Week 12 / Pharmacology 1

Question 1

Q: What are the two processes initiated by drug taking?

Answer 1

A: Drug taking initiates two processes:
The action of the drug on the body.
The action of the body on the drug.

Question 2

Q: What is pharmacology?

Answer 2

A: Pharmacology is the study of the interaction between drugs and the living body.

Question 3

Q: What is pharmacodynamics?

Answer 3

A: Pharmacodynamics is the study of the effects of drugs on the living body and how these effects are produced.

Question 4

Q: What is pharmacokinetics?

Answer 4

A: Pharmacokinetics is the study of how the body deals with or handles drugs, including absorption, distribution, metabolism, and excretion.

Question 5

Q: What is pharmacotherapeutics?

Answer 5

A: Pharmacotherapeutics is the study of the use of drugs in the treatment and prevention of disease.

Question 6

Q: How do drugs act on the body?

Answer 6

A: Drugs interact with biological systems in ways that mimic or affect the natural chemical messengers or processes of the body.

Question 7

What are the 2 types of drug action ?

Answer 7

non-specific drug
specific drug

Question 8

What is non-specific drug action?

Do they have a structure-activity relationship ?

Does it require large doses to produce effects?

Answer 8

A: Non-specific drug action refers to drugs that act in a simple physical or chemical manner, such as antacids, osmotic diuretics, or osmotic laxatives.
These drugs do not have a specific structure-activity relationship

often require large doses to produce an effect.

Question 9

Q: What is specific drug action?

Do they have a structure-activity relationship ?

Does it require large doses to produce effects?

Answer 9

A: Specific drug action refers to drugs that act in a highly specific manner, interacting with or binding to specific macromolecular or cellular targets in the body, called “receptors.”

Drugs with specific action show a clear-cut structure-activity
relationship

produce biological effects at very low doses.

Question 10

Q: Can you provide examples of drugs with specific action?

Answer 10

A: Examples of drugs with specific action include phenylephrine, salbutamol, atropine, and digoxin.

Question 11

Q: What is the drug receptor concept?

Answer 11

A: The drug receptor concept states that most drugs produce their biological effects by interacting with specific macromolecules in the body, called receptors.

Question 12

Q: What is a receptor?

Answer 12

A: A receptor is the specialized component of a cell or organism that interacts with a drug, initiating the chain of biochemical events that lead to the drug’s observed biological effects.

Question 13

Q: What are drug receptors made of?

Answer 13

A: Drug receptors are protein or glycoprotein molecules.

Question 14

Q: Where are most drug receptors located?

Answer 14

A: Most drug receptors are located on the cell membrane. Examples include atenolol, chlorphenamine, cimetidine, and codeine.

Question 15

Q: Where are some drug receptors located?

Answer 15

A: Some drug receptors are located inside the cell. Examples include receptors for estrogen, testosterone, and vitamin D.

Question 16

What are the types of Drug targets or Receptors? [4]

Answer 16

Classical’ receptors
Ion channels
Enzymes
Carrier or transport proteins

Question 17

Q: What are the classical drug receptors?

Answer 17

A: Classical drug receptors are regulatory proteins or binding sites for endogenous or natural chemical messengers, such as neurotransmitters and hormones.

Question 18

Q: What are examples of drug targets that are ion channels?

Answer 18

A: Examples of drug targets that are ion channels include lidocaine, diazepam, and amiodarone.

Question 19

Q: What are examples of drug targets that are enzymes?

Answer 19

A: Examples of drug targets that are enzymes include NSAIDs, statins, and ACE inhibitors.

Question 20

Q: What are examples of drug targets that are carrier or transport proteins?

Answer 20

A: Examples of drug targets that are carrier or transport proteins include digoxin, proton pump inhibitors (PPIs), and selective serotonin reuptake inhibitors (SSRIs).

Question 21

Q: Why do drugs bind to receptors?

Answer 21

A: Drugs bind to receptors because the drug’s molecular structure and shape are similar to those of the natural chemical messengers the body produces to target those receptors.

Question 22

Q: What must occur for a drug to bind to a receptor?

Answer 22

A: There must be a complementary fit between the drug molecule and the binding site on the receptor.

Question 23

Q: How do drugs interact with receptors?

Answer 23

A: Drugs and receptors interact to form a drug-receptor (D-R) complex through a reversible chemical reaction.

Question 24

Q: What principle governs the drug-receptor interaction?

Answer 24

A: The drug-receptor interaction is governed by the Law of Mass Action.

Question 25

Q: How can drug concentration and biological effect be related?

Answer 25

A: Drug concentration and biological effect can be related to the fraction of receptors occupied by the drug.

Question 26

Q: What is the ‘Lock and Key’ relationship in drug-receptor interactions?

Answer 26

A: The ‘Lock and Key’ relationship is the basis of the selectivity of drug action, where the drug (the “key”) fits into the receptor (the “lock”) in a specific manner.

Question 27

Q: What are the two types of selectivity involved in the ‘Lock and Key’ relationship?

Answer 27

A: The two types of selectivity involved are:
Chemical selectivity – the ability of the drug to bind to specific receptors.

Biological or tissue selectivity – the ability of the drug to produce effects in specific tissues or organs.

Question 28

Q: How do drugs interact with receptors to form a complex?

Answer 28

A: Drugs and receptors interact to form a drug-receptor (D-R) complex through a reversible chemical reaction:
Drug + Receptor ⇌ Drug-Receptor Complex (D-R)

Question 29

Q: What factors influence the fraction of receptors occupied by a drug?

Answer 29

A: The fraction of receptors occupied by the drug is a function of:

The concentration of the drug in the biophase.
The equilibrium dissociation constant (K) for the drug-receptor complex.

Question 30

Q: What is the ‘Receptor Occupancy Theory’?

Answer 30

A: The ‘Receptor Occupancy Theory’ states that the drug effect is proportional to the fraction of receptors occupied by the drug.

Question 31

Q: What occurs when all receptors are occupied by the drug, according to the Receptor Occupancy Theory?

Answer 31

A: When all receptors in the system are occupied by the drug, the maximum drug effect (Eₙ max) occurs.