Introduction to pharmacology basic pharmacology by Saeed Anwar

1. INTRODUCTION
TO
PHARMACOLOGY
BS Nursing
3rd Semester
Dr Saeed Anwar
Lecturer Pharmacology
Swat College of Nursing Swat
. UNIT 1

2. Pharmacology
Pharmacology is derived from a Greek
word.“Pharmacon” means (drug), and logy
means (To study)
Pharmacology is a branch of science that
deals with the interaction of drugs with living
organisms, is called Pharmacology
OR
The study of Pharmacokinetics and
Pharmacodynamics.

3. What is a drug?

4. Drug
Any chemical or natural substances used in
investigation, diagnosis, treatment and
management of different diseases in humans
and animals is called drug. May have a
Positive or Negative effect
Paracetamol, Ibuprofen Heroin,etc

5. Medicine
Medicine is a substance used therapeutically only to treat
disease, only positive effects is giving.
e.g Paracetamol, asprin etc
All medicines are drugs but
all drugs are not medicines.

6. Branches of
Pharmacology
1. Pharmacokinetics
2. Pharmacodynamics
3. Pharmacotherapeutics
4. Clinical pharmacology
5.Toxicology

7. Branches of Pharmacology
Main two branches
1. Pharmacokinetics (PK)
2. Pharmacodynamics (Pd)

8. Pharmacokinetics
Deals with the study of ADME process
A= Absorption
D=Distribution
M=Metabolism
E=Excretion
In this we study absorption, distribution, metabolism &
excretion of a drug.
OR
what the body does to the drug

9. Pharmacokinetics

10. Pharmacodynamics
Deals with the study of Mechanism of
action and Mode of action of a drug
OR
What the drug does to the body

11. Pharmacotherapeutics:
Clinical application of pharmacodynamics and
pharmacokinetics information to cure a disease
.
Clinical pharmacology:
Deals with the comparative clinical evaluations
of new drug for developing its therapeutic
efficacy and safety
Toxicology:
Deals with the toxicity and poisonous effects of
various chemicals and also with the symptoms
and treatment of poisoning

12. Dose………….
Dosage……….
Dosage form....

13. Dose
A Specific Amount of Drug Prescribed to be
taken at one time.
Dosage
The determination and regulation of the size,
frequency and number of doses.
Dosage form
Any pharmaceutical product which has defined
shape and have prescribed amount of active
ingredient is called a dosage form. E.g tablet,
capsules, injection, syrup, cream and ointment
etc

14. CLASSIFICATION OF DRUGS
1. On The Basis Of Sale
2. On The Basis Of Their Sources

15. On The Basis Of Sale
.
OTC
Over The
Counter Drug
POM
Prescription
Only Medicines

16. OTC
OTC (over the counter) is the
group of drug that does not
required any prescription for
their dispensing. This group
contains the following drugs
 Multi vitamin
 NSAIDS (non steroidal
anti inflammatory drugs)
 Laxatives
 Some Nutraceuticals
 Oral contraceptics
Prescription only
medicines
Those medicine or drugs
which must not dispense
without prescription. This
group contain following
drugs.
 Antibiotics
 Steroids
 Benzodiazepines
 Barbiturates
 Anti diabetics
 Anti hypertension
 Anti viral etc

17. CLASSIFICATION OF DRUGS
.
Synthetic
source
Natural
source
Semi synthetic
source

18. NATURAL SOURCES
Animal sources Plant sources Microbial sources

19. 1. Plant sources
These are drugs which obtained from different parts of
plant(root, bark, stem, leaves, seeds and flower
 Strychnine from Nux vomica
 Reserpine is obtained from Rauwolfia serpentina
 Cinnamon aldehydes obtained from cinnamon
 Quinine from cinchona plant
 Digoxin is obtained from Digitalis lanata
Other Plant sources using for drugs like Curcuma longa,
Rumex acetos, Rumex hastatus, Rumex crispus, R vesicaris etc

20. 2. Animal Sources
Many animals are involved in the production of many important drugs
 Vaccines
 Insulin
 Sex hormones
 Thyroxin
3. Microbial Sources
This is the group of medicines/drugs that are synthesized by using different micro organisms; this
group includes the following drugs
 Antibiotics
 Insulin
 Vaccines

21. SEMI SYNTHETIC DRUGS
Semi synthetic drugs are the group of drugs/medicines
that are synthesized by using combined of natural
sources and synthetic sources.Examples are
 Amoxicillin (Penicillium fungi)
 Cefixime (Marine fungus)
 Ceftriaxzone

22. SYNTHETIC DRUGS
Synthetic drugs are the group of drugs/medicines that are totally
synthesized in laboratory by using chemicals.
Examples are…..
 Paracetamol
 Aspirin
 Ciprofloxacin
 Sulfonamide group e.g septran
Sulfamethoxazole/trimethoprim

23. Drug Nomenclature
Drug names
1. Brand Name
2. Generic Name
3. Chemical Name
Brand Name
Generic Name
Chemical Name

24. It is defined as a fraction of drug reached to the
systemic circulation after it is administered by any
route.
IV administration of drug produces 100%
bioavailability as a whole of the drug enters the
systemic circulation. Oral administration of the drug
may not produce 100% bioavailability due to
incomplete absorption of a drug from the
Gastrointestinal tract and due to first pass effects of
some of the drugs.
Bioavailability

25. Factors affecting bioavailability
1. Route of drug administration
2. Solubility
3. First pass effect
4. Chemically instability
-----------------------------------
If 100mg drug taken orally, 70mg is
absorbed into blood in unchanged form, the
bioavailability is 70%.

26. Pro drug
It is an inactive drug which become active when
metabolized in the body. e.g. Methyl dopa,
sulfasalazine
OR
A drug substance that needs to be converted into the
pharmacologically active agent by metabolic or
physicochemical transformation.
Placebo
A placebo is made to look exactly like a real drug but
is made of an inactive substance, such as a starch.
A substance that has no therapeutic effect, used as a
control in testing new drugs.
Placebos are now used only in research studies

27. Side Effect
A side effect is „any unintended effect
of a pharmaceutical product occurring
at doses normally used by a patient
which is related to the pharmacological
properties of the drug‟.
It is undesirable but it could be
beneficial (e.g. an anxiolytic effect
from a beta-blocker prescribed for
hypertension).
Minoxidil is antihypertensive use to
treat baldness as SE
Adverse Drug Reaction
A response to a drug which is noxious and
unintended, and which occurs at doses
normally used in man for the prophylaxis,
diagnosis, or therapy of disease, or for the
modifications of physiological function.
.
Undesired
effects

28. Side Effect Adverse Drug Reaction
 Generally expected
 Good or Bad
 Sef resolving
 Examples nausea,
vomiting, dry mouth etc
 Generally unexpected
 Bad
 Noxious in nature
(Thalidomide)
 Serious in nature
 Death, disability, heart
attack

29. An antidote is an therapeutic substance used to counteract the
toxic action(s) of a specified drug or poison.
For example
 Acetylcysteine for paracetamol poisoning
 Activated charcoal for most poisons
 Atropine for organophosphates and carbamates
 Dimercaprol for arsenic, gold, or inorganic mercury
poisoning
 Flumazenil for benzodiazepine overdose
 Naloxone for opioid overdose
Antidote

30. Repeated use of a drug causes a gradual decrease in the
response to the drug.e.g chronic use of morphine and heroin
will decrease many of its effects in the body, therefore the
dose of the drug has to be increased with the passage of time
to maintain the usual effects of the drug.
 Patient requires increased doses to produce effects seen at earlier times
 Increased dose produces increased levels of drug in blood over
Tolerance

31. The ratio between toxic dose (TD50) and
effective dose (ED50) is called therapeutic
index.
Therapeutic index= TD50/ED50
Therapeutic index

32. It is defined as the hepatic metabolism of a drug
when it is absorbed from the gut and delivered to
the liver via the portal circulation. The greater the
first-pass effect, the less the agent will reach the
systemic circulation when the agent is
administered orally.
First-pass Effect

33. It is time required to change the amount of drug in the body by one
half(50%) during elimination (excretion or metabolism). Denoted by t½.
OR
In other words, after one half-life, the concentration of the drug in the body
will be half of the starting dose.
OR
The half-life of a drug is the period of time required for its concentration or
amount in the body to be reduced by exactly one-half.
For example Drug A has a half-life of 2 hours. If the initial plasma level of
the drug, given as a single dose, is 1200mg/L, what will its plasma level be
after 8 hours?
Method
2hr-----1 half life -----1200mg/L-----600mg/L
4hr-----2half life -----600mg/L-----300mg/L
6hr-----3 half life -----300mg/L-----150mg/L
8hr-----4 half life -----150mg/L-----75mg/L
Half Life

34. Posology
A branch of pharmacology which deals
with dose or quantity of drugs which can
be administered to a patient to get the
desired pharmacological action.

35. Hypersensitivity
An allergic or immunological response to a drug .
For example anaphylactic shock with penicillin is a
severe type of hypersensitivity reaction.
Idiosyncrasy
It is a rare type of response to a drug that is not
related to its dose, that is, even a small dose can cause
it.
For example A rare adverse effect with
chloramphenicol is aplastic anemia.

36. Application of Pharmacology in Nursing Practice
Nurse‟s “Five Rights of Drug Administration”
Use the RIGHT drug
Give to the RIGHT patient
Give the RIGHT dose
Give by the RIGHT route
Give at the RIGHT time
Must also be ready to respond to interaction between
drug and patient (must be aware of adverse drug
reactions and side effects)
Rational use of drugs

37. Physical Dependence
Long-term use of drug may lead to dependence (opioids, alcohol,barbituates,
amphetamines)
Body adapts to drug so that if drug discontinued then withdrawl syndrome
will develop.
Teratogenic Effect
 Drug induced birth defect
Carcinogenic Effect
 Certain medications lead to cancer

38. Thanks