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Chapter 1
Studying Pharmacology
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Chapter 1
Topics
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Phases of Pharmacology
Strategies for Learning Pharmacology
Drug Classifications
Common Pharmacy Abbreviations and Terms
Dosage Forms and Routes of Administration
Topical Routes of Administration
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Phases of Pharmacology
Introduction
• Drugs are used for preventing, treating, and curing illness
• Sources of drugs
 Natural sources include plants, animals, and minerals
 Synthetic processes and bioengineering methods
• Pharmacology is the study of how drugs from these
sources work inside the body for their intended purposes
• Physiology (the study of normal body function) is useful to
learn how drugs affect body processes
• Pathophysiology (the study of abnormal body processes
or disease) is also important to learn
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Phases of Pharmacology
The Three Phases
• Are pharmaceutics, pharmacokinetics, and
pharmacodynamics
Pharmaceutics
• Is the study of how drugs enter the body
 Many oral drug dosage forms (capsules, tablets, and
liquids); also spread on skin, inhaled, injected, and
inserted
• Studies how the forms deliver a drug to the body and
achieves desired drug absorption into the bloodstream
• Focuses on dosage forms and routes of administration
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Phases of Pharmacology
Pharmacokinetics
• Is the study of what the body does with drugs
 Absorption: how drugs are absorbed into the
bloodstream
 Distribution: how drugs are circulated to tissues
throughout the body
 Metabolism: how drugs are inactivated (metabolized)
 Excretion: how drugs are eliminated from the
bloodstream over time
• Focuses on how these four processes affect the
effectiveness, dosing schedule, and use of drugs
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Phases of Pharmacology
Pharmacodynamics
• Is the study of drugs and their receptors on the molecular
level (what the drugs do to the body)
• Focuses on translating chemistry to drug activity within the
entire body
Pharmacotherapeutics
• Is the study of how drugs are used in clinical practice for
individual patients
• Focuses on the use and study of drugs in people
 Pharmaceutics and pharmacokinetics are laboratory
sciences
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Phases of Pharmacology
How a Drug Works
• Enters the
bloodstream (I.)
• Reaches the site of
action in sufficient
concentration (II.)
• Interacts with
appropriate
receptors to
cause a beneficial
effect (III.)
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Strategies for Learning Pharmacology
How to Learn Pharmacology
• You must remember many drug names and understand
mechanisms of action for this course
 Learn the rules for each drug class and connect the
individual drugs to that set of rules
 Learn the exceptions to rules (often side effects)
• Find out your preferred methods of learning
 Take a learning styles inventory
 Use the “Your PILS” feature(s) in the chapters to help
you learn in ways that make sense to you
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Drug Classifications
Brand versus Generic Drug Names
• Drugs
 Are categorized in various ways, some based on legal
divisions and others on mechanism of action
 Must be tested before it is marketed
 Has three different names during testing process
Chemical name of new medical molecule
Generic name assigned by government agency
Brand name assigned by company that will
manufacture and sell it; easier to pronounce than
generic name
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Drug Classifications
Brand versus Generic Drug Names (continued)
• Phase I clinical trials
 Drug is tried in healthy human subjects
 Generic drug name assigned
• Phase II and Phase III clinical trials
 Drug is tested in human having condition or disease the
drug is meant to treat
 End of Phase III FDA approval sought and brand name
assigned
• Phase IV clinical trials
 Called postmarketing study
 Brand name trademarked and used for marketing
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Drug Classifications
Brand versus Generic Drug Names (continued)
• Pharmacy Technicians must know both generic and brand
names of drugs due to generic substitution
• Generic substitution occurs often
 Physicians’ prescriptions are often written in brand
name
 Pharmacies are organized by generic name and
prescriptions are filled with generic product
• Generic names are often similar
 Makes it easy to determine a drug’s class, mechanism
of action, and uses
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Drug Classifications
Major Drug Classes
• Are groups of medications categorized according to their
mechanism of action
 Usually given similar names with a common stem (see Table
1.1)
• Therapeutic classes
 Are individual drug classes grouped according to their use on
a particular body system
• Generic drug names within a class are often similar; this helps to
know drug actions and therapeutic uses
• “Look-alike” and “sound-alike” drug names cause errors
• ISMP publishes a confused drug list names on its Web site
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Drug Classifications
Prescription versus OTC Medications
• Prescription (legend) drugs
 Are medications available only by prescription
 Dispensed from a pharmacy on receipt of a prescription
from a prescriber
 Have legal limitations to dispensing
• OTC medications
 Can be bought without a prescription
• New drugs enter the market as prescription medications
 Move to OTC status if safe enough to be used by
patients without medical supervision
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Drug Classifications
Controlled versus Noncontrolled Substances
• Controlled substances
 Are medications with potential for abuse and dependence
categorized by the U.S. DEA
 Are placed into one of five schedules, based on their
degree of potential for abuse
• Schedule I substances
 Are illegal or only available for research or experimental
purposes
• Schedule II–V drugs
 Are legally dispensed with restrictions on numbers of
refills and quantity
 Dispensing procedures and inventory control measures
are strictly regulated at the federal and state levels
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Drug Classifications
Controlled versus Noncontrolled Substances (continued)
• Schedule II has the most stringent restrictions (see Table 1.2
for description of controlled substances schedules)
• Precursors
 Can be used to make crystal methamphetamine
 Sale of precursor is limited in pharmacies
 Examples: pseudoephedrine and phenylpropanolamine
 Have legitimate medical uses and when used properly do
not cause dependence or abuse
 Sale of precursor is limited; purchased if over eighteen
years old and must be stored behind counter in the
pharmacy
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Drug Classifications
Pregnancy Categories
• All drugs marketed in the United States receive a
pregnancy categorization of A, B, C, D, or X (see Table 1.3)
• Category A drugs are safest during pregnancy
• Category X drugs are contraindicated in pregnancy
• Teratogenic drugs
 Can cause birth defects or malformations in a fetus
• Breast-feeding characteristics
 No special categorization system available
 Technicians should refer patients inquiring about drug
safety to the pharmacist
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Your Turn
Question 1: Before a drug is marketed, it must be tested. What
is the difference between the generic name and the brand
name of a drug during this process?
Answer: A generic drug name is assigned to a medical
molecule by a government agency and is used during Phase
I, II, and III clinical trials. Near the end of Phase III, a brand
name is assigned by the company that will manufacture and
sell the drug.
Question 2: What restriction applies to a drug that is in the
pregnancy category of X?
Answer: The drug cannot be given to patients during
pregnancy.
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Drug Classifications
Alternative and Complementary Treatments
• Western medicine
 Called traditional medicine
 Relies on observation and experimentation
• Eastern medicine
 Uses herbs and alternative therapies
 Recognizes holistic strategies and natural ingredients
• Vitamins and herbal products
 Are dietary and nutritional supplements
 Regulated by FDA as food, not as drugs
 Are not regulated for safety and efficacy
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Drug Classifications
Alternative and Complementary Treatments
(continued)
• Homeopathy
 Involves very diluted substances (often herbs) used for
treating an ailment
• Chinese medicine
 Eastern medical philosophies of holistic health
 Employs balance of yin and yang
 Often uses acupuncture and herbs and acupressure
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Drug Classifications
Alternative and Complementary Treatments (continued)
• Chiropractic therapy
 Uses nondrug modalities such as manipulation for body
alignment and health
• Ayurveda
 East Indian medicine
 Involves spiritual and whole-body well-being and
employs diet and lifestyle changes
• Biofeedback
 A method used to control body function
 Uses mental exercise and relaxation to slow heartbeat,
lower blood pressure, and reduce stomach problems
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Common Pharmacy Abbreviations and Terms
Pharmacy Abbreviations
• Used along with prescribing terms by most prescribers for
writing prescriptions and medical orders
• Are usually based on Latin or Greek terms
Medication Errors
• A patient is harmed by a medication in some way that
could have been prevented
• Technicians need to be careful in the use and
interpretation of abbreviations to avoid harm to patients
• Correct drug administration involves giving the right drug
to the right patient at the right time in appropriate
strength and route
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Common Pharmacy Abbreviations and Terms
Correct Drug Administration: Five Rights
• Is the correct patient listed on the
drug order?
• Does the dose ordered make sense
for this drug?
• Does the strength ordered make
sense for the drug and its dosage
form?
• Is the frequency or timing of doses
appropriate?
• Does the route of administration
match up to the drug, its intended
use, and the dosage form ordered?
A problem with any “five
rights” can result in
medication error
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Common Pharmacy Abbreviations and Terms
Medication Errors (continued)
• ISMP
 Publishes a list of abbreviations most pharmacies and
institutions are trying to eliminate from use
List is long and changes periodically
Updated ISMP Table of Error-Prone Abbreviations is
on the ISMP Web site
• Technicians must promote accuracy and patient safety,
including curbing use of dangerous abbreviations
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Dosage Forms and Routes of Administration
Systemic Effect and Local Effect
• Drugs are administered in a way to reach the site of action
in a sufficient amount to produce desired effect
• Drug delivery
 Depends on the dosage form (how it is delivered)
 Depends on the route by which it is administered
• Systemic effect
 Drugs enter the bloodstream to reach its site of action
 Drugs are absorbed or administered directly into
bloodstream
• Local effect (topical)
 Drugs are administered directly without first traveling
through the bloodstream
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Dosage Forms and Routes of Administration
Systemic Routes of Administration
• Used when a drug is intended to enter the bloodstream
and travel to its site of action
• Enhances drug delivery because a variety of dosage forms
are available for each systemic route
 Allows the use of the most effective form for a patient
 Provides options for patients with difficulties taking or
using any one route
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Dosage Forms and Routes of Administration
Systemic Routes and Corresponding Dosage Forms
Route of
Administration
Oral
Most Common Dosage Forms
Tablet, capsule, liquid, suspension
Buccal or sublingual Tablet, spray, lozenge, troche
Parenteral
Injectable, solution, some
suspensions
Rectal
Suppository, solution
Transdermal
Implant
Patch, paste, cream, ointment
Drug encasement carrier
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Dosage Forms and Routes of Administration
Systemic Routes: Oral
• Means giving a drug by mouth (peroral or PO)
• Most convenient and cost-effective method for systemic
route
• Most medications today are pills (tablets or capsules)
 Are usually swallowed whole, then absorbed into
bloodstream by the GI system
• Dosage forms include tablets, pills, and syrups
 Tablets can be coated or uncoated and some are
chewed; also ODTs, sublingual, and buccal are available
 Oral liquids such as solutions and suspensions (shake
before dose) are also available
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Dosage Forms and Routes of Administration
Systemic Routes: Parenteral
• Administered by injection
 Used for patients who are unconscious or cannot
swallow when rapid action is needed
 Used for drugs that have a large first-pass effect
Systemic Routes: Parenteral—IM Injection
• Are given directly into a muscle
 Most common injection sites are the deltoid in the
upper arm and the gluteus medius in the buttocks
 Most common dosage form is solution
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Dosage Forms and Routes of Administration
IM Injection
• Typically, a 1-inch
needle is used
• Needle is injected at
a 90-degree angle
so that the drug is
administered within
the muscle tissue
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Dosage Forms and Routes of Administration
Systemic Routes: Parenteral—IV Injection
• Are given directly into a vein
• Continuous infusion—small catheter inserted into a vein
while IV fluid with the drug runs through it into the blood
• Peripheral IV line—inserted into vein in arm, wrist, or hand
 Used when small amounts of fluid are given or the time
over which the fluid will infuse is a few days or less
• Central IV line—inserted surgically into a large vein in the
upper chest area near the clavicle (collarbone)
 Used for large volumes of fluid, many repeated
infusions, or infusions of more than few days
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Dosage Forms and Routes of Administration
IV Injection
• The size and angle
of the needle used
depend on the area
of the body and the
vein into which the
drug is delivered
• Dosage form is IV
solutions
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Dosage Forms and Routes of Administration
Systemic Routes: Parenteral—SC Injection
• Are given into the fatty tissue under the dermal layer of
the skin and above the muscular tissue
• Common injection sites include abdomen, upper thigh,
and back of the upper arm
 Drug is absorbed by the blood supply over a few
minutes to hours
• Dosage forms are solutions and some suspensions
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Dosage Forms and Routes of Administration
SC Injection
• For delivery of
insulin a very fine,
short needle is
injected at a 90degree angle
• For delivery of other
drugs a 1-inch
needle is injected at
a 45-degree angle
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Dosage Forms and Routes of Administration
Systemic Routes: Parenteral—IT and Epidural
• IT
 Are injections given into the spinal column between
vertebrae in the back
• Epidural
 Use a small catheter to deliver a drug directly into the spinal
column over time
• Both used for regional anesthesia such as childbirth and delivery
• Anesthesiologists or anesthetists administer injections
• Technicians may be involved in preparing products if their
institution supports surgical or birth and delivery services
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Dosage Forms and Routes of Administration
Systemic Routes: Parenteral—ID
• Are injections given just underneath the top layer of skin
(epidermis)
• Used for TB skin tests (PPD), local anesthesia, and allergy
skin testing
• Usually not prepared by a pharmacy
• Technicians and other healthcare workers may be required
to get an annual PPD test for TB exposure
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Dosage Forms and Routes of Administration
Intradermal
Injection
• After an ID TB
injection, patient
returns in two to
three days for
examination of the
injection area
• Redness and
swelling at the site
indicate possible
exposure to TB
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Dosage Forms and Routes of Administration
Systemic Routes: Rectal
• Are drugs inserted into the rectum to melt or dissolve
• Mostly intended for systemic effect but a few for local
activity, such as treating hemorrhoids
• Common dosage forms include suppositories and enemas
Systemic Routes: Transdermal
• Application of a drug delivery system, such as a patch with
adhesive backing, is applied to the skin
• Drug is slowly and evenly absorbed through skin over time
Systemic Routes: Implant
• Inserted just below the skin to release a drug slowly
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Dosage Forms and Routes of Administration
Topical Routes of Administration
• Used for local effect not for systemic absorption
• Delivered topically to lung tissue, eyes, and vagina
Topical Routes: Dermal
• Applied topically to the skin
• Dosage forms include creams, lotions, gels, ointments,
powders, solutions, and pastes
• Used to treat local infections, wounds, sunburns, and
rashes
• Systemic absorption possible if large amount in large
area
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Dosage Forms and Routes of Administration
Topical Routes: Inhalation
• Administration of a drug into the lungs by breathing it in
through the mouth
• Allows for direct treatment to lung tissue
• Devices: metered dose inhalers, dry powder inhalers, and
nebulizers
Topical Routes: Intranasal
• Are sprayed into the nose
• A dosage form (solution) delivers drug to nasal mucosa
• Patients should not sniff forcefully when administering
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Your Turn
Question 1: A patient will receive a flu shot at the pharmacy.
What is the likely location of the injection site?
Answer: The patient will probably have the injection in the
deltoid muscle in the upper arm.
Question 2: What is the purpose of administering a drug by
inhalation?
Answer: This route provides the drug directly to lung tissue.
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Dosage Forms and Routes of Administration
Topical Routes: Ophthalmic
• Delivered topically to the eye
• Dosage forms are eyedrops and eye ointments
Topical Routes: Otic
• Delivered into external ear canal
• Dosage forms are eardrops, both solutions and
suspensions
Topical Routes: Vaginal
• Inserted and applied into the vagina
• Dosage forms include creams, gels, solutions,
suppositories, ointments, and tablets
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Dosage Forms and Routes of Administration
Ophthalmic Administration
Applying Eyedrops
Applying Ointment
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Dosage Forms and Routes of Administration
Otic Administration
• Patients turn
their head
horizontally
• Pull on earlobe
while squeezing
the bottle to
allow drops to
fall into ear
canal
Pull upward
for adults
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Pull downward
if under age
three
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Summary
• Pharmacology is the study of how drugs work in the body
• Drugs are categorized by classes with similar mechanisms
of action
• Drugs are also either prescription (legend) or OTC
• Some prescription medications are controlled substances
• Medications are ranked into pregnancy risk categories
• FDA does not regulate dietary, herbal products, or
vitamins
• Many common routes of drug administration and dosage
forms for each route
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