P450

Question 1

What is the major difference between pharmacodynamic and pharmacokinetic interactions?

Answer 1

Pharmacodynamic interactions are those involved with a drug (or drugs) and the target. Pharmacokinetic interactions are those that effects drug availability, including P450 clearance rates

Question 2

Which interactions are predictable according to a drug’s mechanism of action: pharmacodynamic or pharmacokinetic?

Answer 2

Pharmacodynamic only

Question 3

How often is a chief complaint related to a patient’s drug regimen?

Answer 3

5% - not sure the number needs to be memorized, just know that these causes are common enough that you will see them on a regular basis

Question 4

List 3 ways that a chief complaint can hint at being drug induced:

Answer 4

The wrong effect is observed, the effect is not proportional to the dose, or a symptom is not common to the patient’s normal disease state

Question 5

There are 5 major degradation products of acetaminophen (esp. overdose) listed below. Which is toxic? Treatment with NAC/glutathione breaks down the toxin into what metabolites from the list?
Cysteine
Glucuronide
Mercapturic acid
NAPQI
Sulfate

Answer 5

NAPQI, breaks down into Cysteine and Mercapturic acid

Question 6

What drug metabolism process is non-P450 dependent? What nationality typically performs it quickly? Slowly?

Answer 6

Acetylation by n-acetyltransferase
Japanese - fast
Scandinavians - slow

Question 7

What molecule is the driving force for most clinically relevant pharmacokinetic interactions?

Answer 7

Cytochrome P450

Question 8

What is the mechanism of a P450 inducer?

Answer 8

The inducing drug upregulates enzyme production in the liver

Question 9

What is the mechanism of a P450 inhibitor?

Answer 9

Active site blockade