Introduction to Pharmacology Flashcards

1
Q

What is Pharmacology

A

it is the study of how substances interact with living systems and processes. occurs by binding or activating or Inhibiting body processes

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2
Q

Medical Pharmacology

A
  • It is the science of substances used to prevent,
    diagnose and treat diseases.
  • Aimed at understanding the action of drugs or
    chemicals on individual organisms which includes
    both therapeutic and toxic effects
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3
Q

Toxicology

A
  • Branch of Pharmacology that deals with the undesirable effects of chemicals on living
    systems, from individual cells to humans to a complex ecosystem.
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4
Q

Environmental Toxicology

A
  • It refers to the effects of chemicals on all organism and their survival in groups and as a species.
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5
Q

Pharmacogenetics

A
  • This refers to the study of genetic influences in response to a drug.
  • Not all drugs will have the same effect on an individual.
  • It focuses on the Familial-induced hepatic drug reaction where affected individuals show an abnormal adverse response to a class of drug.
  • It now covers a broader variation in drug response where the genetic basis is more complex.
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6
Q

Pharmacogenomics

A
  • It refers to the relation of an individual’s genetic
    make up to his/her response to specific drugs.
  • The recent term overlaps with pharmacogenetics.
    This is greater in the use of genetic information to
    guide the choice of drug on individual basis.
  • It also refers to the difference of individuals with
    their response to therapeutic drugs that can be
    predicted from their genetic make-up.
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7
Q

how does rapid or slow acetylators affected by isozanoid acetylation?

A

Rapid acetylators will
have a lesser level of the drug and lesser
risk for toxicity than those who are slow
acetylators. Most Asians are considered
rapid acetylators of isoniazid.

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8
Q

Pharmacoepidemiology

A
  • Is the study of drug effects at population level.
  • It is concerned with the variability of drug effects
    between individuals and at a population level.
  • It also takes into account the patient’s compliance
    and other factors that apply when drugs are used
    under real life situations
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9
Q

Pharmacoeconomics

A
  • Is the branch of economics that aims to quantify in economic terms the cost and benefit of drugs that are used therapeutically.
  • One objective of basic pharmacology is to identify a drug based on its safety, adverse effect, necessity, and efficacy.
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10
Q

Drug –

A

defined as any substance that brings about a
change in biological function through its chemical actions.
- Many drugs found in nature are alkaloids.
- A drug should bind to a receptor for it to develop
its effect.

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11
Q

Physical nature of the drugs

A
o Often determine as the best route of
administration.
 Solid form at room temperature
(e.g. Aspirin, Atropine) – oral
 The liquid form (e.g. Nicotine,
Ethanol) – parenteral or oral
 Gaseous form (e.g. Nitrous
Oxide) – Inhalation
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12
Q

Drug size

A

o Affects clearance and distribution.
molecular weight between 100 MW – 1000 MW.

(Lithium ion = MW 7) and MW (Alteplase [t-PA] = MW
59,050).
o A molecule should in most cases be at
least 100 MW units in size because if that
the drug is very small it can bind to different
receptors thereby reducing its selectivity.
o This also determines the ability of the
drugs to pass the blood-brain barrier as
well as the placental barrier.
o Drugs much larger than MW 1000 do not
diffuse readily between compartments of
the body.

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13
Q

Drug reactivity and drug-receptor bonds

A

o Drugs interact with receptors by means

of chemical forces or bonds

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14
Q

Covalent

A
 strongest and
irreversible;
 most antagonists form
covalent bonds,
specially irreversible
antagonists (e.g.
Binding of Proton pump
inhibitors (PPIs) to
Hydrogen-Potassium
ATPase forms a
covalent bond thereby
inactivating that proton
pump which can last for
18-24 hours.)
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15
Q

Electrostatic bond

A

more common but
weaker than covalent
bond.

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16
Q

Hydrophobic

A
weakest and important
in the interactions of
highly lipid-soluble drugs
with lipids of cell
membranes
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17
Q

Drug shape

A
o Complementary to the receptor site in the same way that the key is
complementary to that of the receptor
site.
o Involves chirality and stereoisomerism
e.g. Carvedilol has 2 isomers
wherein one isomer [S(-)-
carvedilol] is a potent beta
receptor blocker while the
[R(+)0carvedilol] is 100-fold
weaker at the beta-blocker.
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18
Q

DRUG-BODY INTERACTIONS

A
Pharmacodynamics
 Action (or effect) of the drug to
the body
 Pertains to the Mechanism of
Action
o Pharmacokinetics
 It describes the effect of the body
to the drugs
 Absorption, Distribution,
Metabolism and Excretion
19
Q

agonist receptor

A

o A drug that would activate the receptor
o Ach, when released to the synaptic cleft,
it would bind to the receptor  activate
the receptor

20
Q

antagonist receptor

A

competes with the binding of molecule, atropine ach bound

21
Q

allosteric agonist

A

different site other than the agonist. inhibit agonist

22
Q

allosteric antagonist

A

Different receptor than antagonist

inhibits antagonist

23
Q

To function as a receptor:

A

o An endogenous molecule must first be
selective in choosing a ligand to bind.
o It must also change its function upon
binding.

24
Q

Drugs that mimic agonists inhibit metabolically enzymes

A

o Acetylcholinesterase inhibitor

25
Receptors
o Selective (to avoid constant activation) and changes its function upon binding that the function of the biologic system is altered o Diphenhydramine is highly selective to H1 receptor and Ranitidine highly selective to H2 receptor.
26
inert binding sites
o Binding of the drug to a non-regulatory molecule such as albumin that would result in no detectable change in the function of the biologic system. o Affects the distribution of drug within the body and determines the amount of free drug in circulation.
27
AGONISTS THAT INHIBIT THEIR BINDING MOLECULES
Some drugs mimic agonist drugs by inhibiting molecules responsible for terminating the action of an endogenous agonist.  They do not bind to the receptor however they can prolong the effect of the agonist.
28
Ach as Agonist inhibitor
Acetylcholine. Once it is released in the synaptic cleft, it binds to the receptor and some of the Ach would be then metabolized by your Acetylcholinesterase. If you will inhibit the action of the Acetylcholinesterase by Acetylcholinesterase inhibitor, it can prolong the effect of your Ach in the synapse.
29
agonist mimics are safer, because?
they amplify the effects of physiologically released agonist ligands, their effects are sometimes more selective and less toxic than those of exogenous agonist
30
Full agonist –
activate receptor systems to the | maximum event of which the system is capable.
31
Partial agonist –
bind to the same receptors and activate them in the same way but do not evoke a response, no matter how high the concentration.
32
Inverse agonist –
the drug will reduce constitutive | activity, resulting in effects that are opposite of the effects produced by the conventional agonist at the receptor
33
DURATION OF DRUG ACTION
n some cases, the effect lasts only as long as the drug occupies the receptor, and dissociation of drug from the receptor automatically terminates the effect. In many cases, however, the action may persist after the drug has dissociated because, for example, some coupling molecules are still present in activated form. - In the case of drugs that bind covalently to the receptor site, the effect may persist until the drugreceptor complex is destroyed and new receptors or enzymes are synthesized, for example Aspirin.
34
what is the desensitization mechanism?
Many receptor-effector systems incorporate desensitization mechanisms for preventing excessive activation when agonist molecules continue to be present for long periods.
35
PHARMACOKINETIC priniple
Make a rational dosing possible by quantifying processes such as absorption, distribution, metabolism and elimination.
36
Absorption
``` Route of administration Blood flow  influences absorption from intramuscular and subcutaneous sites and, in shock, from gastrointestinal tract o Concentration  important in determining the concentration gradient relative to the blood. High blood flow maintains high concentration the gradient between the drug depot and the blood and thus facilitates absorption. ```
37
Distribution
``` Determinants of distribution  Size of the organ – concentration gradients  Blood flow – rate of uptake of the drug  Solubility – drug’s concentration in the ECF  Binding – warfarin bound to albumin ```
38
Apparent volume of distribution and | physical volumes
 Relates the amount of drug in the body to the concentration in the plasma
39
Metabolism
``` Drug metabolism as a Mechanism of Activation or Termination of Drug Action  termination of drugs before excretion as they are metabolized to biologically inactive metabolites (eg. Sympathomimetics, phenothiazines) ```
40
lithium is a drug that is eliminated without?
Metabolism
41
most of the drug metabolism in liver occurs by?
Cyt P450 enzyme
42
Elimination
``` o Is not the same as drug excretion o A drug may be eliminated by metabolism long before the modified molecules are excreted from the body o For most drugs and their metabolites, excretion is kidney o Volatile anesthetic gases, a major exception is excreted primarily by the lungs. ```
43
First Order Elimination –
rate of elimination is proportional to the concentration. o Have a characteristic constant half-life.
44
Zero Order Elimination –
rate of elimination is constant regardless of concentration. o Concentration of drugs in plasma decreases in linear fashion over time. o They do not have a constant half-life.