Introduction To Pharmacology - Tutorial 4

Question 1

Define the three different drug names

Answer 1

• Chemical name: describes the chemical composition, e.g. N-acetyl-p-aminophenol
• Generic name: the official name listed in publications and used for prescribing. E.g paracetamol
• Trade (brand name): marketed name, E.g. Panadol

Question 2

Define the term pharmacodynamics

Answer 2

The effect of the drug on the body

Question 3

Define the terms agonist & antagonist

Answer 3

• Agonist - binds to and activates receptor
• Antagonist - binds to and deactivates receptor

Question 4

Define the term pharmacokinetics

Answer 4

How the body affects a specific drug after administration

Question 5

Name and describe the four pharmacokinetic processes in correct sequence

Answer 5

1. Absorption - refers to the passage of medications from the site of administration into the blood.
2. Distribution - refers to the movement of the drug from the blood to the body’s tissues.
3. Metabolism - is the process of chemical modification of the drug
4. Excretion - is the removal of the drug from the body

Question 6

State three factors that would influence each of the four pharmacokinetic processes

Answer 6

1. Absorption:
   
   • Route of delivery
   • Body surface area
   • Blood flow to the area of absorption
2. Distribution:
   
   • Tissue binding
   • Cardiac function
   • Capillary permeability
3. Metabolism:
   
   • Genetics
   • Age
   • Disease states
   • Environmental factors (e.g diet)
4. Excretion:
   
   • Sweat
   • Bile
   • Breast milk

Question 7

State five ways that drugs can be excreted

Answer 7

• Sweat
• Bile
• Breast milk
• Faeces
• Expired Air

Question 8

Explain hepatic first pass effect & drug bioavailability

Answer 8

• Hepatic first pass effect - orally admistered drugs travel first through the portal system and liver before entering the systemic circulation - a variable amount of drug may be extracted before entering the systemic circulation

Drug bioavailability - The proportion of the administered dose that reaches the systemic circulation intact - drugs delivered intravenously have 100% bioavailability