Pharmacology principles

Question 1

Minimum effective concentration

Answer 1

Concentration of the drug needed for the drug to have an effect on the body. (critical concentration)

Question 2

Maximum tolerated concentration

Answer 2

The maximum concentration of a drug that can be tolerated by the body without any adverse effects

Question 3

Clearence

Answer 3

Volume of plasma cleared of the drug per unit of time

Question 4

First order kinetics

Answer 4

The rate of elimination is directly proportional to drug concentration

Question 5

Zero order kinetics

Answer 5

The rate of elimination is not proportional to drug concentration.

Question 6

Rate of elimination is a product of?

Answer 6

Plasma concentration and clearence

Question 7

Steady state

Answer 7

Rate of elimination=rate of administration

Question 8

IV dosing to steady state graph

Answer 8

Smooth curve up and plateauing when it reaches steady state.

Question 9

Oral dosing to steady state graph

Answer 9

Fluctuates around steady state because you are not constantly being given the drug.

Question 10

Volume of distribution

Answer 10

The volume into which a drug appears to be distributed with a concentration equal to that of plasma

Question 11

Polar metabolites are more readily excreted. True or false.

Answer 11

True

Question 12

Phase 1 metabolism

Answer 12

Adding a chemically reactive handle via oxidation, reduction or hydrolysis. Making the drug more polar.

Question 13

Phase 2 metabolism

Answer 13

Adds an endogenous compound increasing the polarity e.g. glucorindation

Question 14

CYP450 mono-oxygenases

Answer 14

Family of haem proteins located in the endoplasmic reticulum of liver hepatocytes. They mediate phase 1 reactions.

Question 15

In CYP3A4, what do the 3,A and 4 represent?

Answer 15

3- gene family
A- gene subfamily
4- individual gene.

Question 16

What do phase 2 reactions usually result in, where do they occur and give an example?

Answer 16

They usually result in inactive products. It occurs in the liver and an example is glucorindation. This is the adding of glucuronic acid to electron rich atoms on the substrate.

Question 17

Renal excretion via filtration

Answer 17

Only unbound drugs can pass through the glomerulus. Have to have a molecular weight of less than 20,000.
Clearance by filtration= glomerular filtration rate x fraction of unbound drug

Question 18

Two transporters that transport drugs into the nephron

Answer 18

Organic anion transporter and organic cation transporter.

Question 19

Pro’s and cons of OAT or OCT

Answer 19

Pro’s- protein bound drugs can be excreted.

Con’s- They are saturable. Substances may compete with each other

Question 20

Give examples of what the organic anion transporter may excrete

Answer 20

Acidic drugs e.g. penicillin, uric acid, thiazides

Question 21

Give examples of what the organic cation transporter may excrete

Answer 21

Basic drugs e.g. morphine

Question 22

Factors that influence reabsorbtion

Answer 22

Lipid solubility- higher the lipid solubility- more reabsorption
Polarity- more polar, more likely it it to be excreted
Urinary flow rate
Urinary pH- more acidic- basic drugs will be excreted. More basic- acidic drugs will be excreted