Introduction (lesson one Principles of Drug action)

Question 1

What is Pharmocology divided into?

Answer 1

Pharamocokinetics and pharamocodynomics

Question 2

What is Pharmocokinetics

Answer 2

The movement of the drug around the body and how the body effects the drug.

The study of the time course of drugs and their metabolites in the body

Question 3

What is Pharmocodynomincs ?

Answer 3

The effect the drug has on the body.

Question 4

Name the five factors that have an impact upon pharmocokinetics.

Answer 4

1. Adminstration
2. Absorbtion
3. Distrbution
4. Metabolism
5. Elimination

Question 5

Define metabolism.

Answer 5

The drug becomes chemically altered.

Question 6

Name 7 ways a drug can be adminstered?

Answer 6

• Oral (plus buccal and sub-lingual)
• Rectal
• Skin (topical)
• Lungs (plus nose)
• Eye, Ear
• Urethra

Question 7

Name the 6 ways a drug can be injected?

Answer 7

• Intramuscular
• Subcutaneous
• Intradermal
• Intraperitoneal
• Intrathecal
• Intra-arterial

Question 8

What adminstration route is a drug which will experience first pass metabolism likely to take?

Answer 8

Oral

Question 9

Where does first pass metabolism take place?

Answer 9

Liver

Question 10

What are the three factors that determine how much of the drug reaches the target via administration?

Name a possible 4th factor that my determine this?

Answer 10

•Lipid solubility
•Area available for absorption
•Possible specific carriers
First Pass Metabolism

Question 11

Why doesn’t the oral method recieve the same peak that the intravenous method does?

Why does the venous method deliver a higher peak but leave the blood after not so long?

Answer 11

Absorbortion from the GI tract and First Pass metabolism

Because it is injected straight into the blood and it is metabolised and excreted faster because of this.

Question 12

What is bioavailbity?

Answer 12

Can quantify how well drug has been absorbed and how well it will reach it’s site of action.

Question 13

How do you calculate Bioavailability (F)?

Answer 13

Amount of drug absorbed in systemic circulation after oral admin/ amount of drug absorbed when the same dose was administed orally

Question 14

What is the half life of a drug ?

Answer 14

•The time it takes for the plasma drug concentration to fall to half its original value.

Question 15

How do you calculate clearance of a drug?

Answer 15

Rate of Elimination/Plasma drug conc

Question 16

Name the concept of First order kinetics?

Answer 16

•Rate of removal depends on how much drug is present (more drug ↑rate of removal; less drug ↓rate of removal)

Question 17

Why are individuals asked to take drugs several times a day?

Answer 17

To ensure there is enough of the drug in the body to ensure that there is theraputic effects.

Question 18

What must drugs be taken at regular intervals?

Answer 18

To ensure there is enough of the drug present in the plasma for theraputic effect to compensate for the loss of drug quantity that may be caused by first pass metabolism or adminstration.

Question 19

What happens if too much drugs are taken in short window of time?

Answer 19

This can have toxic effects.