Drug metabolism

Question 1

What is Phase 1 metabolism?

Answer 1

Involves hydrolysis, Oxidation and Reduction. Increases polarity of compound and provides an active site of Phase 2

Question 2

What enzymes carry out Phase 1 metabolism?

Answer 2

P-450 enzymes

Question 3

What is Phase 2 metabolism?

Answer 3

Involves conjugation, which inactivates most drugs but some stay activated
Increases water solubility to make excretion easier
Glucuronic acid, gluthianone, sulphate and acetate are added to metabolites created in Phase 1

Question 4

What factors affect metabolism?

Answer 4

Other drugs/substances
Genetics
Hepatic blood flow
Liver disease
Age
Sex
Ethnicity

Question 5

How does Enzyme induction affect metabolism?

Answer 5

Drug metabolising enzymes are induced by some drugs/substances such as alcohol and smoking, so these cause drugs to be metabolised quicker and so reduce their effect.

Question 6

How does Enzyme Inhibition affect metabolism?

Answer 6

Some drugs inhibit drug metabolising enzymes so they are not metabolised very quickly, and increase their effect. Include clarithromycin, erithromycin

Question 7

How does genetics affect metabolism?

Answer 7

Drug metabolising enzymes are expressed in different forms. Genetics can cause these enzymes to be enhanced or reduced, and therefore both affect metabolism.

Question 8

How does age affect metabolism?

Answer 8

Drugs are metabolised faster in children and teenagers than in adults.