Pharmacokinetics and Toxicokinetics

Question 1

What are the three digestive steps that take place in the breakdown of drugs?

Answer 1

Disintegration
Dissolution
Absorption

Question 2

What are P-glycoproteins, and what is their role in drug metabolism?

Answer 2

ATP dependent efflux pumps located in the esophagus, stomach, and small/large intestines that pump drugs back into the GI lumen

Question 3

What happens to the first pass effect with large toxic drug ingestions?

Answer 3

Saturated

Question 4

What is the double peak phenomenon?

Answer 4

Excretion of the drug into the biliary system is eventually brought back into the systemic circulation via enteric uptake

Question 5

Does bound drug produce effects?

Answer 5

No

Question 6

What is the two compartment model of drug distribution?

Answer 6

Drug is preferentially taken up by certain tissues, then distributed throughout the body

Question 7

What is phase I metabolism? II?

Answer 7

I = asynthetic phase (formation of polar groups by hydrolysis, oxidation, reduction, dealkylation)
II - synthetic (conjugation with polar groups)

Question 8

What is the metabolite of codeine? What does this mean for patients who are fast metabolizers?

Answer 8

Morphine

If metabolize fast, then will turn drug into morphine

Question 9

What is zero order elimination?

Answer 9

Constant rate of elimination

Question 10

What is first order elimination?

Answer 10

Constant fraction of drug is eliminated, but actual rate is variable with drug concentration

Question 11

What is Emax and E50?

Answer 11

• Emax is the maximal effect a drug has

- E50 is the amount of drug that produces 50% of desired effect