12. CIS Biotransformation

Question 1

What would happen to the half life of a drug if a man is a smoker?

Answer 1

Clearance is increased because smoking is an inducer, increasing liver enzymes, causing the drug to be metabolized faster

Question 2

What can phenobarbitol do?

Answer 2

It is an inducer, increases clearance of drug

Question 3

If a patient is taking warfarin and heparin post-surgery, and experiences excessive bleeding, what pharmacodynamic polymorphism could be expected?

Answer 3

Vitamin K Epoxide Reductase deficiency

NOTE: CYP2C9 processes warfarin

Question 4

A italian person presents with a UTI, and is given a sulfa drug. The infection goes away, however he now is experiencing bleeding in his urine. What polymorphism occured?

Answer 4

G6Pdeficiency - most common defect can lead to RBC lysis d/t a reduction of NADPH

Question 5

What is the main cause of hemolysis in the previous case about the italian man?

Answer 5

Sulfa drug and G6PD, sulfa causes hemolysis of RBC

Question 6

What could cause the amount of drug in blood to increase, along with Tmax and the area under a curve, as compared to someone not experiencing that?

Answer 6

Drinking grapefruit juice! inhibits liver from breaking down drugs