PHARMACOLOGY
Author: Gia Phong Vu, MD. PhD.
Lecturers: Dung Tran Trung Msc.
Nguyen Vo Khoi Msc.
Learning Outcomes:
1
List and define the major
areas of pharmacology.
2
3
4
Describe what a drug is
and explain the differences
between therapeutic
effect, side effect, and
toxic effect.
Understand the terms site
of action and mechanism
of action, and how agonist
and antagonist drugs
interact at drug receptor
sites.
Characterize the
relationship between drug
dosage and drug response,
and the relationship
between drug response
time
Learning Outcomes cont.
5
1
62
73
48
Explain the
nomenclature used
to name and classify
drug
Understand the
term associate with
drug safety
Explain the
nomenclature used
to name and classify
drug
Recall the main drug
references and the
information they
provide.
Drug Sources
Early days:
v Plants
• Morphine and Codein from poppy
plant (Papver somniferum)
• Digitalis from Foxglove
• Antimalaria quinine (cinchona tree)
• Paclitaxel, anticancer from yew tree)
v Animals
• Insulin from pigs (in the early date)
• Growth hormone
v Micro-organism
• Early antibiotics from fungi such as
Penicillium
v Minerals
Drug Sources
Modern day:
vChemical Synthetic and Semi-synthetic
vProducts of modern medicine:
o Molecular Biology
o Gene therapy
o New types of drugs such as monoclonal antibodies
Major Areas of Pharmacology
Area
Description
Pharmacodynamics
Study of the action of drugs on living tissue
Pharmacokinetics
Study of the processes of drug absorption, distribution, metabolism, and excretion
Pharmacotherapeutics
Study of the use of drugs in treating disease
Posology
Study of the amount of drug that is required to produce therapeutic effects
Toxicology
Study of the harmful effects of drugs on living tissues
Terminology Related to Drug Effects
Major Areas of Pharmacology:
• Pure drug: a chemical compound with a specific chemical structure.
o Chemical properties
o Biological properties
• Therapeutic effect:
o The intended effect of the drug
• Drug indication:
o Therapeutics use(s) of the drug – indications for use
• Contra-indication: situation or circumstances when the drug SHOULD NOT be used.
Terminology Related to Drug Effects
cont.
Side Effects:
Adverse Effects:
• Minor nuisance or
annoyance caused by the
drug
• Cost vs. benefit
• Harmful effects
• Prolonged treatment may
effects the function of
vital organ such as liver or
kidney
Toxic Effects (Toxicity)
• Drug poisoining, the
consequences of which
can be harmful and may
be life-threatening
• The drug must be
stopped, antidotes and
supportive treatment
should be given next.
Basic Concepts in Pharmacology
• Site of Action:
o Location within the body where the drug exerts
its therapeutics effects
• Mechanism of action:
o Explain how a drug produces its effects
• Receptor site:
o Chemical structure located on the cell membrane
or within the cell where drug(s) attached.
• Agonists:
o Drug that binds to a specific receptors and
produce a drug action
Basic Concepts in
Pharmacology
• Antagonists:
o Drugs that binds to specific receptors and block agonist
drug action or cellular function
o Also known as blocking drugs– prevent body
substances to bind
§ Example: Naloxone – morphine antagonize – treat
morphine overdose
o Competitive antagonism – agonist and antagonist
compete administered together and compete for the
same receptor site.
Dose-Response Curve
• A dose is the exact amount of a drug
that is administered to produce a
specific effect, a response.
•
•
Drug response is proportional to the
dose
Maximal response (100% magnitude)increase in dose do not yield any greater
effect – Ceiling effect.
• Potency is a measure of the
strength, or concentration, of a
drug required to produce a
specific effect.
•
The dose that will produce an effect that
is half of the maximal response is
referred to as the effective dose 50, or
ED50
Time-Plasma Drug
Concentration Curve
• Duration of action is the length of time
that a drug continues to produce its
effect.
• The time from drug administration to
the first observable effect is known as
the onset of action.
• When the plasma drug concentration
falls below the therapeutic range,
there is termination of drug action.
DRUG SAFETY
• 2 major requirements for drugs to before it
can be approved for used in humans:
1)
Efficacy
2)
Safety
DRUG SAFETY (cont.)
• LD50 – lethal dose 50 – the dose that kill 50% of
the animals tested
• Therapeutic Index (TI) is the ratio of LD50 to the
ED50 of a drug
• TI = LD50/ED50
Adverse Drug Effects (A.D.E.)
• Adverse effects are dose dependent
• Few adverse effects are not dose dependent such as idiosyncrasy and drug
allergy – determined by individual variation
Frequently affected tissues
• Oral drugs often cause nausea, vomiting, diarrhea because of GI
irritation.
• Liver, kidneys, brain, vascular system are organs exposed to highest
concentration of drugs
• Birth defect drugs known as teratogens
• Tumor promoting drugs known as carcinogens
A.D.E. Cont.
• Drug allergy occurs when an individual becomes sensitized to a
particular drug
• an individual may develop antibodies into a particular drug
• Antigens and antibodies reactions involving drugs usually cause the
release of histamine and order inflammatory mediators from cells
known as mass cells.
• Symptom involve, including crashes, hives, itching, nasal secretions,
hypotension, bronchoconstriction.
• The term anaphylaxis is used to describe serious allergic reactions.
1.6. Drug
Nomenclature
• Long chemical name à shorter
nonpropietary (non trademark)
name which is commonly a
contraction of the chemical name
commonly referred as generic
name
• Propietary name also known as
trade name or brand name.
1.6. Drug Nomenclature
Prescription drugs require a written or
phone order (the prescription), which can only be
issued
by or under the direction of a licensed physician,
dentist,
or veterinarian.
• Nonprescription
drugs, usually referred to as “over-the-counter” (OTC)
drugs (such as aspirin, antacids, cold remedies), can be
purchased anywhere and do not require the services of
a
physician or pharmacist.
•
Lesson Review
1. The study of drug absorption, distribution, metabolism, and excretion is known as (LO 1.1)
A. pharmacotherapeutics
B. pharmacodynamics
C. pharmacokinetics
D. pharmacy
E. posology
2. The medical situation when a particular drug should not be administered is referred to as (LO 1.2)
A. side effect
B. adverse effect
C. drug allergy
D. contraindication
E. antagonism
Lesson Review
3. An unusual or unexpected drug reaction by an individual is known as (LO 1.5)
A. toxic effect
B. antagonism
C. idiosyncrasy
D. side effect
E. drug allergy
4. The proprietary drug name supplied by a pharmaceutical company is also referred to as the (LO 1.6)
A. generic name
B. over-the-counter name
C. trade name
D. chemical name
E. none of these
5. The time from drug administration to the first observable drug effect is known as the (LO 1.4)
A. duration of action
B. onset of action
C. ceiling effect
D. maximal response
E. ceiling effect
Lesson Review
6. A drug that has the potential for abuse and is regulated by the Drug Enforcement Agency is classified
as a
A. poison
B. OTC drug
C. prescription drug
D. controlled substance
E. nonproprietary drug
7. Select the term that relates to the amount of drug administered to produce a therapeutic
effect. (
A. posology
B. toxicology
C. pharmacodynamics
D. pharmacotherapeutics
E. pharmacy
Lesson Review
8. A medication that does not require a physician’s service to obtain is referred to as (LO 1.6)
A. trade
B. nonproprietary
C. nonprescription
D. brand
E. generic
9. Which of the following could be categorized as an adverse reaction? (LO 1.5)
A. idiosyncrasy
B. drug allergy
C. teratogenicity
D. carcinogenicity
E. all of these
10. The time a drug continues to produce its effect is its (LO 1.4)
A. ED50
B. maximal response
C. ceiling effect
D. onset of action
E. duration of action