sheet pharma # 1

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sheet pharma # 1

Post by Shadi Jarrar on 24/9/2010, 11:27 pm

بسم الله الرحمن الرحيم
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history of pharmacology

from early life of human we dealing with drugs but these drugs were herbal medicine
herbal medicine still use until 18th century scientists produced something called pharmacology ,by this science they produced the active ingredients(like morphine) from herbs ,then they discovered aspirin
In 1930-1940(exponential growth of science) the scientists understood mechanism of action and they started produce drugs

Responsibility of pharmacology
responsibility important when u describe drugs and when u treat patients
We responsible about anything that the drug will produce to the patient , so think right before u describe drug to the patient because u describe a toxic material
Note : all drug are toxin and its depend on the dose of drug if the dose is huge , drug will cause toxin
U must know that everybody react with drug differently
u need to know many thing about drug in order to be able to prescribe it:
1-name of the drug (Scientific name(
eg: , augmatin , cloram ,amoxidarm all of them have same scientific name which is amoxcecellin , but the different in their trade names so we don't deal with trade name we dale with scientific name
**I am not sure from drugs spelling**
2. use of drugs(effect on the body as effect and side effect)
U must till the patient the side effect of drug**
3-knowledge of intra indication
For example u don’t give proven to a pregnant lady because it cause teratogenic effect , and u can't give aspirin to children because it cause anaphylactic shock to them
**never describe drug except u know everything about it
4. how the medication is to be administrated
( طريقة إعطاء الدواء Means dosage form (
** u must till your patient how to take the drug
we have many ways to give the drug:
orally , rectally , intravenously , intramuscularly , inhalation
5.why the medicine has been prescribe for this particular patient
By knowing all that u can avoid many series adverse drug effect in your patient

Pharmacology divide into 2 parts :
1.dynamic mechanisms of action of the drug
2.kinatic include a)absorption
b)distribution
c)metabolism
d)elimination
pharmacology meaning :- study of biochemical and physical aspect of drugs effect including absorption ,distribution , metabolism , elimination and specific mechanism of action
(this is v.rigid definition of pharmacology)
Simple meaning :- what dose substances that u take to ward your body dose to your body
(the definition not important)

Mechanism of action:
-every drug has its mechanism of action
-most drugs exsert their effect by interacting with a specialized target of macromolecules (receptors)
-Drug bind with a receptor in a special part called binding site , at this site conformational changes occur and cause transduction of biological effect into a response
( remember key and lock)
We have fundamental properties that affect on action btwn drug and receptor :1. 3 dimensional structures
2. charges for example DNA has negative charge so we use a positive or neutral drug charge to affect it
Now we have 4 types of mechanisms of action:
First u remember that we divide drugs into 2 types
type A : u must know every thing about it (mechanism of action)
type B : u must know side effect about it
types of mechanisms of action:
1. ligand-gated ion channels .
they responsible for regulation of the flow of ions across cell membranes
The activity of these channels is regulated by the binding of a ligand to the channel
For example when u use local anestuetices they locking Na channels and that means stop action potential and stop pain .

2 . G protein-coupled receptors
These receptors are comprised of a single peptide that has seven membrane – spanning regions, and these receptors are linked to a G protein
Binding of the appropriate ligand to the extracellular region of the receptor activates the G protein so that GTP replaces guansosine diphosphate (GDP) on the α subunit. Dissociation of the G protein occurs, and both the α – GTP subunit and the by subunit subsequently interact with other cellular effectors, usually an enzyme or ion channel.

3. enzyme – linked receptors
The most common enzyme linked receptors is tyrosine kinase
Upon binding of the ligand to receptor subunits, the receptor undergoes conformational changes, converting from its inactive form to an active kinase form.
The activated receptor autopgosphotylates, and phosphorylates tyrosine residues on specific proteins.

4. intracellular receptors
These kind differs from other in that receptor is entirely intracellular and the ligand must deffuse into the cell to interact with the receptor .
This places constraints on the physical and chemical properties of the ligand in that it must have sufficient lipid solubility to be able to move across the target cell membrane.

Properties of these types of receptors :
1.actions occurs toward DNA and it increase or decrease the transcription
2. they need times
(these explains from the book)

**drugs have to measured within cells to produce a biological effect which always be link with transcription and translation.
due to difference in genes **effect of drug on patients is different
btwn them
**when u give a patient dose of drug , it has effect if u increase the dose, the effect will increase until it reached to the maximum (mean all receptors are saturated)
**when we reached saturated the drug lose its effect that’s mean we must give the patient anther drug

Potency and efficacy
Potency ; a measure of the amount of drug necessary to produce an effect of a given magnitude
We use it to compare the potent of tow drug by Emax
For example morphine and aspirin
Emax of morphine is more than Emax of aspirin, so morphine is more potent than aspirin
Potency measure
The concentration Producing an effect that is 50% of a maximum is used to measure potency , it commonly designated as the EC50.
Drug that has less EC50 is more potent than the other because less drug is needed to obtain 50% effect.

In this figure drug A is more potent than drug B because EC50 of drug A is less than EC50 of drug B.
Efficacy: the ability of a drug to illicit a physiologic response when it interacts with a receptor.
We use it to describe one drug
For example we have many antiemetics (مضاد القيء) we arrange them by efficacy as every one deal with special level of vomiting . efficacy more means the drug is more affect on patient
It is dependent on 1.the number of drug-receptor complexes formed
2.the efficiency of the coupling of receptor activation to cellular responses
**Coupling means binding of receptor and transduction of biological effect
For example insulin and morphine produce same biological effect but have different level of efficacy, morphine give to any patient but insulin give to a caners patient

Antagonism and agonism :
Agonism: a biological response that produced when a drug bind to a receptor
Antagonism :is drugs that decrease the actions of another drug or endogenous ligand
We have 4 types of antagonism : a) pharmalogical antagonism
two drugs one has activated effect on a receptor but the other has inhibition effect on the same receptor
for example propanol has inhibition effect on B1, but adrenalin has activated effect on B1
b) physiological antagonism
eg: sympathetic and parasympathetic
c) chemical antagonism
eg : agent for cancers patients if it takes with milk it doesn’t work because ca bind with it and not allow it to bind with its receptor.




Done by : baraah al –khateeb
Lec # 1, 20/09/2010
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Shadi Jarrar
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تاريخ التسجيل : 2009-08-28
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