Lec 2 - What is Pharmacology, Page 11- 18 Flashcards
(19 cards)
What is Pharmacology?
- 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
Name the 7 pharmacology sub-disciplines
- Pharmacodynamics
- Pharmacokinetics
- Pharmacogenomics
- Toxicology
- Therapeutics
- Pharmacoeconomics
- Pharmacoepidemiology
What are the goals of Pharmacology?
To understand all aspects of drug action and efficacy
-> to develop drugs/ treatment regimes that have selective (beneficial) actions without adverse effects
What is a drug?
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
When is a drug not a drug?
Drugs sold for treatment of disease must have regulatory approval from Medsafe/ FDA and must go through extensive evaluation procedures
- 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)
Where do drugs come from?
- Plants
- Micro-organisms (fungi/bacteria)
- Endogenous proteins/ steroids
- Modification of endogenous compounds
- Synthetic chemicals
From 1981-2006, what is the % of new drugs were approved by the FDA as “natural”?
63%
Examples of natural drugs
- Paclitaxel (Taxol)
- 1981-2002, 48 of 65 cancer drugs were natural products, based on natural products or mimicked natural products in some way
2 examples of drugs made from extracts from plants and herbs
- Opium poppy
- Dried juice from seeds yields morphine (natural opiate)
- Powerful painkiller and inducer of euphoria - 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
1 example of drug made from micro-organisms
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
3 examples of drugs made from the body itself (endogenous)
Hormones
- Insulin -> treats diabetes
- Thyroxine -> treats thyroid insufficiency
- Growth hormone -> treats short stature
NB: most hormonal drugs are produced by recombinant DNA technology (proteins) or by chemical synthesis (steroids, peptides)
2 types of drugs made by chemical modification of the body’s own hormones/ chemical regulators
- Hormonal drugs
- Ethinyl estradiol :readily absorbed form of oestrogen
- Prednisolone: synthetic steroid w glucocorticoid like actions - Anti-cancer drugs
- 6- mercaptopurine and 6 thioguanine
- Modified base components of DNA/ RNA which interfere with DNA/RNA synthesis
3 examples of drugs made from chemical synthesis of novel compounds with desirable properties
- Indomethacin, celecoxib (COX inhibitors - NSAIDS)
- Cimetidine- Histamine receptor modulator
- Simvastatin- HMG- CoA reductase inhibitor
Drugs that were developed by serendipity (by chance)
- Antidepressants
- Monoamine oxidase inhibitors and tricyclic antidepressants
- Discovered from failed attempts to develop treatments for tuberculosis and pre-anaesthetic agents respectively - Cisplatin
- Platinum containing drug used to treat number of cancers
- Discovered while investigating the effects of electrical fields on bacterial cell growth - Viagra
- Given to male Med students in study of hypotension
Average cost of finding and marketing a new drug
$0.8 - 2 billion US
Generic name
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
Brand name
The drug company’s marketing name for the drug
Eg. Panadol for paracetamol, Dispirin for aspirin, Viagra for sildenafil
Naming complications
- Brand names can change over time as patents expire or pharmaceutical companies merge
- Most drugs marketed by numberous names in diff countries Eg, Panadol (UK), Tylenol (USA)
- Even generic names can differ between different countries
Eg. Paracetamol (UK)= acetaminophen (US)
How do drugs work?
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
