Introduction to
pharmacology
By Satarkulova A.M.
Pharmacology
Pharmacology is the science of drugs, including
their ingredients, preparation, uses, and actions on
the body.
Clinical pharmacology is the study of drugs in
human patients
Toxicology is the study of harmful rather than
therapeutic effects
Pharmacy involves manufacture, preparation,
and dispensing of drugs
Drug:
A substance that is used in the prevention, diagnosis, or
treatment of disease
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What is Pharmacology ?
Pharmacokinetics Pharmacodynamics
What the body does to drug What the drug does to body
Pharmacology
Pharmacotherapeutics Pharmacocognosy
The study of the use of drugs Identifying crude materials as drugs
Toxicology
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PHARMACOKINETICS
ABSORBTION,
DISTRIBUTION,
METABOLISM (BIOTRANSFORMATION)
AND EXCRETION OF DRUGS
WHAT THE ORGANISM DOES TO THE DRUGS
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PHARMACODYNAMICS
BIOCEMICAL AND PHYSIOLOGICAL EFFECTS OF
DRUGS AND THEIR MODE OF ACTION
IT INCLUDES:
THE DOSE-EFFECT RELATIONSHIP,
FACTORS MODIFYING DRUG EFFECTS,
DOSAGE,
DRUG TOXICITY
WHAT DRUGS DO TO THE ORGANISM
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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
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Drug Nomenclature
Drugs are identified by one of three names:
Chemical name: -long name, describes the chemical
constituents of the drug.
e.g B-(3, 4 dihydroxyphenyl) -a-methylaminoethanol
Generic name: - Original chemical name of drug assigned
by the manufacturer that first develops it.
e.g epinephrine
Trade name: - brand name given by the company that
sells the drug e.g EpiPen
One drug may have more than one trade name
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Nadolol
( 1, 2 - adrenoblocker )
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Becotide = Beclometh
(beclomethasone dipropionate)
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Routes of drug administration
Enteral
Parenteral
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Enteral Routes
Enteral - drug placed directly in the
gastrointestinal tract (G.I.T):
1. Sublingual - placed under the tongue
2. Oral - swallowed (p.o.)
3. Rectum - Absorption through the
rectum
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1- Sublingual/Buccal
Advantages:
1. Rapid absorption
2. Drug stability
3. Avoid first-pass effect
Disadvantages:
1. inconvenient
2. small doses
3. unpleasant taste of some drugs
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2- Oral
Advantages
1. Convenient - can be self- administered, pain
free, easy to take
2. Absorption - takes place along the whole
length of the GI tract
3. Cheap - compared to most other parenteral
routes
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2- Oral
Disadvantages
1. Sometimes inefficient - only part of the drug may
be absorbed
2. First-pass effect - drugs absorbed orally are
initially transported to the liver via the portal
vein
3. Irritation to gastric mucosa - nausea and vomiting
4. Destruction of drugs by gastric acid and digestive
juices
5. Effect too slow for emergencies
6. Unpleasant taste of some drugs
7. Unable to use in unconscious patient
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3- Rectal
Advantages
1. Used in unconscious patients and children
2. If patient is nauseous or vomiting
3. Good for drugs affecting the bowel such
as laxatives
Disadvantages
1. Irritating drugs contraindicated
2. Absorption may be variable
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Parenteral Routes
1. Intravascular (I.V{intravenous}, I.A{intra-arterial} )-
placing a drug directly into the blood stream
2. Intramuscular (I.M) - drug injected into skeletal
muscle
3. Subcutaneous (S.C)- Absorption of drugs from the
subcutaneous tissues
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1- Intravascular
Advantages
1. First pass metabolism is bypassed
(100% bioavailability)
2.Precise, accurate and almost immediate onset of
action
3. Large quantities can be given, pain free
Disadvantages
1. Greater risk of adverse effects
a. high concentration attained rapidly
b. risk of embolism
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2-Intramuscular
Advantages:
Very rapid absorption of drugs in aqueous
solution
Disadvantages:
Pain at injection sites for certain drugs
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3-Subcutaneous
Advantages:
1. Slow and constant absorption
2. Absorption is limited by blood flow,
affected if circulatory problems exist
3. Concurrent administration of
vasoconstrictor will slow absorption
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Inhalation
Advantages
1.Gaseous and volatile agents and aerosols
2.Rapid onset of action due to rapid access to circulation
a. Large surface area
b. Thin membranes separates alveoli from circulation
c. High blood flow
Disadvantages
1. Needs special apparatus
2. Drugs may be irritants to the mucus membrane
3. For local effect in the bronchi, the bronchial tree should not
be obstructed with mucous plugs as in case of asthma
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Prescribed Inhaler
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Topical
1. Mucosal membranes (eye drops, antiseptic)
2. Skin
a. Dermal - rubbing in of oil or ointment
(local action)
b. Transdermal - absorption of drug through
skin (systemic action)
Advantages:
i. Stable blood levels
ii. No first pass metabolism
Disadvantages:
iii. drug must be potent or patch
becomes to large
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Routes of Drug Administration and
skin
Absorption
Contact or
Transdermal:
1 to 2 days
Copyright, 2004, CNS Productions, 7
Inc.
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Route of administration
Is determined by :
1. The physical characteristics of the drug,
2. The speed which the drug is absorbed and/ or released,
3. The need to bypass hepatic metabolism and achieve high
conc. at particular sites
NB:
No single route of drug administration is ideal
for all drugs in all circumstances
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DOSAGE FORMS OF
DRUG
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Classification of pharmaceutical dosage forms
according to its physical properties
1. Gaseous dosage forms
2. Liquid dosage forms
3. Semisolid dosage forms
4. Solid dosage forms
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Classification of pharmaceutical dosage forms
according to its physical properties
1- Gases
Medicinal gases, inhalation/volatile anaesthetics
Aerodispersions of solid particles (e.g., inhalation antiasthmatics) or liquid
particles (inhalation antiasthmatics or sprays)
2- Liquids
Solutions prepared by dissolving one or more solutes in a solvent
Emulsions
consisting of two immiscible liquids
o/w or w/o
cloudy appearance
Suspensions
Solid particles are dispersed in liquid
Not intended for systemic administration of drugs with high potency
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Gases
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Suspensions
Nitroglycerin Tablets or Spray
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Classification of pharmaceutical dosage forms
according to its physical properties
3- Semisolid dosage forms
Unshaped (without specific physical shape)
Gels
Creams
Ointments
Shaped
Suppositories
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Gels or Paste
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Classification of pharmaceutical dosage forms
according to its physical properties
4. Solid dosage forms
Unshaped
- powders
Shaped
- Tablets
- Capsules
- Transdermal patches
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Dosage Forms For
Systemic
Administration
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Dosage forms for systemic administration
ORAL (p.o.)
1- solid dosage forms
1- solid
Pills
Capsules
Tablets
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Dosage forms for systemic administration
ORAL (p.o.)
solid dosage forms
Tablets :
1- Coated
- To mask unpleasant taste or smell
- To avoid of adhesion in oesophagus (to facilitate swallowing
and/or avoid local adverse reactions)
- To ensure drug stability
2- Effervescent tablets
Not a final dosage form (drug is administered as
the solution)
- Rapid absorption rapid on-set of action
- Avoids potential tablet adhesion to mucosa and
local irritation
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Dosage forms for systemic administration
ORAL (p.o.)
2- Liquid dosage forms
Solutions (drops) aqueous, oils
Syrups aqueous sol. with sugar
(or sugar substitute) with/without
flavouring agents
Emulsions
Suspension
Advantages: easier for administration
(children, elderly people), good
compliance (can be flavoured), rapid
absorption, flexible dosing
Disadvantages: stability (chemical,
microbial - a need for preservatives),
accurate dosing??
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Dosage Forms For Systemic Administration
Parenteral Route
Dosage Forms
Injections (available as
ampoules, vials with rubber
head)
Solutions, emulsions or
suspensions which MUST BE
- STERILE
- PYROGEN-FREE
- ISOTONIC
1- lntravenous ( I.V.)
injections
2- intramuscular (I.M.) and
subcutaneous ( S.C.)
3- Infusions
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Sample Documentation
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Sample Question
A client is nauseated, has been vomiting for
several hours, and needs to receive an
antinausea medication. The nurse
recognizes that which of the following is
accurate?
A. An enteric-coated medication should be
given.
B. Medication will not be absorbed as easily
because of the nausea.
C. A parental route is the route of choice.
D. A rectal suppository must be administered
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Sample Question
Patient . admitted in the hospital in
unconsciousness with the diagnosis
of acute cardiac insufficiency. The
doctor has administered cardiotonic
agent. What route of drug
administration is suitable in this
case?
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