Exam 2 Drug Transporters

Question 1

Why is the extent of drug distributed to certain tissues may not correspond to drug concentration in blood due to drug transport in tissues?

Answer 1

1. although liver is a well perfused organ, some drugs do not readily access hepatocytes due to the need for uptake transporters
2. brain receives 5% of cardiac output, yet some drugs do not reach brain tissues due to the action of efflux pump transporters

Question 2

What are the different drug transport methods?

Answer 2

1. paracellular passive diffusion (between cells)
2. transcellular passive diffusion (through cell)
3. uptake transport (in)
4. endo/exocytosis
5. efflux transport (out)

Question 3

What are the role of transporters in drug disposition?

Answer 3

helps keep drugs out of the brain to protect it and some drugs into certain tissues

Question 4

What are the major drug transporters?

Answer 4

1. efflux transporter → pgp

2. uptake transporters → OATP (organic anion transporting protein) and PEPT1 (peptide transporter 1)