Block A Flashcards
(33 cards)
What is a pharmacological antagonist?
When a drug counteracts another by acting on the same receptor type.
What is irreversible competitive antagonism?
Where the bond between antagonist and receptor is so strong that even increasing conc of agonist won’t displace it.
what is non-competitive antagonist?
Antagonists which bind to another site and change the structure of the active site.
What does pharmacology refer to?
The mechanism of action of drugs in living tissue.
What is a drug?
A substance which modifies the effect of living tissue.
Who said “all things are poisons, for there is nothing without poisonous qualities. It is the does which makes a thing a poison.”
Paracelsus.
What is Botulinum toxin?
Gram-positive, rod shaped, anaerobic, spore forming bacteria.
Why is Botox a good example of the importance of dose size?
While it is one of the most deadly substances in the world it also has a wide range of therapeutic effects such as treating migraines, misaligned eyes, ect..
What are the two types of drug toxicity?
Iatrogenicity- Capacity to produce disease from side effects.
Teratogenicity- Capacity to produce abnormalities of the unborn child or foetus.
What went wrong with Thalidomide?
It has two isotopes:
R-Sedative effect.
S-Teratogenic effect.
How are drugs studied?
High throughput screening- Thousands of drugs screened per day.
Ex Vivo- Tissue samples used to test drug, more physiological relevant.
In Vivo- Animal model testing, patient clinical trials.
Name some drug targets.
-Ion channels
-Enzymes
-Transporters/ carriers
-Receptors
What is a receptor.
Recognition molecules composed of regulatory proteins. May recognise and response to outside stimulus.
What are the biggest targets for clinically effective drugs?
1)Enzymes
2)GPCR
3)Ion channels
What molecule does Salbutamol mimic?
Adrenaline.
What does salbutamol do?
-Interacts with a Beta 2 adrenoceptor. (GPCR)
-Mechanism occurs which activated adenylate cyclase
-Causes increases in cyclic AMP
-Inhibits release of calcium in cell
-Calcium is important for constriction, therefore allows airways to relax.
What causes hay fever?
-Pollen binding to IgE antibodies.
-Antibodies activate mast cells.
-Mast cell releases histamine.
-Histamine causes inflammation and swelling.
What receptor does histamine activate?
Histamine H1 receptor.
What are the effects of histamine binding to the H1 receptor?
Capillary widening-Increased blood flow
Increased permeability-Fluid released into tissue
Attraction of leukocytes-Extravasation of leukocytes to site of injury
systemic response-Fever and proliferation of leukocytes
What type of drug are antihistamines?
H1 receptor antagonist.
Give some examples of drugs acting as antagonists.
Beta blockers (B1 antagonist)-For heart arrhythmia
H2 receptor antagonist-Treats stomach ulcers
Angiotensin 2 receptor antagonists- Lower blood pressure
Purinergic receptor antagonists-Treats heart attacks.
How does aspirin work?
Works on the enzyme cyclo-oxygenase as an inhibitor (COX inhibitor)
What does the enzyme Cyclo-oxygenase do?
Oxidises the arachidonic acid into a cyclical compound into PGH2.
PGH2 is then converted into either TXA2 or PGE.
What are the two types of COX enzyme that aspirin inhibits?
COX-1 enzyme-Inactivates
COX-2 enzyme-Switches the activity to produce anti-inflammatory lipid products.
