

how the drug gets from the dosage form to the site of action

Question 6

what happens when the drug goes to the gut/liver?

Answer 6

becomes metabolised and excreted without exerting its effects

Question 7

what is the definition of distribution?

Answer 7

how the drug moves about the body, and how this movement may affect the concentration

Question 8

what is the definition of volume of distribution ?

Answer 8

This is the apparent volume into which the drug is distributed, depending on the drug properties this value can vary

Question 9

what is plasma/tissue binding?

Answer 9

Drugs can bind to plasma proteins and tissues within the blood stream – drugs are transported partly in solution as free (unbound) drug and partly reversibly bound to blood components

Question 10

what is the definition of metabolism?

Answer 10

how the drug is altered once in the body

Question 11

what are the two types of metabolisms? what’s the significance and what are some examples?

Answer 11

phase 1
- drugs are made more hydrophilic
e.g. reduction, oxidation, hydrolysis

phase 2
- drugs are conjugated to allow for easy excretion
e.g. drug conjugation

Question 12

what’s the definition of clearance? and units?

Answer 12

The volume of plasma/blood that is cleared of drug per unit time – this is an important parameter in pharmacokinetic calculations. Units = L/h

Question 13

what’s the definition of half life? and units?

Answer 13

The time taken for the concentration of the drug in the blood to fall to half its original value. Units = h

Question 14

what’s the definitions of bio equivalence?

Answer 14

showing equivalent bioavailability profiles

Question 15

what are pharmaceutical equivalents?

Answer 15

contain the same active ingredient(s)
same dosage form and the same route of administration identical in strength or concentration

Question 16

what are pharmaceutical alternatives?

Answer 16

contain the same therapeutic moiety but…
salts or complexes of that moiety
dosage forms
strengths

Question 17

why are pharmacokinetics important?

Answer 17

To calculate a maintenance dose for a patient requires a knowledge of both the extent and rate of clearance of the drug.

Question 18

what kinetics do majority of drugs follow for elimination?

Answer 18

95% follow first order
and a small amount follow zero which the elimination process is saturated