Lecture 4: Basic Principles of Pharm IV

Question 1

What are the purpose of biotransformation?

Answer 1

1. drug detoxification

2. prepare drug for exretion

Question 2

What are the sites of biotransformation?

Answer 2

1. liver

2. anywhere else in the body

Question 3

Hepatic Microsomal Drug Metabolizing Systems

Answer 3

1. both phase I and II processes
2. induction
3. inhibition

Question 4

Non-microsomal systems

Answer 4

1. other organs, plasma, red cells

2. usually phase 1 (eg: acetyl cholinesterase, alcohol dhydrogenase inhibition)

Question 5

What are phase I reactions?

Answer 5

1. drug oxidation
2. reduction
3. hydrolysis

Question 6

What is drug oxidation?

Answer 6

add oxygen or change the proportion of oxygen in the molecule, the most common metabolic transformation

Question 7

what is phase II rxn?

Answer 7

conjugation - synthesize a new molecule by combining the drug or metabolic product of phase I with a molecule provided by the cell

Question 8

what are the resulting molecules after phase II

Answer 8

1. larger
2. charged
3. water soluble
4. inactive

Question 9

biotransformation is

Answer 9

one method of clearing drug from plasma, ultimately terminating the drug effect

Question 10

alcohol and smoking induces

Answer 10

P450

Question 11

biotransformation of toxicants

Answer 11

can have a widespread influence on drug use

1. route of administration
2. dose
3. effectiveness
4. toxicity, safety
5. duration of effect

Question 12

phase 2 actions mainly take place in the

Answer 12

liver

Question 13

what happens in phase 2 rxn?

Answer 13

1. conjugation - synthesis of a new molecule, enxymes using endogenous substrates

Question 14

what are the 4 consequences of conjugation?

Answer 14

larger, charged, water soluble, inactive

Question 15

chronic alcoholics with liver dz will not do

Answer 15

the glucuronide formation

Question 16

the enzyme system may be a rate limiting step in the

Answer 16

clearance of drug from plasma
A. when metabolism is more important than renal elimination (lipid, soluble drugs)
B. Rate limiting step for clearance when enzyme is relatively slow

Question 17

if there is conc of drug is less than Km (efficient enzyme systems)

Answer 17

first order

Question 18

if the drug is saturated, the conc of drug is more than Km (inefficient enzyme systems = saturated)

Answer 18

zero order

Question 19

only free drug molecules are

Answer 19

filtered

Question 20

inhibiton

Answer 20

usually competitive

Question 21

saturation can occur at

Answer 21

therapeutic doses or with overdoses (changes primary processes to zero processes)

Question 22

drugs are reabsorbed by

Answer 22

1. passive

2. active

Question 23

two ways to enhance renal excretion?

Answer 23

1. forced diuresis

2. manipulate the pH or the urine - trapping of ionized drug

Question 24

alkalization (sodium bicarbonate for phenobarbital overdose) change urinary excretion by

Answer 24

4 fold to 6 fold

Question 25

clearance is

Answer 25

a combination of biotransformation and excretion

Question 26

factors that influence clearance?

Answer 26

1. body surface area
2. protein binding
3. cardiac output
4. renal function
5. hepatic function
6. blood flow to systemic organs