NR 508 PHARM MIDTERM STUDY GUIDE / NR508 PHARM MIDTERM STUDY GUIDE: LATEST,CHAMBERLAIN COLLEGE OF NURSING
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Course
NR 508 (NR508)
Institution
:CHAMBERLAIN COLLEGE OF NURSING
NR 508 PHARM MIDTERM STUDY GUIDE / NR508 PHARM MIDTERM STUDY GUIDE: LATEST,CHAMBERLAIN COLLEGE OF NURSINGNR 508 PHARM MIDTERM STUDY GUIDE / NR508 PHARM MIDTERM STUDY GUIDE: LATEST,CHAMBERLAIN COLLEGE OF NURSINGNR 508 PHARM MIDTERM STUDY GUIDE / NR508 PHARM MIDTERM STUDY GUIDE: LATEST,CHAMBERLAIN CO...
NR 508 PHARM MIDTERM STUDY GUIDE
CHAPTER-1 TO CHAPTER- 36(ALL CHAPTER
INCLUDED)
Chapter 2: Review of Basic Principles of Pharmacology
Metabolism: Metabolism & Half Life
● Metabolism can increase, decrease onset duration of action, and toxicity of
medications
● Change one chemical into another
● First pass metabolism: liver major organ for drug metabolism because it
contains high amounts of drug metabolism enzymes and because it is the
first organ encountered by the drug once they are absorbed by the GI tract.
Determines if can be given orally.
● Rate of drug metabolism depends on drug blood level and the affinity of the
drug to be metabolize by the metabolizing enzyme.
● The metabolism of the drug is related to the concentration of the drug. A
fixed fraction of the drug is metabolized per hour. First order metabolism is
time drug decreases by half (half-life). In other words, when the drug
reaches half of the concentration, then we can call it first order metabolism
● 50% at one half-life 75 at two half-lives and 87.5 at three half lives
Drug Responses
● Before a medication can produce a response, it often must overcome
homeostatic mechanisms.
● Homeostasis is when the cell or tissue does NOT respond to the drug and
instead maintains the environment by keep doing what it knows best, fix
itself.
● Pharmacology is the study of substances that produce biological responses,
measurement of what happens when we administer medications is important.
Receptors: agonists, antagonists
, 1
● Agonists: drugs that produce receptor stimulation and change what they
bind
o Agonist is a chemic that binds to a receptor and activates the receptor
to produce a biological response.
o Agonist causes an action in the body; The Antagonist blocks the
action of the agonist. By occupying the receptor
o Agonists- you tell the body what to do
o Antagonist- you tell the body what not to do by blocking the receptor
thus blocking biological response
● Antagonist: occupy receptor without stimulating them prevent agonist from
occupying them.
o Provides no direct response. The response we see following
administrating of antagonist results from inhibiting receptor
stimulation by agonist. For example: BB propanol and atenolol.
o The effect of an antagonist is dependent on its blood levels and its
affinity for the receptor.
o it is possible to overcome the antagonist effects with higher
concentrations of the competing agonist
Pharmacokinetics: Absorption, Distribution, Protein Binding, Metabolism
(including first-pass and Phase I and II)
● Absorption
o By weight solubility, and other factors
o GI like foods change absorption
o The route of administration also affects patient compliance
o Enteric-coated formulations protect the medication in the stomach and
only disintegrate and dissolve when they reach the gentler conditions
of the intestinal tract
o Only a fraction of the drug administered makes it to the blood stream,
it must go through the liver first. This fraction of drug that enters the
blood stream is called bioavailability. First pass
, 2
● Distribution
o The process of drugs moving throughout the body is called
distribution and it happens after the drug reaches the site of action
o Distribution can occur by transfer, passive diffusion or the drug
distribution can be changed by transport systems that may pick to
transport or exclude dugs based on
▪ Size, charge or structure.
o Diffusion can influence distribution.
o Drugs can be distributed faster if they are small, uncharged and have
a good balance between water and lipid solubility. Passive diffusion-
permeable barriers, smaller molecules get to distributed better
● Plasma protein binding
o If not, protein bound; its higher in blood and tissues
o Drugs passively diffuse and distribute when they are unbound and
uncharged.
o Plasma proteins- is when drugs bind to protein in the bloodstream.
They are produced in the liver and their presence in the bloodstream
affect liver function, nutritional status and disease. For example:
Albumin.
o Other plasma proteins include alpha-1-acid glycoprotein, cortisol-
binding globulin, sex hormone–binding globulin, and lipoproteins.
o Drugs bound to plasma proteins can freely circulate in the
bloodstream rather than be distributed by passive diffusion from their
site of absorption, so plasma protein binding helps normalize
concentrations throughout the body.
o Drugs bound to protein are protected from metabolism in the liver and
from excretion by the kidneys. They stay longer in the body actively.
o Protein can extend the period of time that drugs remain in the body;
this is very important.
, 3
o If a patient does not have the proper nutrition state, or disease that
alters protein in the body, may not be up to par.
▪ For example: cancer patients, liver disease, MI, stress and
infection
o Advantages: Protein can protect drugs from metabolism and
excretion; extending the time of the drug in the body
o Disadvantage: the general principle that drug action occurs through
free, unbound drug. Protein binding also prevents the interaction of
drug at the site of action.
▪ Plasma protein hold drugs in the circulation and prevents their
distribution to other sites in the body. Example: Digibind
▪ Drugs bound to plasma proteins cannot interact with their
receptor. Example Warfarin, 98% is bound to plasma protein,
and only 2% is free and unbound to produce an effect.
o Storage
▪ Lipoic accumulate in fats, calcium in teeth
● Metabolism
o Metabolism is important in drug activity. Drugs when metabolized
turn into metabolites
o Drugs that are lipid soluble or weakly acidic or basic may not readily
be excreted from the body. It has to be water solubility to be excreted
by the kidneys.
o Metabolism is the process of changing one chemical into another, and
the process usually either creates or uses energy.
o Metabolism occurs mostly in the smooth endoplasmic reticulum of
cells in the liver
o Metabolism by the liver following oral administration is called first-
pass metabolism and is important in determining whether a drug can
be orally administered.
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