Pharmacology is the science of drugs, including their names, effects on the body, and clinical uses. It has two main divisions: pharmacokinetics, which studies what the body does to drugs, and pharmacodynamics, which studies what drugs do to the body. Drugs come from natural sources like plants, animals and microbes, or they can be synthesized chemically. A prescription provides instructions from a healthcare provider to a pharmacist regarding a specific medication for a particular patient, including the name, dose, directions, and other important information. Prescriptions must follow standard formats and include additional details for controlled substances due to their potential for abuse.

1. General Pharmacology
Introduction to Pharmacology
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2. Definitions
Pharmacology
– Pharmakon : drug
– Logos: Science
• Is the science that deals with the drugs names,
pharmacokinetics, pharmacodynamics, side effects
and clinical uses.
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3. Main Divisions
• Pharmacology is mainly divided into two parts:
1. Pharmacokinetics
What the body does to the drug?
2. Pharmacodynamics
What the drug does to the body?
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4. 4

5. Pharmacology:
Pharmacokinetics
• Are studies of the
– Absorption
– Distribution
– Metabolism
– Excretion
Pharmacodynamics
• Are studies of
- Mechanisms of drug action (MOA)
- Pharmacological effects (therapeutic effects & toxic effects)
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6. Other subdivisions of Pharmacology …
• Pharmacogenomics: The study of genetic influences on
the effectiveness and fate of drugs
• Toxicology: the study of the adverse or toxic effects of
drugs and other chemical agents
• Therapeutics: Medical treatment of disease
• Pharmacoeconomics: compares the value of one
pharmaceutical drug or drug therapy to another
• Pharmacoepidemiology: is the study of the use and the
effects of drugs in large numbers of people
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7. What is a drug?
• A drug is any chemical substance that modify
physiological system or pathological state and can
be used for diagnosis, prevention or treatment of
disease.
• When administered appropriately, drug can cause
a range of physiological and
biochemical/molecular changes in a complex
biological system that relate to its composition,
structure and target
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8. Where do drugs come from?
• Plants
• Human-derived proteins/steroids
• Fungi/bacteria
• Synthetic chemicals
• Recombinant proteins
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9. I. General Principles of Pharmacology
1. Sources and Nature of Drug Dosage Form
2. Prescription Writing
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10. Sources and Nature of Drug Dosage
Form
Modern drugs are obtained from many sources:
1. 50% of total prescriptions are composed of
synthetic or semisynthetic (based on natural
active ingredients) chemical agents
Natural:
1. 25% contain plant resources
2. 12% are microbial-derived products
3. 7% are mineral in character
4. 6% are animal-derived
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11. Classification of drug sources
• Natural sources of drugs
1. Plants: the whole plant, leaves, root, bark,
seeds, flowers
2. Microorganisms: bacteria, fungi, …
3. Minerals
4. Animals: organs, tissues, fluids
• Synthetic sources of drugs
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12. Natural sources of drugs, examples
Plants
• The active ingredients might be found in any part (or all
parts) of the plant
Microorganisms
• Microbial metabolites used as drugs, especially the
antibiotics and antineoplastic agents. Examples:
1. a strain of mold Penicillium chrysogenicum produces
Penicillin G
2. Clavulanic acid is a product of fungus Streptomyces
species
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13. Natural sources of drugs
3. Minerals
1. Purified sulfur is used internally only, as a
laxative
4. Animals
Animal sources: organs, tissues, fluids:
1. Beef and pork pancreas are the source of the
natural insulin sold today
2. Exogenous thyroxine can be obtained from the
thyroid glands of animals, usually pigs
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14. Synthetic sources of drugs
• Many new drugs have been synthesized.
• Semisynthetic drugs are based on natural
ingredients:
1. Morphine and synthetic analgesics
2. Hormones, vitamins, synthetic antibiotics are
only a small part of the modern drugs,
produced by synthesis.
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16. DRUG DOSAGE FORMS
CLASSIFICATION OF DRUG DOSAGE FORMS
Drug substances are developed into drug dosage forms in
order to optimize stability, safety and effectiveness of drug
substances and to make them suitable for administration.
According to the consistence, they are classified as:
1. Solid dosage forms
2. Liquid dosage forms
3. Semisolid dosage forms
4. Aerosols
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17. Characteristics of solid dosage forms
• POWDERS
• oral powders – e.g., antacid and laxative
powders
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18. TABLETS
Tablets prepared by compression. This is the
most frequently used dosage form of
administering a drug.
Tablet types and their abbreviations:
 compressed (or plain) tablets (CT) – These
tablets are formed by compression and
contain no special coating. E.g. paracetamol
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19. Sublingual tablets
• small and dissolve rapidly.
• they are placed under the tongue and allowed to
dissolve after absorption
• the drug enters the systemic circulation without
passing through the portal circulation, thus avoiding
first-pass inactivation in the liver
• Drugs that are destroyed by the GI fluids or are
subject to 1st pass metabolism may be formulated
into such tablets. E.g: Nitroglycerin
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20. • chewable tablets are large, hard tablets,
difficult to swallow, intended to be crushed
before ingesting.
• effervescent tablets contain sodium
bicarbonate and an organic acid in addition to
the drug substance. In the presence of water,
these additives react liberating carbon dioxide
which acts as disintegrator and produces
effervescence. E.g. Vit C
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21. • film-coated tablets (FCT):
are compressed tablets which are covered with
a thin layer or a film of polymeric substances to
protect their contents from moisture or to mask
the taste of the ingredients. e.g:
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22. enteric-coated tablets (ECT)
• are coated with substances that resist solution in
gastric fluid but disintegrate in the alkaline contents
of the intestine.
• Enteric coating is used for drugs with a gastric
irritant action, for drugs which are unstable in the
acid medium of the gastric contents or if the drug
should act on the intestine. e.g., Diclofenac Na.
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23. • controlled-release tablets
• are formulated to release the drug slowly over
a prolonged period of time.
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24. CAPSULES
Capsules are solid dosage forms in which the drug
substance is enclosed in either a hard or soft soluble
container of suitable form of gelatin:
• Hard gelatin capsules
• Soft elastic capsules (SEC) are soft, gelatin shells
somewhat thicker than that of hard gelatin.
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25. GRANULES
• Granules are dosage forms related to
powders. They are particularly suitable for the
preparation of solutions or mixtures of drugs,
such as antibiotics, that are unstable in the
presence of water
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26. CHARACTERISTICS OF LIQUID DOSAGE
FORMS
• SOLUTIONS
Solutions are homogeneous mixtures that are
prepared by dissolving a solid, liquid, or gas in
another liquid.
• EMULSIONS
Emulsions are two-phase systems that are
normally immiscible in which one liquid is
dispersed throughout another liquid in the form of
small droplets.
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27. SUSPENSIONS
Suspensions are two-phase systems consisting
of finely divided solids dispersed in liquids. If the
drug is insoluble or poorly soluble, a suspension
may be the most suitable dosage form.
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28. DROPS
Drops are intended to be administered
internally or externally (as eye drops or
collyrium, nasal, and otic drops). Drops are
prescribed in small quantity (10 – 30 g).
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29. STERILE DOSAGE FORMS FOR
INJECTION
• They differ from all other drug dosage forms because
of their unique use for injection directly into body
tissue through the primary protective systems of the
human body, the skin and mucous membranes.
Therefore, they must be exceptionally pure and free
from contaminants
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30. CHARACTERISTICS OF SEMISOLID
DOSAGE FORMS
OINTMENTS are semisolid preparations
intended for external application to the skin or
mucous membranes.
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31. TYPES OF OINTMENTS
• OINTMENTS (oil 80% - water 20%) are prepared of
solid active ingredients (1–25%), finely powdered and
then incorporated into the oleaginous base. They can
be: ointments for skin application, eye ointments, nose
ointments.
• PASTES contain powders dispersed in the vehicle in
quantity more than 25%. They are usually stiffer, less
greasy and more absorptive than ointments. Pastes
adhere reasonably well to the skin and they are suited
for application on and around moist lesions.
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32. • CREAMS: similar to ointments. A cream is an
emulsion of oil and water in approximately
equal proportions
• GELS or jellies are semisolid dosage forms
with high degree of clarity, ease of application
and ease of removal and use. The active
ingredients are incorporated into water-
soluble bases. The gels often provide a faster
release of drug substance as compared to
creams and ointments.
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33. • SUPPOSITORIES
Suppositories are solid dosage forms of various
weights and shapes for insertion into the rectum or
vagina
• PLASTERS
Plasters are substances intended for external
application. They are intended to bring medication into
close contact with the skin. medicated plasters are
used for local or regional drug delivery
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34. AEROSOLS (SPRAY)
• These drugs are designed to carry the drug into the respiratory tree of the
patient or on the skin and mucous (nasa, etc.)
• Aerosols are heterogeneous systems consisting of very finely subdivided
liquid or solid particles (optimum size 0,5–3 μm) dispersed in a gas
medium. They can be inhaled (nasally or orally) or applied topically to
dispense a variety of agents for treatment of systemic and topical
diseases.
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35. Nebulizers
• Nebulizers are devices used for administration of solutions giving
sufficiently small droplets.
• Advantages: rapid onset of action; bypass the hepatic circulation;
avoidance of degradation in the GI tract; lower dosage that minimizes
adverse reactions; simple, convenient and acceptable therapy.
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36. Principles of Prescription Writing
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37. History
• Prescriptions have been in use since ancient times
– Latin adopted as standard language
– “Rx” = prescription
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38. Definition
A prescription is a
written, verbal, or
electronic order
from a practitioner
or designated agent
to a pharmacist for a
particular
medication for a
specific patient.
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39. Prescription Formatting
• Heading
• Body
• Closing
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40. Current Prescription Formatting
• Heading
–Name, address, and telephone
number of the prescriber
–Name, sex and age of the patient
–Date of the prescription
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42. Current Prescription Formatting
• Body
–The Rx symbol
–Name
–dose size or concentration
(liquids) of the drug
–Amount to be dispensed
–Directions to the patient
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43. Contents of the “body”
• Name of the drug
AVOID THE USE OF:
–Abbreviations
• Many drugs identified with abbreviations
–EX: HCT for hydrochlorothiazide, MSO4
for morphine sulfate
• Attempts to standardize abbreviations
have been unsuccessful
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44. • Tablets - tab
• Capsule – cap
• Syrup – syr
• Suspension – susp
• Injection – Inj
• Metered dose inhaler – as such
• Lotion – as such
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46. Sample Prescription-
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47. Current Prescription Formatting
• Closing
–Prescriber’s signature
–Refill instructions
–Generic substitution
instructions
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49. Controlled Substances
Legally, drugs are classified into 3 categories:
1. OTC : Over The Counter drugs
2. POM : Prescription Only Medications
3. Controlled Drugs: - a prescription drug
whose use and distribution is tightly
controlled because of its abuse potential or
risk
• Regulation is more strict
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50. Prescription for controlled drugs must
(e.g. morphine)
1. Be completely written in the prescriber’s hand writing
in ink
2. Be signed & dated
3. Carry the prescribers’ address
4. Carry the name & address of the patient
5. State the form of the drug
6. State the total quantity of the drug or the number of
dose units to be disposed in both words & figures
7. State the exact size of each dose in both words &
figure. 50

51. CASE
A hypertensive patient accidentally received Vantin 200 mg
instead of Vasotec 20 mg when a pharmacist misread this
prescription
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52. MAXIMIZE PATIENT SAFETY
• ALWAYS space out words and numbers to
avoid confusion.
• ALWAYS complete medication orders.
• AVOID abbreviations.
• When in doubt, ask to verify.
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53. Summary:
Contents of the Prescription
–Date of the order
–Patient Name and Address
–Name of the drug
–Strength of the drug
–Quantity of the drug
–Directions for use
–Practitioner Name, Address, Telephone
number
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54. Grouping of drugs:
Pharmacologic class (or family):
– drugs that share similar characteristics
– Example: beta-adrenergic blockers are an example
of a pharmacologic class.
Therapeutic class:
– groups drugs by therapeutic use.
– Example: Antihypertensives
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