Pharmacotherapy

PHARMACOTHERAPHY

Lecture Outline

Definition

Pharmacotherapy

Drugs

Medicine

Sources of Drugs

Drug Nomenclature

Drug Classification

Non-Rx Drugs

Illegal Drugs

Sources of Drug Standards

Standards of Practice

Pharmaceutical Dosage Forms

The Rx

Administration of Medication

Drug action

Drug Effects

Sources of Drug Information

Pharmacotherapy

application of drugs in the prevention,

treatment or diagnosis of disease and their

use in purposeful alteration of normal

functions

Pharmacotherapy

division of Pharmacy which correlates

pharmacokinetics and pharmacodynamics

aspect.

Pharmacokinetics- The study of the

absorption, distribution, metabolism, and

excretion (ADME) of drugs by living

organisms.

Pharmacodynamics- The study of the

biochemical and physiologic mechanisms

of drug action.

Drugs

chemical substances that have an effect on

living organisms.

Therapeutic drugs often called medicines, are

those drugs used in the prevention or treatment

of diseases.

Up until a few decades ago, dried plants were

the greatest source of medicines; thus the word

“drug” was applied to the active ingredient.

Drug vs Medicine

Drug • any substance that alters physiologic function

w/potential for affecting health.

• Refers to “active ingredient”

• Could be poison

Medicine • drug administered for therapeutic effects

• Refers to “ active + inactive ingredients”

– All medications are drugs

– Not all drugs are medications

Sources of Drugs

Drugs are obtained from many sources.

1. Natural Sources:

Hormones, alkaloids, vaccines, and antibiotics come

from living organisms; Chemotherapeutics are from

many inorganic materials, such as metals. Other examples:

Plants - digitalis and opium

Animals - insulin and thyroid

Minerals or mineral products - potassium, chloride, and lithium

carbonate

Sources of Drugs

Drugs are obtained from many sources.

2. Other drugs are synthetic or semisynthetic.

- Synthetics are often more effective and less toxic than the naturally

obtained substances and are easier to prepare in standardized units.

Synthetic chemical compounds - barbiturates, sulphonamides, and aspirin.

Biotechnology - genetically engineered pharmaceutical products

Drug Nomenclature

Drugs used as therapeutic agents may be

conveniently divided into two main groups:

(1) nonprescription drugs

(2) prescription drugs

Drug Names: Chemical Name

exactly the chemical constitution of the

drug and the exact placing of its atoms or

molecular groupings.

chemical name composition of the drug by

its molecular structure

Example: acetylsalicylic acid

Generic Name

(Nonproprietary Name)

provided by the United States Adopted

Names (USAN) Council

Is equivalent to the same drug with a brand

name, but is less expensive

Example: Aspirin

Drug Name: Official Name

name under which the drug is listed by the

U.S. Food and Drug Administration (FDA).

FDA- empowered by Federal Law to name

drugs for human use in the U.S.

Trademark (Brand Name)

followed by the symbol ®. This indicates

that the name is registered and that its use is

restricted to the owner of the drug, who is

usually the manufacturer of the product.

Should have a consistent bioavailability

More easily recognized by appearance.

Example: Bayer

Drug Classifications

Drugs may be classified:

1. According to the body system they affect

2. According their therapeutic use or clinical indications

3. According to their physiologic or chemical action

4. According to prescription or non-prescription drugs

Drug Classification Indicates

Effect on a body system

Symptoms relieved

Desired effect

Classification of Drugs (effect on the body system)

Joint Drugs

Blood Coagulants Anticoagulants

Hemorrheologic Agents

Dental Agents

Ears, Eyes and Nose Vasoconstrictors

GI Enzyme and Acid Agents

Gastrointestinal Muscle Movement Agents

Genitourinary Muscle Relaxants

Nervous System Skeletal

Muscle Relaxants

Nervous System

Stimulants

• Respiratory Antitussives,

Expectorants, and

Mucolytics

Respiratory Smooth

Muscle Relaxants

Skin & Mucous

Membrane Agents and

Enzymes

Classification of Drugs (Clinical indications or therapeutic uses)

Antihypertensives

Mucolytics

Laxatives

Antibiotics

Analgesics

Antitussives,

Classification of Drugs

(physiologic/ chemical action)

Glaucoma Agents

Adrenal agents Glucocorticoids

Mineralocorticoids

Pituitary Agents

Reproductive Agents

Thyroid Agents

Adrenergic Agents

(Sympathomimetic)

Anticonvulsants, Sedatives & Hypnotics

Tranquilizers

Cholinergic and Anticholinergic Agents

Serums, Toxoids, &

Vaccines

Vitamins and Caloric

Agents

Classification of Drugs (physiologic actions/ chemical actions)

Antineoplastic Agents

Cardiac Muscle Drugs

Diuretics

Antihistamines

Anti-Infective Agents Antifungal Antibiotics

Anti-Inflammatory Agents

-Steroids

-Non-steroidal Agents

Non-Prescription Drugs

over the counter medications (OTC)

which can be purchased by anyone.

No Rx needed

Examples: Tylenol, Maalox, Tums

Illegal Drugs

Illegal drugs- recreational drugs

Drugs and chemical substances used for

non-therapeutic purposes

Obtained illegally or have not received

approval for use by the FDA

Sources of Drug Standards

United States Pharmacopoeia

USP verifies the identity, strength, purity,

and quality of dietary supplement finished

products, dietary supplement ingredients,

and pharmaceutical ingredients.

A National Formulary

a manual containing a list of medicines that

are approved for prescription throughout the

country, indicating which products are

interchangeable.

USP Dictionary of USAN and

International Drug Names

database contains more established drug

name listings than any other comparable

resource.

Drug Standards Ensure

Strength or potency

Purity

Efficacy

Safety

Bio-availability

Standards of Practice

Information for Administering Medications

– Generic Name/Trade Name/Classification

– Clinical Uses/Safe Dosage

– Mechanism of Action

– Side Effects/Adverse Effects

– Contraindications/Precautions

– Significant Drug Interactions

– Monitoring Needs/Patient Education

– Evaluation of Effectiveness

Pharmaceutical Dosage

Forms

Drug substances are seldom administered

alone, but rather as a part of a formulation

in combination with one or more no medical

agents that serve varied and specialized

pharmaceutical functions.

Types of Dosage Forms

Syrups

Elixirs

Suspensions

Emulsions

Capsules

Tablets

Creams

Ointments

Suppositories

Aerosols

Parenteral

Introduction to Drug Dosage

Prescription

comes from the Latin "praescriptus"

compounded from "prae", before + scribere,

to write = to write before.

Historically, a prescription was written

before the drug was prepared and

administered.

Parts of a prescription

The superscription (or heading) with the

symbol R or Rx which stands for the word

“Recipe” meaning (in Latin) “to take” or “

take thou”;

The Rx

The inscription which contains the names and quantities of the ingredients;

The subscription or directions for compounding the drug to the pharmacist

Transcription- signa, direction to patient

The signature which is often preceded by the sign s. standing for signa, mark, giving the directions to be marked on the container.

Administration of

Medications

Route of administration

the path by which a drug, fluid, poison or other

substance is brought into contact with the

body.

Mode of drug administration affects the rate at

which onset of action occurs and may affect

the therapeutic response that results

crucial in determining the suitability of a drug

Routes of Administration

Enteral - drug administered along any

portion of GI tract

– Sublingual, Oral, Buccal, Rectal, Nasogastric

Routes other than alimentary canal

– IV, IM, ID, SQ, Instillation, Inhalation,

Topical, Transdermal,

Drug Action

biochemical

physiological

mechanisms by which

the chemical produces

a response in living

organisms

Three Phases of Action

Copyright © 2003 by W. B. Saunders Company. All rights reserved.

First Pass Effect

Drugs given orally and absorbed from GI tract

Carried to the liver

Extensively metabolized

Only part of the dose reaches systemic circulation for distribution

Bioavailability -%of drug that reaches systemic circulation

First pass/hepatic first pass

– Enter liver first

• Coumadin

• Morphine

• Lidocaine

• Some NTGs

Drug Effects

Therapeutic effects (primary)

Side effects (secondary)

Adverse effects (secondary)

Toxic effects (secondary)

Desired effect

– Therapeutic effect-example

Adverse effect / Side effect

– Harmful, undesirable response

– Mild reactions to debilitating disease that can become chronic

Dose related or patient sensitivity

Drug allergy - patient’s immune system identifies a drug as dangerous to the body….must be destroyed or neutralized-mild itching to life threatening

Adverse drug reactions

any noxious unintended and undesired

effects of a drug that occur at doses used for

prevention, diagnosis or treatment.

ADR

Type “A” reactions

AUGMENTED

Predictable, common and related to

pharmacological action of the drug

ex. Side effects, secondary effects, drug

interaction

ADR

Type “B” reactions

BIZAARE

Unpredictable, uncommon, usually not

related to the pharmacological actions of

the drug.

ex. Idiosyncratic reaction,

pseudoallergenic, hypersensitivity

ADR

Type “C” reactions

CONTINUOUS

associated with long-term drug therapy e.g. Benzodiazepine dependence and Analgesic nephropathy.

are well known and can be anticipated.

ADR

Type “D” reactions

DELAYED

refer to carcinogenic and teratogenic

effects.

are delayed in onset and are very rare since

extensive mutagenicity and carcinogenicity

studies are done before drug is licensed.

ADR

Type “E” reactions

ENDING OF USE

Withdrawal syndromes • Alcohol (delirium tremens)

• Barbiturates (restlessness, mental confusion,

convulsions

• Opioids (narcotic withdrawal)

ADR

Type “F” reactions

FAILURE OF EFFICACY

Result of imperfect or counterfeit manufacture of the product.

Examples of failed efficacy: • Failure to control infection

• Uncontrolled HPN

• Intractable pain

Idiosyncratic response

Something out of the ordinary

– Sensitivity related adverse reactions….

– Specific to the individual patient

– Sometimes has genetic cause

– They don’ t know

Idiosyncratic Reactions vs.

Allergic Reactions

idiosyncratic reaction--an uncharacteristic,

non-immunological response to a drug that

is not related to its pharmacological actions

“allergic” or “hypersensitivity reaction”--

immunologically mediated

Toxic Reactions

--Occur in response to high dose or long-

term use but may occur with normal

doses if drug elimination is impaired.

--May cause organ dysfunction, blood

disorders (physiological toxicity) or

behavioral changes (behavioral

toxicity).

Toxicity vs. Carcinogenicity

Toxicity--something that will make you

sick, either right away or later.

Carcinogencity--will cause cancer, which

maybe the results of being exposed to

something toxic.

Allergic Reactions vs. Non-

allergic drug reactions

In a drug allergy, your immune system

mistakes a medication for a disease-causing

agent.

Nonallergic drug reactions have a wide

variety of causes, including the drug's

intended mechanism of action.

Allergic Reactions

Indicated by skin reactions ranging from mild rashes to flaming red patches of hives.

More severe reactions cause facial swelling, shortness of breath or dizziness.

Anaphylaxis (rare)--an extremely severe allergic reaction in which blood pressure may fall rapidly and the throat may rapidly swell shut, cutting off the airway.

Hypersensitivity

allergic response to a drug after it has been

used more than once

May cause rash, swelling, fever, or, in the

worst cases, anaphylactic shock

(hypotension, bronchospasm, blocking or

airways).

Carcinogencity

study to determine the propensity of a drug

to produce or exacerbate tumors or cancer

cells in humans or animals

Teratogenicity

study to determine whether a drug can cause

physical defects in a developing embryo.

Common or Serious Side Effects

CNS effects

Gastrointestinal effects

Hematological effects

Hepatotoxicity

Nephrotoxicity

Allergic or hypersensitivity reaction

Drug fever

Idiosyncratic reaction

Carcinogenicity

Teratogenicity

Drug dependence

Drug tolerance

Sources of Drug Information

Pharmacology textbook

Pharmacists

Internet sources

Journal articles

Drug reference books

What you should know

about drugs……