WEEK2: INTRODUCTION TO PHARMACOLOGY AND ACTIONS OF DRUGS

Question 1

What is pharmacology?

Answer 1

Pharmacology can be described as the study of the effects of drugs on the function of living systems.

Question 2

What is a drug?

Answer 2

A drug is any chemical substance of known structure, which, when administered to a living organism, produces a biological effect.

Question 3

What is medicine?

Answer 3

Medicines is a drug administered with the intention of producing a therapeutic effect.

Question 4

What is an Active Pharmaceutical Ingredient (API)?

Answer 4

Biologically active chemical within the drug

Question 5

Name the Excipients (Inactive Pharmaceutical Ingredients) found in drugs.

Answer 5

*Diluents and fillers (Bulking agents)
* Coatings (Improve stability & control disintegration)
* Flavorings and colorants: Product appeal
*Preservatives: Prevent microbial growth.

Question 6

What are brand names?

Answer 6

Chosen by a manufacturing company.

Question 7

State the ROUTE OF ADMINISTRATION .

Answer 7

 Enteral
 Parenteral
 Inhalation
 Topical

Question 8

What is pharmacodynamics?

Answer 8

What the drug does on the body?

Question 9

Outline 3 main things covered by Pharmacodynamics.

Answer 9

 Pharmacologic effects of drug on the body
 Mechanisms of drug action
 Relationship between dose & effect

NOTE: Effect can be therapeutic/ toxic

Answer 10

1.PHYSICAL & CHEMICAL INTERACTIONS

*Antacids (bases)

*Osmotically active agents (shift water between Compartments)

*Chelating agents (bind to and absorb metal ions)

*Activated charcoal (powerful adsorbent)

2.

Question 11

WHAT IS A COMPETITIVE REVERSIBLE INHIBITORS?

Answer 11

A competitive inhibitor resembles the endogenous substrate.

It competes with the substrate for binding to the
active site.

Question 12

WHAT ARE NON-COMPETITIVE REVERSIBLE INHIBITORS ?

Answer 12

 The drug does not resemble the substrate.
 It binds to the allosteric site, causing a confirmational
change that renders the enzyme ineffective.

Question 13

What are ion channels?

Answer 13

Protein-coated pore in the cell membrane that
regulates diffusion of ions

Question 14

WHAT ARE IRREVERSIBLE INHIBITORS?

Answer 14

 Bind to enzymes with covalent bond.

Question 15

What are transport carriers?

Answer 15

Transport carriers.

 Translocate substrates across the membrane by facilitated diffusion/ active transport.

 Antidepressants act by increase the monoamine levels in the brain by inhibiting NERT and SERT

Question 16

What is a receptor?

Answer 16

Receptor: the component of a cell or organism that interacts with a drug and initiates the chain of events
leading to the drug’s observed effects.

Question 17

STATE the 4 main classes of receptors.

Answer 17

1. Ligand-gated ion channel receptors

Nicotinic receptors
 Acetylcholine  Nicotine

GABA receptors
 Benzodiazepines  Barbiturates  Ethanol

2. G-protein coupled receptors.
    Gs , Gi and Gq protein coupled receptors
3. Enzyme-linked receptors
    Insulin  Growth factors  Cytokines
4. Intracellular receptors:
    Steroid hormones  Thyroid hormones  Vitamin

Question 18

State the 2 types of dose response curves.

Answer 18

 Graded dose response curves
 Quantal dose response curve

Question 19

Describe the following components of the Grade dose response curve.
1.ED50
2.Potency
3.Effectiveness

Answer 19

ED50 (Median effective dose):

Potency (Amount): Relative amount of the drug needed to produce a specific response.

Efficacy (Effectiveness): It is how well the drug produces a biologic response.

Question 20

What is intrinsic activity?

Answer 20

The ability of the drug to produce a pharmacologic effect.

Question 21

What is an agonist?

Answer 21

A substance which initiates a physiological response when combined with a receptor.

Question 22

Describe the 3 types of agonist.

Answer 22

FULL AGONIST: Maximum possible biologic response

PARTIAL AGONIST: Submaximal biologic response

INVERSE AGONIST: Decreases the activity of receptor below basal level (Opposite response)

Question 23

What is an antagonist?

Answer 23

Do not initiate any response.

A substance which interferes with or inhibits the physiological action of another.

Question 24

What is a competitive antagonist?

Answer 24

 Compete for the same binding site with the agonist
 Form non-covalent bond with the receptor
 Overcome by increasing the dose of the
agonist

Question 25

What is a non-competitive antagonist?

Answer 25

*Decrease efficacy, but not potency
* Cannot be overcome by increasing the dose of the agonist.

 Examples include irreversible and allosteric antagonists.

Question 26

What is therapeutic window?

Answer 26

The therapeutic window of a drug is the range of dosage or time interval of a drug or treatment that provides safe and effective therapy.

Question 27

Describe the following features of the quantal dose response curve.

1.Median therapeutic dose
2.Median toxic dose

Answer 27

Median therapeutic dose
* The dose at which 50% of individuals exhibit the specified quantal effect.

Median toxic dose
* This is the dose at which some clinically relevant toxic effect is reported in 50% of the tested population.