Pharmacology

CHAPTER 22

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Pharmacology Overview

• Pharmacology– Field of medicine that specializes in the study

of drugs, their sources, appearance, chemistry, actions, and uses

• Drug– Any substance that when taken into the body,

may modify one or more of its functions

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• Pharmacodynamics– Study of how drugs interact in the human

body

• Pharmacist– One who is licensed to prepare and dispense

drugs

Pharmacology Overview

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• Pharmacy– Drug store

• Toxicology– Study of poisons, their detection, their

effects– Establishing antidotes and methods of

treatment for conditions they produce

Pharmacology Overview

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Drug Laws

• Food, Drug, and Cosmetic Act (FDCA)– 1938– Regulates quality, purity, potency,

effectiveness, safety, labeling, and packaging of food, drug, and cosmetic products

– Enforced by the Food and Drug Administration (FDA)

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Drug Laws

• Controlled substance act– Regulates manufacture, distribution, and

dispensing and administration of controlled substances

• Drugs that have the potential of being abused and of causing physical or psychological dependence

– Enforced by the Drug Enforcement Administration (DEA)

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• Schedule I Drugs– Not considered to be legitimate for medical

use in the United States– Used for research only and cannot be

prescribed– High risk for abuse

• Examples: LSD, heroin, marijuana

Controlled Substances or Schedule Drugs

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• Schedule II Drugs– Accepted medical use but have a high

potential for abuse or addiction– Must be ordered by written prescription– Cannot be refilled without a new, written

prescription• Examples: morphine, cocaine, codeine, demerol,

dilaudid

Controlled Substances or Schedule Drugs

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• Schedule III Drugs– Moderate potential for abuse or addiction, low

potential for physical dependence– May be ordered by written prescription or by

telephone order– Prescription expires in six months – may not

be refilled more than five times in six-month period

• Examples: Tylenol with codeine, butisol, hycodan

Controlled Substances or Schedule Drugs

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• Schedule IV Drugs– Less potential for abuse or addiction than

those of Schedule III, with limited physical dependence

– May be ordered by written prescription or by telephone order

– May be refilled up to five times in a six-month period – prescription expires in six months

• Examples: Librium, valium, darvon, equanil

Controlled Substances or Schedule Drugs

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• Schedule V Drugs– Have a small potential for abuse or addiction– May be ordered by written prescription or by

telephone order– No limit on prescription refills– Some of these drugs may not need

prescription• Examples: Robitussin-AC, donnagel-PG, lomotil

Controlled Substances or Schedule Drugs

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Drug Standards

• Rules established to control strength, quality, and purity of medications prepared by various manufacturers– Require all preparations called by the

same drug name to be of a uniform strength, quality, and purity

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Drug Standards

• United States Pharmacopeia/National Formulary (USP/NF)– Contains formulas and information that

provide standards for preparation and dispensation of drugs

• Recognized by U.S. government as the official listing of standardized drugs in the United States

• FDCA specifies a drug is official when it is listed in USP/NF

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Drug References

• Available for health professionals responsible for safe administration of medications– Provide the following information:

• Composition, action, indications for use, contraindications for use, precautions, side effects, adverse reactions, route of administration, dosage range, and what forms are available

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Drug References

• Hospital formulary– Lists all drugs commonly stocked in the

hospital pharmacy– Provides information about the characteristics

of drugs and their clinical use

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Drug References

• Physicians’ Desk Reference– Published yearly by Medical Economics

Company– Manufacturers pay to list information about

their products in the PDR– Same information that appears on Package

Inserts (as required by the FDA)• Generic name, indications, contraindications,

adverse effects, dosage, and route of administration

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Drug References

• Medical economics company references– Physicians’ Desk Reference for

Nonprescription Drugs– Physicians’ Reference for Ophthalmology– Drug Interactions and Side Effects Index– Indications Index

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Drug References

• Drug facts and comparisons– Loose-leaf binder reference that provides

information on drugs according to their therapeutic classification

• Same basic facts as other drug references

– Particularly helpful in comparing the various drugs within each category to other products

• In reference to effectiveness, content, and cost

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Drug Sources

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Drug Names

• Chemical name– Describes chemical structure of the drug– Formula that indicates composition of the drug

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Drug Names

• Generic name– Name that was established when drug was

first manufactured• Written in lowercase letters

– Official name of a drug– Each drug has only one generic name– Original manufacturer is only company that

can use generic name for the first 17 years

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Drug Names

• Brand name– Name under which the drug is sold by a

specific manufacturer• Spelling always begins with a capital letter

– Also known as the Trade Name– Name is owned by the drug company and no

other company may use that name• Each brand name carries a registered trademark

symbol ®

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• Drug actions– How drugs produce changes within the body

• Drug effect– Changes that take place in the body as a

result of drug action• Slowing down or speeding up processes• Destroying certain cells or parts of cells• Replacing substances that the body lacks or fails

to produce

Drug Actions – Drug Interactions

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• Desired effect– Effect of drug in the body that was intended

• Side effect– Additional effect on the body by the drug that

was not part of the goal for that medication• Not usually severe enough to warrant

discontinuing the medication

Drug Actions – Drug Interactions

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• Adverse reaction– One in which the body reacts to a drug in an

unexpected way that may endanger a patient’s health and safety

• Contraindication– Any special symptom or circumstance that

indicates that the use of a particular drug or procedure is dangerous, not advised, or has not been proven safe for administration

Drug Actions – Drug Interactions

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• Local effect– Response to a medication that is confined to

a specific part of the body

• Systemic effect– Generalized or widespread response to a

drug by the body because it is absorbed into the bloodstream

Drug Actions – Drug Interactions

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• Cumulation– Occurs when a drug is not completely

excreted from the body before another dose is given

– Drug starts to accumulate in the body tissues when repeated doses are given

• Toxic effects may occur

Drug Actions – Drug Interactions

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• Idiosyncracy– An unusual, inappropriate response to a drug

or to the usual effective dose of a drug– Anaphylactic Shock = severe idiosyncratic

reaction• Acute respiratory distress, hypotension, edema,

tachycardia, cool pale skin, cyanosis, and possible convulsions shortly after administration of the medication

Drug Actions – Drug Interactions

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• Potentiation– Occurs when two drugs administered together

produce a more powerful response than the sum of their individual effects

• Tolerance– Resistance to effect of a drug

• A characteristic of drug addiction

Drug Actions – Drug Interactions

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Routes of Administration

• Oral– Given by mouth and swallowed– Advantage

• Easiest and safest method• Most economical method

– Disadvantage• Slow method of absorption• Possibility of being destroyed by gastric juices

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Routes of Administration

• Sublingual– Placed under the tongue – dissolves in saliva – Advantage

• More rapid absorption rate than oral• Higher concentration of medication reaches

bloodstream

– Disadvantage• Not convenient route of administration for bad-

tasting medications or irritating medications

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• Buccal– Placed in mouth next to cheek (tablet form)– Advantage

• More rapid absorption rate than oral• Higher concentration of medication reaches

bloodstream

– Disadvantage• Possibility of swallowing the pill

Routes of Administration

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• Inhalation– Medication is sprayed or inhaled into nose,

throat, and lungs– Advantage

• Good absorption due to large surface contact area• Provides rapid treatment

– Disadvantage• Sometimes difficult to regulate dose• Not suitable method for medications that irritate

mucous membrane lining

Routes of Administration

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• Rectal– Medication inserted into rectum and is slowly

absorbed into mucous membrane lining of rectum (suppository)

– Advantage• One method of choice when patient is nauseated or

cannot take medications orally

– Disadvantage• Absorption is slow and irregular

Routes of Administration

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• Vaginal– Medication is inserted into the vagina in the

form of a suppository, cream, foam, or tablet– Advantage

• Easiest method for treating the specific area

– Disadvantage• Medications sometimes stain underwear• No other disadvantages

Routes of Administration

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• Topical– Medication is applied directly to the skin or

mucous membrane for a local effect to area– Advantage

• Easy method, convenient

– Disadvantage• Slow absorption through skin

Routes of Administration

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• Transdermal– Method of applying a pre-measured amount of

medicine to unbroken skin through an adhesive-backed disk

– Advantage• Good method for administering medications slowly

into bloodstream over a period of time

– Disadvantage• Units can be dangerous if they come in contact

with skin of children or pets

Routes of Administration

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• Parenteral– Administered by injecting medication into

body using a needle and syringe– Must be in liquid form– Administered by one of following methods

• Intradermal• Intramuscular• Intravenous• Subcutaneous

Routes of Administration

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• Intradermal– Small amount of medication is injected just

beneath epidermis– Used for allergy testing, tuberculin skin

testing, and some vaccinations• Needle Angle: 10 to 15-degree

Routes of Administration

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• Intramuscular– Medication is injected directly into muscle– Used for administering antibiotics,

medications that might be irritating to layers of the skin, and medications that require dosages larger than amount allowed for subcutaneous injections

• Needle Angle: 90-degree

Routes of Administration

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• Intravenous– Medication is injected directly into the vein,

entering the bloodstream immediately– Used when medication is needed quickly– Used for infusing medication over a period of

time, by adding the medication to a bag of intravenous fluids

• Needle Angle: 25-degree

Routes of Administration

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• Subcutaneous– Medication is injected into subcutaneous

layer, or fatty tissue of skin– Used for administering insulin, hormones, and

local anesthetics• Needle Angle: 45-degree

Routes of Administration

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Parenteral Routes of Administration

DRUG CLASSIFICATIONS

Pharmacology

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Analgesic

• Pronounced

– (an-al-JEE-sik)

• General definition– Relieves pain

• Example: acetylsalicylic acid, aspirin, Bayer Children’s Aspirin

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Anesthetic

• Pronounced– (an-ess-THET-ik)

• General definition– Partially or completely numbs or eliminates

sensitivity with or without loss of consciousness

• Example: lidocaine (Xylocaine)

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Antiarrhythmic

• Pronounced– (an-tee-ah-RITH-mik)

• General definition– Corrects cardiac arrhythmias (irregular beats)

• Example: digoxin (Lanoxin)

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Antibiotic(Anti-infective)

• Pronounced– (an-tih-BYE-ot-ik)

• General definition– Stops or controls growth of infection-causing

microorganisms• Example: phenoxymethyl-penicillin sodium (Pen-

Vee-K, Penicillin VK, Veetids, V-Cillin K)

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Anticoagulant

• Pronounced– (an-ti-koh-AG-yoo-lant)

• General definition– Prevents clot continuation and formation

• Example: warfarin sodium (Coumadin)

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Anticonvulsant

• Pronounced– (an-tih-kon-VULL-sant)

• General definition– Prevents or relieves convulsions (seizures)

• Example: clonazepam (Klonopin)

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Antidepressant

• Pronounced– (an-tih-dee-PRESS-ant)

• General definition– Prevents, cures, or alleviates mental

depression• Example: amitriptyline hydrochloride (Elavil,

Amitril)

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Antidiabetic

• Pronounced– (an-tih-dye-ah-BET-ik)

• General definition– Helps control the blood sugar level

• Example: metformin (Glucophage)

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Antidiarrheal

• Pronounced– (an-tih-dye-ah-REE-ul)

• General definition– Prevents or treats diarrhea

• Example: loperamide hydrochloride (Imodium)

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Antidiuretic

• Pronounced– (an-tih-dye-yoo-REH-tic)

• General definition– Suppresses the formation of urine

• Example: vasopressin (Pitressin)

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Antiemetic

• Pronounced– (an-tih-ee-MET-ik)

• General definition– Prevents or relieves nausea and vomiting

• Example: meclizine hydrochloride (Bonine, Dramamine II, Antivert)

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Antifungal

• Pronounced– (an-tih-FUNG-gal)

• General definition– Destroys or inhibits the growth of fungi

• Example: fluconazole (Diflucan)

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Antihistamine

• Pronounced – (an-tih-HISS-tah-meen)

• General definition– Opposes action of histamine, released in

allergic reactions• Example: cetirizine (Zyrtec)

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Antihypertensive

• Pronounced– (an-tih-high-per-TEN-siv)

• General definition– Prevents or controls high blood pressure

• Example: nadolol (Corgard)

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Anti-infective(Antibiotic)

• Pronounced– (an-tih-in-FEK-tiv)

• General definition– Stops or controls the growth of infection-

causing microorganisms• Example: amoxycillin (Amoxil, Polymox)

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Anti-Inflammatory

• Pronounced– (an-tih-in-FLAM-ah-toh-ree)

• General definition– Counteracts inflammation in body

• Example: naproxen sodium (Anaprox, Aleve)

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Antineoplastic

• Pronounced– (an-tih-nee-oh-PLASS-tik)

• General definition– Prevents development, growth, or

reproduction of cancerous cells• Example: fluorouracil (Adrucil)

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Antitussive

• Pronounced– (an-tih-TUSS-iv)

• General definition– Relieves cough due to various causes

• Example: dextromethorphan hydrobromide (Benylin DM, Robitussin Pediatric, Vick’s Formula 44)

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Antiulcer Agent

• Pronounced– (an-tih-ULL-ser agent)

• General definition– Treats and prevents peptic ulcer and gastric

hypersecretion• Example: ranitidine hydrochloride (Zantac)

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Antiviral Agent

• Pronounced– (an-tih-VYE-ral agent)

• General definition– Treats various viral conditions such as serious

herpes virus infections, chickenpox, and influenza A

• Example: acyclovir (Zovirax)

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Beta Blocker

• Pronounced– (BAY-tah BLOCK-er)

• General definition– Treats hypertension, angina, and various

abnormal heart rhythms• Example: metoprolol tartrate (Lopressor)

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Bronchodilator

• Pronounced– (brong-koh-DYE-lay-tor)

• General definition– Expands bronchial tubes by relaxing bronchial

muscles• Example: theophylline (Bronkodyl)

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Calcium Channel Blocker

• Pronounced– (KAL-see-um CHAN-ell BLOCK-er)

• General definition– Treats hypertension, angina, and various

abnormal heart rhythms• Example: amlodipine (Norvasc)

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Diuretic

• Pronounced– (dye-yoor-RET-ik)

• General definition– Increases urine secretion

• Example: furosemide (Lasix)

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Hormone

• Pronounced– (HOR-mohn)

• General definition– Treats deficiency states where specific

hormone level is abnormally low• Example: estrogen, conjugated (Premarin)

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Hypnotic

• Pronounced– (hip-NOT-ik)

• General definition– Induces sleep or dulls the senses

• Example: pentobarbital (Nembutal)

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Immunosuppressant

• Pronounced– (im-yoo-noh-suh-PRESS-ant)

• General definition– Suppresses the body’s natural immune

response to an antigen, as in treatment for transplant patients

• Example: cyclosporine (Sandimmune)

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Laxative

• Pronounced– (LACK-sah-tiv)

• General definition– Prevents constipation or promotes the

emptying of the bowel contents with ease• Example: docusate calcium (Surfak)

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Lipid-Lowering Agent

• Pronounced– (LIP-id lowering agent)

• General definition– Reduces blood lipid (fat) levels

• Example: atorvastatin (Lipitor)

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Sedative

• Pronounced– (SED-ah-tiv)

• General definition– Exerts a soothing or tranquilizing effect on the

body• Example: phenobarbital (Nembutal)

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Skeletal Muscle Relaxant

• Pronounced– (SKELL-eh-tal muscle rih-LAK-sant)

• General definition– Relieves muscle tension

• Example: carisoprodol (Soma)

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Vitamin

• Pronounced– (VIGH-tah-min)

• General definition– Prevents and treats vitamin deficiencies and

used as dietary supplement• Example: ascorbic acid (vitamin C)

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• Guidelines– Medical abbreviations are a form of shorthand

• Serve as a universal language for medical professionals

• Provide specific information and/or orders in an abbreviated format

– Health professional should use standard abbreviations accepted by their place of employment

• When abbreviations have more than one meaning

Common Charting Abbreviations