Transcript Introduction to Pharmacology…

Introduction to
Pharmacology…
Learning Objectives

Define the terms Pharmacology, Pharmacokinetics,
Pharmacodynamics.

List the various routes of administration of drugs.

List factor effect on pharmacokinetics.

Describe some factors that dedicate of the dose.
Historical Trends

Since the beginning people search to treat illness and cure disease the oldest
known prescription found on a clay( 5000 years ago).

Primitive people through the Egyptian period believe that evil spirit living in the
body.

Hipocrates ( fifth century) advanced idea that disease resulted from natural
causes.
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The arabs’ interest of in medicine, pharmacy and chimistry was reflected in
hospitals and schools.
Historical Trends
Historical Trends

In twenty first century, the emphasis on
providing quality health care.

Nursing role which include administering
medication in health care agency, community
and home care setting, teaching client safe and
effective self administration to better care for
their clients.
Terminology

Pharmacology: is a science that studies the effect of the
drugs on the body.

Pharmacopeias: are the total of all authorized drugs
available within the country.
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Medication: is a substance administered for diagnosis,
cure, treatment, mitigation or prevention.

Prescription: the written direction for the preparation and
the administration of the drug.
Terminology Cont …..

The therapeutic effect: is the primary effect
intended that is the reason the drug is
prescribed such as morphine sulfate is
analgesia.

Side effect: secondary effect of the drug is one
that unintended, side effects are usually
predictable and may be either harmless
Terminology Cont …..

Drug toxicity: harmful effect of the
drug on an organism or tissue, result
from overdose or external use.

Drug allergy: is immunological
reaction to a drug.
Terminology Cont …..

Drug interaction: occur when
administration of one drug before or
after alter effect of one or both drug.

Drug misuse: Is the improper use of
common medications in way that lead to
acute and chronic toxicity for example
laxative, antacid and vitamins.
Terminology Cont …..

Drug abuse: is an inappropriate intake
of substance either continually or
periodically.

Drug dependence: is a persons reliance
on or need to take drug or substance
there are two type of dependence:
Terminology Cont …..

Physiological dependence: is due to
biochemical changes in the body tissue
these tissue come to require substance
for normal function.

Psychological dependence: is
emotional reliance on a drug to maintain
a since of wellbeing accompanied
feeling of need.
Terminology Cont …..
 Drug
habituation: denotes a mild
form of psychological dependence.
 Illicit
drug: also called street drug
are those sold illegally.
Terminology Cont …..

Dose :The aim to give patient a dose of the
drug that achieves the desired effect with
out causing with harmful side effect.

Therapeutic index: is a measure of the
danger of poisoning and the higher it is
safer of drug is.
Aspirin (3.5), digoxin (2)
Terminology Cont …..

Bioavailability: Means that the drug has
reached the circulation and is therefore
available for all the tissues. (ex: aspirin
600 mg).

Tolerance: A decreasing response to
repetitive drug doses
basic concepts of Pharmacology

Pharmacokinetics: is a bout how the body deal with drug.

Pharmacodynamics: is effect of drug on the body.
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Pharmacotherapeutics: is a clinical using of drug.

Pharmacognosy: The study of natural (plant and animal) drug
sources.
Branches of Pharmacology

Pharmacognosy - Origin

Pharmacokinetics - Movement through Body

Pharmacodynamics - Effect

Pharmacotherapeutics - Use/Purpose

Toxicology -Side Effects
Pharmacokinetics
Science
Pharmacognosy
Toxicology
of Pharmacology
Pharmacodynamics
Pharmacotherapeutics
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The generic name: is given for the drug to being official name.
The official name: is the name under which its listed in one in the
official publication.
The chemical name: is the name by which the chemist knows it.
The trade mark or brand name (proprietary name) : is name given
by the drug manufacture
Example: hydrochlorothiazide (official name).
Esidrex (brand name)
Examples
Chemical
Name
7-chloro-1,3-dihydro1-methyl-5 phenyl
2H-1, 4-benzodiazepin
2-one
Ethyl 1-methyl 4pheyli-sonipecotate
hydrochloride
Generic
Name
diazepam
Trade Name
meperidine
Demerol
acetylsalicyclic aspirin
Valium
Ecotrin
Source of drugs
1.
Plants: such as digitalis, vincristine.
2.
Human and animals: such as
epinphrine, insulin and
adrenocoticotrpoic hormone.
3.
Minirals: as iron, iodine and zinc
4.
Synthetic and chemical substance:
as sodium bicarbonate
Drug Classifications

Pharmacologic Classification
 Similar
Characteristics
 Similar
Chemical Make up
 examples:

Penicillins, Beta Blockers
Therapeutic Classification
 Used
for similar effect
 May
not have similar chemical make up
 Examples: Antihypertensives, Antibiotics
Drug action across lifespan

Drug administration during pregnancy

Drug administration during childhood

Drug administration during adulthood
Drug therapy during Pregnancy and BreastFeeding

Must balance risks vs benefits of drugs during pregnancy
– Affect fetus more than mother?
– Teratogenic effects
– Mother’s health affects fetus—

Chronic asthma is more dangerous to the fetus than the drugs
used for treatment (mother’s who do not take medication for
asthma the incidence of stillbirths is doubled!!)
Drug therapy during Pregnancy and BreastFeeding
 Pregnancy
alters drug disposition and excretion processes

By 3rd trimester renal blood flow is doubled with an increase
in glomerular filtration and elimination of drugs
increases(therefore will need an increased dosage of drug to
compensate)

Tone and motility of intestines (peristalsis) decrease in
pregnancy(more time for drugs to be absorbed)
Drug therapy during Pregnancy and BreastFeeding
All drugs can cross the placenta

Lipid soluble cross more easily

Ionized, highly polar or protein bounds cross with difficulty

Nicotine (smaller babies)

Alcohol (dependence)

Cocaine/heroine/morphine (addictive to fetus)

Bacterial and viral infections
Teratogenesis
 The
process by which congenital
malformations are produced in an
embryo or fetus.
 Cleft
palate
 Hydrocephalus
 Spina
bifida
 Behavioral
and biochemical anomalies
Teratogenesis
3 stages of embryonic development

Pre-implantation (conception to week 20)

Embryogenic period (week 3 to week 8)
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Fetal period (week 9 to term)
– During pre-implantation and embryonic stages the teratogen acts
in an all-or-none response, i.e. , is dose is high enough the fetus will
die, if dose is sub-lethal fetus will recover
– Gross malformations produced by exposure to teratogens during
the embryonic period (1st trimester)
– Exposure during the 2nd and 3rd trimesters usually results in
organ dysfunction rather than gross malformations
Few drugs considered to be teratogenic: hard to prove
– Incidence of congenital anomalies is low
– Animal test may not be applicable
– Prolonged exposure may be necessary
– Teratogenic effects may be delayed
– Behavioral effects are hard to document
– Controlled experiments cannot be done in humans
• To prove a drug is a teratogen:
– Drug must cause a characteristic set of malformations
– It must act only during a specific window of vulnerability
(weeks 4 through 7 of gestation)
– Incidence of malformations should increase with increasing
dosage and duration of exposure
• Risk of malformation with most teratogens is only ~10%
Drug Therapy during Breast Feeding
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Drugs get through breast milk and can affect infant

Lipid soluble drugs are in higher concentration
Things That Can Minimize Risk:
– Dose after breast feeding
– Take drugs with short ½ life
– Take drugs that are not found in breast milk
– Avoid drugs known to be hazardous
Drug Therapy in Pediatric Patients
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Patients who are young or old respond differently to drugs than do
middle aged people
Pediatrics- all patients under age 16
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Pre-mature infants (< 36 weeks gestation)
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Full-term infants (36-40 weeks gestational age)
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Neonates (1st 4 weeks post-natal)
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Infants (5-32 weeks postnatal)
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Children (1-12 years)
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Adolescents (12-16 years)
Very Young Patients
– At risk for prolonged and intense responses
Response of Infants due to differences in:
• Drug absorption- absorption of drugs IM is greater in infants
than neonates and adults
• Renal drug excretion (reduced in infants)
• Hepatic drug metabolism (low in new born)
• Protein binding of drugs (albumin lower in infants)
• Exclusion of drugs from CNS by blood-brain barrier (not sully
developed in infancy making infant much more susceptible to
drugs)
– By one year- pharmacokinetic response similar to adult
Drug Therapy in Geriatric Patients
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Elderly more sensitive to drugs and exhibit more variability in
response
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Altered pharmacokinetics (organ degeneration)

Multiple and severe illnesses
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Multiple drug therapy and usage
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Poor compliance
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“Individualization of treatment is essential: each patient must
be monitored for desired responses and adverse responses, and
the regime must be adjusted accordingly”
Geriatric patients will vary quite a lot from one patient to another
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Physically fit patients respond differently than out of shape
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Absorption- percentage of absorption DOES NOT usually change with
age, but rate may be slowed (drug response may be delayed)

Gastric acidity may be increased in aged affecting absorption of certain
drugs

Distribution- in aged there is:
 Increased body fat-
reduces plasma levels of lipid soluble drugs
 Decreased total
body water- increases concentration of water soluble
drugs and intensity of response
 Reduced
concentration of serum albumin- malnourishment decreases
albumin and results in increased drug levels
Metabolism:
hepatic functions decrease in elderly and drug levels increase
(amount of dysfunction variable)
Excretion: decline of renal function in elderly (variable) therefore
increase drug levels in plasma

Determine renal function by creatinine clearance rates
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Pharmacodynamic Changes: alterations in receptor levels may
change on a number of cells.
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Decreased affinity of receptors
Route of administration:
1.
Oral is the most common
Advantage:

Least expensive and most convenient route for most
clients.

Safe, does not break the skin.

Concoius, able to swallow.
Oral medication
Oral Route
Disadvantage:
 Inappropriate for client nausea and
vomiting.
 Drug may have unpleasant taste.
 May cause irritation of gastro intestinal
tract.
 Drug may discolor teeth.
 Drug can be aspirated by ill client.
Sublingual
A drug placed under the tongue, where it
dissolved.
Advantage:
 Same as oral plus
 Drug may administered for local effect.


Drug rapidly absorbed into blood stream.
More potent than oral.
Disadvantage:
 If swallowed drug may be inactive.
 Drug must remain under the tongue until
dissolved.
3. Baccal: pertaining to the cheeks.
4 . Rectal: can be used when drug objectionable
taste.
5. Translingual: on the tongue.
5. Subcutaneous (SC): hypodermic into subcutaneous
tissue, just below the skin.
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
Advantage: onset drug action faster than oral.
Disadvantage: SC
1.
2.
3.
4.
5.
Must involve sterile technique because breaks
skin barrier.
More expensive than oral.
Can administer only small doses.
Slower than intramuscular injection.
Some drug can irritate tissue and can cause
pain.
6.Intramuscular (IM): into in the muscle.
Advantage:
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Pain from irritating drugs is minimized.
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Can administer large volume of drug.
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Drug rapidly absorbed.
Disadvantage:
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breaks skin barrier.
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Can be anxiety producing.
7. Intradermal (ID): is the administrating of a
drug into the dermal layer of the skin just
beneath the epidermis, usually small amount of
liquid is used for example 0.1ml.

Advantage: absorption is slow (this advantage
test for allergy).

Disadvantage:

amount of drug administered must be small.
 Breaks
skin barrier
8. Intravenous (IV): allow injection of drugs and another
substance directly into bloodstream through the vein.
9. Inhalation: is apply to drugs directly onto lungs.
10. Topical Route
1.
Skin (including transdermal patches)
4.
Eyes
Ears
Nose
5.
Lungs (inhalation)
2.
3.
Question?