Pharma Week 1 Flashcards
6 mechanisms of Drug action
1- binding to receptor
2- voltage gated ion channel
- local anethetics bolck Na gated ion channel in sensory neurons
- Ca channel blockers block Ca gated L type Ca channels in vascular smooth muscle & heart
- Oral antidiabetics ( sulphonylureas) block Atp sensitive K channels in insulin secreting B cells
3- Enzymes
Aspirin block Cox
Organophosphorus block cholinesterase
4- Direct chemical interaction
Antacids with gastric acid
EDTA with pb , Hg
5- physical or physicochemical interactions
Purgative Mgso4 , mannitol ( osmotic effect)
6- some drugs are structural analog -> 5- flourouracil
6 ligand gated ion channel
1- GABA
2- glycine
3- aspartate
4- acetyl choline at nicotinic R
5- 5HT3
6- glutamate
6 G protein coupled receptors
1- catecholamines
2- Ach at muscarinic
3- Angiotensin
4- Histamine
5- serotonin except 5HT3
6- Vasopressien
1 examples of tyrosine kinases linked receptors and 3 of intracellular receptors
1- insulin
1- thyroid
2- steroid
3- Vitamin D
2 causes of binding the antagonist irreversible
1- the affinity is so high that the receptor is unavailable to bind to the agonist
2- the antagonist form strong covalent bond
Eaxmple of Non competitive antagonists
Pneoxybenzamine
Write 4 types or receptors and the character of this type
1- ion channel-> speedy
2- G protein -> amplifier
3- tyrosine kinase( enzyme linked)-> multiple action
4- intracellular-> long lasting
Example and 3 causes of down regulation
Uses B2 agonist in bronchial asthma
1- decrease the sensitivity
2- decrease synthesis of Receptors due to feed back regulation
3- Decrease effectiveness
( diminished response due to decreased number of receptors)
Example of change in the number of receptors by other substances and 2 Examples of change by disease
1- thyroid Hs increase the sensitivity to catecholamines
1- myasthenia gravis
2- form of insulin resistance diabetes mellitus
2 Examples of cross tolerance
1- morphine & heroin
2- alcohol & barbiturates
What is intolerance
Great susceptibility to drug action
2 Examples of pharmacodynamics drug drug interactions
1- Morphine & Naloxone : compete with each other on opoid receptors, naloxone is used to treat acute morphine overdose
2- K and digoxin : k is used to overcome digoxin toxicity
3 Examples of idiosyncratic
1- prolonged apnea caused by succinylcholine
2- warfarin inhibit formation of active form of vitamin K by inhibiting the epoxide reductase
3- some oxidant drugs e.g sulphonamide,aspirin , chloroquine,primaquine cause hemolytic anemia in G6PD by decrease reduced glutathione then increase peroxidase that damage the cell membrane
