2© paradigm publishing, inc. chapter 1 studying pharmacology

© Paradigm Publishing, Inc. 2

Chapter 1

Studying Pharmacology


Chapter 1

Topics

• Phases of Pharmacology• Strategies for Learning Pharmacology• Drug Classifications• Common Pharmacy Abbreviations and Terms • Dosage Forms and Routes of Administration • Topical Routes of Administration


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



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



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



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



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.)


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


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 moleculeGeneric name assigned by government agencyBrand name assigned by company that will

manufacture and sell it; easier to pronounce than generic name



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



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



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



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



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



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



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


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.



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



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



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


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



Correct Drug Administration: Five Rights

A problem with any “five rights” can result in

medication error

• 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?



Medication Errors (continued)• ISMP

Publishes a list of abbreviations most pharmacies and institutions are trying to eliminate from use

List is long and changes periodicallyUpdated 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


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



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



Systemic Routes and Corresponding Dosage FormsRoute of Administration

Most Common Dosage Forms

Oral Tablet, capsule, liquid, suspensionBuccal or sublingual Tablet, spray, lozenge, trocheParenteral Injectable, solution, some

suspensionsRectal Suppository, solutionTransdermal Patch, paste, cream, ointmentImplant Drug encasement carrier



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



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



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



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



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



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



SC Injection• For delivery of

insulin a very fine, short needle is injected at a 90-degree angle• For delivery of other

drugs a 1-inch needle is injected at a 45-degree angle



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



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



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



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



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



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


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.



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



Ophthalmic Administration

Applying Eyedrops Applying Ointment



• Patients turn their head horizontally• Pull on earlobe

while squeezing the bottle to allow drops to fall into ear canal

Pull upward for adults

Pull downward if under age

three

Otic Administration


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

2© paradigm publishing, inc. chapter 1 studying pharmacology

Documents

study of drugs

pharmacology slide

individual drugs

drugs absorption

generic drug names drugs

drug activity

drug works

body metabolism