Applied Pharmacokinetics: Distribution Of Drugs

Question 1

Define distribution of drugs

Answer 1

It’s the reversible transfer of a drufrom one location to another within the body.

Question 2

How is distribution measured

Answer 2

Plasma or whole blood concentration levels since tissue concentration cannot be measured

Question 3

What factors limit drug distribution

Answer 3

Perfusion and permeability

Question 4

How does perfusion affect distribution of iv drugs

Answer 4

Drugs will be delivered to well perfused organs 1st, i.e., brain, kidney and liver.

Low perfused organ such as viscera, skin, and muscles receive drug slower

Question 5

4 Factors affecting drug distribution

Answer 5

Degree of ionization
Fat solubility
Size of molecules
Protein binding

Question 6

Define volume of distribution

Answer 6

The apparent volume that a drug needs to be distributed into given its plams concentration

The volume the drug dose needs to be diluted in to produce this plasma []

Question 7

What variables influence distribution

Answer 7

1. Movement out of vascular compartment
2. Plasma protein binding
3. Tissue binding