Lec 2 - What is Pharmacology, Page 11- 18

Question 1

What is Pharmacology?

Answer 1

• The study of the effects of chemical agents of therapeutic value (drugs) or potential toxicity on biological system
• Relates to phyiology, biochemistry, cellular and molecular biology etc

Question 2

Name the 7 pharmacology sub-disciplines

Answer 2

1. Pharmacodynamics
2. Pharmacokinetics
3. Pharmacogenomics
4. Toxicology
5. Therapeutics
6. Pharmacoeconomics
7. Pharmacoepidemiology

Question 3

What are the goals of Pharmacology?

Answer 3

To understand all aspects of drug action and efficacy

-> to develop drugs/ treatment regimes that have selective (beneficial) actions without adverse effects

Question 4

What is a drug?

Answer 4

A chemical/ substance that is usually used to treat a disease/ condition
-> causes range of PHYSIOLOGICAL and BIOCHEMICAL (MOLECULAR) changes in a complex biological system that relate to its composition, structure and target

Question 5

When is a drug not a drug?

Answer 5

Drugs sold for treatment of disease must have regulatory approval from Medsafe/ FDA and must go through extensive evaluation procedures

1. Food supplements: not properly validated and approved for clinical use even though it may alleviate various conditions
   - > Must not make claims about therapeutic properties (only drugs can make those claims)

Question 6

Where do drugs come from?

Answer 6

1. Plants
2. Micro-organisms (fungi/bacteria)
3. Endogenous proteins/ steroids
4. Modification of endogenous compounds
5. Synthetic chemicals

Question 7

From 1981-2006, what is the % of new drugs were approved by the FDA as “natural”?

Answer 7

63%

Question 8

Examples of natural drugs

Answer 8

1. Paclitaxel (Taxol)
2. 1981-2002, 48 of 65 cancer drugs were natural products, based on natural products or mimicked natural products in some way

Question 9

2 examples of drugs made from extracts from plants and herbs

Answer 9

1. Opium poppy
   - Dried juice from seeds yields morphine (natural opiate)
   - Powerful painkiller and inducer of euphoria
2. Foxglove leaves
   - Contain digitalis (digoxin) which is a reversible inhibitor of Na/ K ATPase
   - Widely used to treat congestive heart failure
   - Lethal at high doses

Question 10

1 example of drug made from micro-organisms

Answer 10

Antibiotics

• Penicillin: prototypic b-lactam antibiotic
• Product of penicillium notatum (mold growing in Alexander Fleming’s lab in 1928)
• Interferes with bacterial cell wall synthesis

Question 11

3 examples of drugs made from the body itself (endogenous)

Answer 11

Hormones

1. Insulin -> treats diabetes
2. Thyroxine -> treats thyroid insufficiency
3. Growth hormone -> treats short stature

NB: most hormonal drugs are produced by recombinant DNA technology (proteins) or by chemical synthesis (steroids, peptides)

Question 12

2 types of drugs made by chemical modification of the body’s own hormones/ chemical regulators

Answer 12

1. Hormonal drugs
   - Ethinyl estradiol :readily absorbed form of oestrogen
   - Prednisolone: synthetic steroid w glucocorticoid like actions
2. Anti-cancer drugs
   - 6- mercaptopurine and 6 thioguanine
   - Modified base components of DNA/ RNA which interfere with DNA/RNA synthesis

Question 13

3 examples of drugs made from chemical synthesis of novel compounds with desirable properties

Answer 13

1. Indomethacin, celecoxib (COX inhibitors - NSAIDS)
2. Cimetidine- Histamine receptor modulator
3. Simvastatin- HMG- CoA reductase inhibitor

Question 14

Drugs that were developed by serendipity (by chance)

Answer 14

1. Antidepressants
   - Monoamine oxidase inhibitors and tricyclic antidepressants
   - Discovered from failed attempts to develop treatments for tuberculosis and pre-anaesthetic agents respectively
2. Cisplatin
   - Platinum containing drug used to treat number of cancers
   - Discovered while investigating the effects of electrical fields on bacterial cell growth
3. Viagra
   - Given to male Med students in study of hypotension

Question 15

Average cost of finding and marketing a new drug

Answer 15

$0.8 - 2 billion US

Question 16

Generic name

Answer 16

Related to the structure/ composition/ source of the drug
- preferred name for general use
- often have dimilar sounding endings that gives insight to type of drug
Eg. Selective COX-2 inhibitors
- celeCOXib, rofeCOXib, etoriCOXib, valdeCOXib

Question 17

Brand name

Answer 17

The drug company’s marketing name for the drug

Eg. Panadol for paracetamol, Dispirin for aspirin, Viagra for sildenafil

Question 18

Naming complications

Answer 18

1. Brand names can change over time as patents expire or pharmaceutical companies merge
2. Most drugs marketed by numberous names in diff countries Eg, Panadol (UK), Tylenol (USA)
3. Even generic names can differ between different countries
   Eg. Paracetamol (UK)= acetaminophen (US)

Question 19

How do drugs work?

Answer 19

1. Usually bind to a target to either activate or inactivate it (target usually are proteins)
Eg. Receptors, enzymes, ion channels, transporter molecules
Drugs that target ligands (Eg MABs) = a new class of drug

2.Other targets: DNA, RNA, lipids