PHARMACOLOGY

PHARMACOLOGY

2011

Intro to Pharmacology

 Welcome to Pharmacology

 Pharmacology means “medicine” and “study”

essentially the study of medicine

 Pharmacology is a discipline devoted to patient

therapy though the use of drugs. It is an expansive

topic utilizing concepts from human biology,

pathophysiology, and chemistry.

pharmacology and therapeutics

 Therapeutics is the discipline dealing with the

treatment of suffering and the prevention of

disease.



 Pharmacotherapeutics is the useful application of

drugs for the purpose of fighting disease.



 Both areas are at the core of the nursing profession.

 Therapeutic agents may be classified as traditional

drugs, biologics or alternative therapies.



 Drugs are chemical agents used to treat diseases in the

body. Biologic drugs are substances produced naturally

by a living organism.



 Alternative therapies involve herbal supplements and

certain techniques deemed to be less conventional.

RX vs OTC

 Drugs are available by prescription or as over the

counter (OTC) medication.



 There are two major methods of dispensing drugs:

purchase of prescriptions drugs with a physician’s

order and purchase of OTC drugs which do not

require a physician’s order.



 There are advantages and disadvantages to both

methods of dispensing.

FDA

 Food and Drug Administration (FDA) was an agency

established by the U.S. Department of Health and

Human Services to help regulate over prescription

drugs, OTC drugs, as well as medical devices.



 Drug approval involves four stages: pre-clinical

investigation, clinical investigation, submission of a New

Drug Application with review, and post-marketing

surveillance. Clinical phase trials must be completed

before drugs are approved for public use.

Drug Classes and Schedules

 Drugs may be organized by their therapeutic or

pharmacologic classification.



 Two common ways to classify drugs are by therapeutic

classification and pharmacological classification.

 Therapeutic classes are based on a drug’s clinical

usefulness.

 Pharmacological classes are based on a drug’s mechanism

of action.

 Prototype drugs are used to compare drugs within the same

classification.

chemical, generic, and trade names



 Drugs may be described by a chemical, generic or

trade name.

 Chemical names are precise but complicated and

difficult to remember. Drugs have only one generic

name that is usually short and easy to remember.

The company marketing the drug assigns trade

names. Drugs may have multiple trade names.

Generic and Brand name

 Generic drugs are less expensive than brand name

drugs, but they may differ in their bioavailability.

 Generic drugs are less expensive and may be

substituted for brand named products in most states

if the prescriber does not object. Generic drugs

may differ from their trade name counterparts with

respect to their bioavailability. This may affect the

safety and effectiveness of drug therapy.

Controlled Substances

 Scheduled Drugs

I High Abuse Potential

High Physical Dependence

High Psychological Dependence

Heroin, LSD, Marijuana

II ex. Morphine, PCP, cocaine, methadone

used therapeutically with prescription

Controlled Substances

• Scheduled Drugs

III Moderate Abuse Potential

Moderate Physical Dependence

High Physiological Dependence

ex. Anabolic steroids, codeine,

hydrocodone, some barbituates

IV Lower/Lower/Lower

V Lowest/Lowest/Lowest

ex. OTC cough medicines with codeine

Principles of Drug Administration



 Allergic Reaction: acquired hyperresonance of body

defenses to a foreign substance (allergen).

 Anaphylaxis: severe type of allergic reaction that

involves the massive, systemic release of histamine

and other chemical mediators of inflammation that

can lead to life-threatening shock.

 Side Effects vs Adverse Effects

Fatal Drug Reactions

 Toxic Epidermal Necrolysis (TEN)

 Widespread epidermal sloughing

 Epidermal detachment of skin and mucous membranes



 Multisystem organ involvement



 Assoc. with anticonvulsants, Abs, and other drugs

 dilantin, carbamazepine, Bactrim

Fatal Drug Reactions

 Stevens-Johnson Syndrome

 Causes similar to those that cause TEN

 Begins within the first 1-14 days of pharmacotherapy



 Starts as signs of URI with chills, fever and malaise



 Generalized blisterlike lesions follow within a few days



 Skin sloughing of 10% of the body

Three Checks – Safety First

• Three checks of drug administration:

– Checking the drug with MAR or the medication

information system when removing it from the

medication drawer, refrigerator or controlled substance

locker.

– Checking the drug when preparing it, pouring it, taking

it out of the unit-dose container, or connecting the IV

tubing to the bag.

– Checking the drug before administering to the client.

Five Rights of Drug Adminstration



 Right client (2 patient identifiers)

 Right medication

 Right dose

 Right route of administration

 Right time of Delivery

 Bonus:

 Right Allergy

Principles of Drug Administration



 The nurse must have a comprehensive knowledge of

the actions and side effects of drugs before they

are administered.

 The nurse assumes great responsibility for drug

administration.

 A firm knowledge of pharmacology is required

before a drug is administered. This understanding

takes into account the actions and side effects of the

drug as well as the physical and emotional needs of

each patient.

Compliance/Orders

 Compliance: taking medication in the manner

prescribed by the practitioner, or in the case of OTC

drugs, following the instructions on the label.

 STAT order: Refers to any medication that is needed

immediately.

 ASAP: Available within 30 minutes

Compliance

 For pharmacologic compliance, the patient must understand

and personally accept the value associated with the

prescribed drug regimen. Understanding the reasons for

noncompliance can help the nurse increase the success of

pharmacotherapy.

 The nurse may be conscientious regarding all of the

principles of medication administration but these strategies

are of little value unless the patient agrees that the

prescribed medication regimen is personally worthwhile. The

nurse must understand factors which decrease compliance

such as expense, annoying side effects, and self-dosing with

the medication.

Medication Orders

 Single Order: Only once

 PRN: As needed basis

 Routine orders: carried out within two hours of the

time it is ordered by the physician.

 Standing order: Written in advance of a situation

that is carried out under specific circumstances.

 Ex. Tylenol 325 mg PO Q 6hrs PRN headache

Systems of Measurement

 Systems of measurement used in pharmacology include

the metric, apothecary, and household systems.

 Doses are usually written in terms of the metric system

such as milligrams or milliliters. The older apothecary

system is rarely used. The household system (which

employs the teaspoon and tablespoon method) remains

in common use. Therefore, the nurse must be able to

convert between the apothecary and metric systems.

Administering Drugs

 Routes

 Parental Drug Administration

 Enteral Drug Administration

 Transdermal, opthalmic

 Topical Drug Administration

 Otic, nasal, vaginal, rectal

Key Points

• Must have a comprehensive knowledge of the

actions and side effects of drugs before they are

administered to limit the number and severity of

adverse drug events.

• The 5 rights and 3 checks are guidelines for safe

drug administration which is a collaborative effort

between nurses, physicians, and other healthcare

professionals.

Enteral Route

• The enteral route includes medications given orally and

those administered through nasogastric or gastrostomy

tubes.



• Oral medication administration through tablet, capsule,

and liquid formulation is the most common, convenient,

and usually, the least costly of all the routes. Absorption

is generally slow and the drug must be stable in the

presence of digestive enzymes. The sublingual and

buccal routes are enteral routes less commonly used.

Topical Drugs

• Topical drugs are applied locally to the skin or

membranous linings of the eye, ear, nose respiratory

tract, urinary tract, vagina and rectum.



 Topical medications may be applied for either topical

or systemic effects. Most topical routes provide for slow

absorption, thus they produce few systemic side effects.

Topical routes include dermatologic, instillation, and

inhalation.

Parenteral

 Parental administration is the dispensing of medications via a

needle, usually into the skin layers (ID), subcutaneous (SQ),

intramuscularly (IM), and into veins (IV).



 Parenteral administration results in a rapid onset of drug action.

Because of the possibility of introducing microbes directly into the

body, parenteral routes are considered invasive and require aseptic

technique. Parenteral administration includes the ID, SC, IM, and IV

routes.



Pharmacokinetics

 Pharmacokinetics focuses on the movement of drugs

throughout the body after they are administered.



 Pharmacokinetics is an area of pharmacology dealing

with how drugs are handled by the body. It describes

the barriers that drugs must penetrate to achieve

therapeutic success. The four components of

pharmacokinetics are: absorption, distribution,

metabolism, and excretion.

Pharmacokinetics

 The physiological properties of plasma membranes

determine movement of drugs throughout the body.



 To be distributed to body tissues, drugs use diffusion

and active transport to cross biological membranes.

Drugs that are small, uncharged, and lipid soluble

are distributed more completely than those that are

large, ionized, and water-soluble.

Absorption and its rate

 Absorption is the process of moving a drug from the

site of administration to the bloodstream.

 Many factors affect drug movement including the

type of drug formulation, drug-drug and drug-food

interaction, GI and bloodstream factors, and

properties of cellular membranes. Lipid solubility,

ionization characteristics, and the pH of the

dissolving or transport medium will also affect drug

absorption.

Distribution

 Distribution: involves the transport of pharmacologic

agents throughout the body>

 The determining factor is the distribution of the

amount of blood flow to the body tissues.

 The heart, liver, kidneys and brain receive the most

blood supply.

 Blood Brain Barrier

 Fetal-Placental Barrier

Distribution

 A drug’s distribution is affected by variables such as

lipid solubility, degree of ionization, and plasma

protein binding.



 The blood-brain and fetal-placental barriers represent

areas in the body where drug distribution may be

limited.



 Lipid-soluble and non- ionized drugs easily cross these

barriers; water-soluble and ionized drugs do not.

Excretion

 Excretion processes remove drugs from the body.

 The kidneys, lungs, sweat glands, mammary glands,

and biliary system are the major tissues eliminating

drugs from the body.

 The main organ involved with excretion is the

kidney.

 Enterohepatic recirculation is responsible for

circulating bile and certain drugs back into the

bloodstream from the gastrointestinal tract.

Excretion

• Rate at which drugs are excreted determines their

concentration in the bloodstream and tissues.

• The concentration of the drugs in the bloodstream

determines the duration of action.

• Pathological states such as liver disease and renal

failure often increase the duration of action in the

body because they interfere with the natural

excretion mechanisms.

– Dosing must be adjusted in these cases

Pharmacodynamics

 Pharmacodynamics is the area of pharmacology

concerned with how drugs produce change in

patients and the differences in patient responses to

medications.



 Pharmacodynamics explains how drugs produce

changes in the body.

Therapeutic and Toxic Range

• Minimum Effective Concentration

– The amount of drug required to produce a therapeutic

effect

• Toxic Concentration

– The level of the drug that will result in serious adverse

effects

• Therapeutic range

– Plasma drug concentration between the minimum

effective concentration and the toxic concentration

Therapeutic Index

 The therapeutic index is a value representing the

margin of safety of a drug.



 The larger a medication’s therapeutic index, the

greater is its margin of safety.

Pharmacokinetics

• Maintenance dose

– Dose given to keep the plasma drug concentration in the

therapeutic range

• Loading dose

– A higher concentration of medication given to prime the

blood stream with levels significant to quickly induce a

therapeutic response.

• Half-life

– Length of time required for the plasma concentration of a

medication to decrease by half after administration.

Comparing Drugs

 Efficacy

 Magnitude of maximal response that can be produced

from a particular drug.

 Potency

A drug that is more potent will produce a therapeutic

effect at a lower dose, compared with another drug in

the same class.

Aspirin 650 mg versus Ibuprofen 200 mg

Ibuprofen more potent, same efficacy

Potency vs Efficacy

 Potency relates to the dose of medication required

to produce a particular response; the higher the

potency, the less dose is needed to produce a

response.



 Efficacy refers to the magnitude of maximal

response: the higher the efficacy, the greater the

response. In most cases, the efficacy of a drug is

more important to the patient and nurse than is the

potency.

Drug Administration Throughout the

Lifespan

 In order to contribute to safe and effective

pharmacotherapy, it is essential for the nurse to

comprehend and apply fundamental concepts of

growth and development.

 Nurses must possess an understanding of what is

considered normal, in terms of growth and

developmental patterns, so that deviations from the

norm can be identified and health pattern impairments

can be appropriately addressed. The very nature of

pharmacology requires that the practitioner consider

the specifics of age, growth, development, and weight

in relation to pharmacokinetics and pharmacodynamics.

Pregnancy

 Pharmacotherapy during pregnancy should be

conducted only when the benefits to the mother

outweigh the potential risks to the fetus.



 Pregnancy Categories guide the practitioner in

prescribing drugs for these patients.



 Breastfeeding patients must be aware that drugs and

other substances can appear in milk and affect their

infant.

Pregnancy

 Chemicals derived from foods and drugs ingested by

the mother may traverse the placental barrier and

affect the developing baby.

 An in-depth nursing and pharmacologic history and

prenatal assessment are vital so that drugs can be

eliminated, substituted or dosages adjusted.

 Pregnancy Categories have been developed by the

FDA to assess potential risk to the fetus. Breast-feeding

patients must be aware that drugs and other substances

can appear in milk and affect their infant.

Pregnant Client

• Pregnant client

– Distribution and Metabolism

• Increase Cardiac Output

• Increased Blood Flow

• Change in regional blood flow

• Alterations in lipid levels

– Absorption

• Hormonal changes, pressure on blood supply

• Gastric emptying delayed

• Gastric acidity decreased

• Increased Resp. system

Pregnant Client – Teratogenic effects



 Pregnant client

 Excretion

 Increased kidney flow by 40%



Teratogens-agents that cause fetal malformation

Especially in the first trimester



Lactating Client-many OTC, herbal supplements and meds are

excreted in the breast milk

Infants

 During infancy, pharmacotherapy is directed toward the

safety of the child and teaching the mother how to

properly administer medications and care for the infant.



 Infants require special treatment due to their small size

and their immature physiologic and biochemical

processes.



 Mothers breastfeeding their infants must be counseled

regarding the possibility of drugs entering their milk

and affecting their baby.

Toddlers

 Drug administration to toddlers can be challenging.



 Short, concrete explanations followed by immediate drug

administration are usually best for the toddler.



 During the toddler stage, there is a tremendous sense of

curiosity and this becomes a major concern for medication

safety as well as household product safety. Toddlers can

swallow liquids and usually chew tablets. Restraint may be

required, particularly when administering parenteral

medications.

Preschoolers and younger school age



 Preschool and younger school age children can begin to

assist with medication administration.



 During the early school years, children begin to realize

the benefits of medications and the reasons why

medications are needed.



 The nurse should give the child a sense of control over

drug administration, while still being firm and giving the

child praise for cooperation.

Adolescents

 Pharmacologic compliance in the adolescent is dependent

upon an understanding and respect for the uniqueness of the

person in this stage of growth and development.



 Adolescents are very concerned with physical appearance

and peer approval. Common indications for

pharmacotherapy in this group includes: skin conditions,

headaches, menstrual irregularities, and sports injuries. The

use of tobacco and illicit drugs is a major concern. The nurse

should respect a teen’s need for independence and privacy.

Young Adults

 Young adults comprise the healthiest age group and

generally need few prescription medications.

 Middle age adults begin to suffer from stress-related

illness such as hypertension.

 Younger and middle-aged adults generally need little

pharmacotherapy, relative to older adults.

 In females, contraception and complications associated

with pregnancy are of major concern.

 In the middle-aged adult, cardiovascular concerns such

as hypertension become important.

Older Adults

 Older adults take more medications and experience more adverse

drug events than any other age group. For drug therapy to be

successful, the nurse must make accommodations for age-related

changes in physiological and biochemical functions.

 The older adult is faced with numerous physical challenges, which

become targets for pharmacotherapy. Changes in liver and kidney

function make pharmacotherapy more risky. Cardiovascular disease

becomes a major indication for pharmacotherapy.

Elderly and Medication Use

 Monitor for nutritional status and hydration

 Liver and Kidney Function

 Polypharmacy

 Safety First

 Compliance

 Reinforce

Herbal and Alternative Therapies



• Familiarize yourself with the Best-Selling Herbal

Supplements pg 110

• Familiriaze yourself with the most Common Herb

Drug Interactions pg 113

– Garlic

– Ginger

– Ginko

– Ginseng

– Kava Kava

– St. John’s Wort

Nursing Process and Pharmacology

 The Nursing Process is a systematic method of problem-

solving and consists of clearly defined steps:

assessment, establishment of nursing diagnoses,

planning care through the formulation of goals and

outcomes, carrying out interventions, and evaluating the

care provided.

 The steps of the nursing process include assessment,

development of nursing diagnoses, identification of

goals and outcomes, planning care, implementing

interventions and evaluating the plan of care.

Pharmacology requires the use of the Nursing Process to

ensure the best possible outcomes for the patient.

Assessment

 Assessment of the patient related to medication

administration includes health history information,

physical assessment data, lab values and other

measurable data. It also includes an assessment of

medication effects: therapeutic, side or adverse

effects.

 Assessment is the collection of objective and

subjective data. This is acquired starting with the

initial health history and continues on an ongoing

basis during treatment.

Nursing Diagnosis

 Nursing diagnoses are written that address the patient’s

responses related to medication administration. They are

developed after an analysis of the assessment data. The

diagnoses are focused on the patient’s problems or potential

problems and are verified with the patient or caregiver.

 After analyzing the assessment data, the nurse formulates

patient-specific nursing diagnoses appropriate for the

medications used. These diagnoses will form the basis for the

other steps in the Nursing Process. Two of the most common

nursing diagnoses that may be established for medication

administration are knowledge deficit and noncompliance.

Goals

 Goals and outcomes are developed from the nursing

diagnoses that will direct the interventions required by the

plan of care. Goals focus on what the patient should be

able to achieve and outcomes provide the specific,

measurable criteria that nurses will use to measure goal

attainment.

 After gathering patient assessment data and formulating

nursing diagnoses, goals and outcomes are developed and

priorities are established that will assist the nurse in planning

care, carrying out interventions, and evaluating the

effectiveness of that care. Goals and outcomes may be

developed for the short-term or long-term, depending on

the specific situation.

Interventions

 Interventions are aimed at returning the patient to an

optimum level of wellness through the safe and

effective administration of medications. Key

interventions required of the nurse include monitoring

drug effects, documenting medications, and patient

education.

 Interventions are aimed at returning the patient to an

optimum level of wellness and limiting adverse effects

related to the patient’s condition. Key components of

implementation include monitoring and documentation

of drug effects, and patient education.

Evaluation

 Evaluation begins a new cycle as new assessment

data is gathered and analyzed, nursing diagnoses

are reviewed or rewritten, goals and outcomes

refined, and new interventions are implemented.



 Evaluation is the final step of the Nursing Process. It

considers the effectiveness of the plan of care and

interventions in meeting established goals and

outcomes.

Legal and Ethical Issues

 The American Nurses Association publishes a list of

ethical principles that nurses can use to guide their

decision making.



 Ethics (the moral principles guiding a person’s

conduct) are learned early in life through religious

affiliations, family, role models, and peers. The ANA

Code of Ethics provides guidance to nurses in their

professional conduct and in decision- making.

Legal and Ethical Issues

 Moral principles such as beneficence, non-maleficent

behavior, veracity, autonomy, justice, and fidelity are

necessary for the nurse to apply in medication

administration.

 When making ethical decisions in clinical practice, the

nurse uses fundamental moral principles. Three of the

most important principles are: promote the most good

for the patient (beneficence), do not harm the patient

(non-maleficent behavior), and allowing the patient the

informed right to choose the course of their care

(autonomy).

Legal and Ethical Issues

 Nurse practice acts are enacted by every state to

define the scope of practice of professional nursing

and to protect the public.

 The State nursing practice acts define the standard

of care for practicing nurses. In essence, they define

what a nurse can and cannot do. Standards of care

state the minimum competency for proficiency in

nursing and should be consulted frequently.

Legal and Ethical Issues

 Documentation of medication administration,

including any errors, should be completed

immediately after the patient takes the drug.



 Medication use is documented in the MAR. Nurses

frequently check the physician’s orders against the

MAR to be certain the correct drugs have been

administered.

medication error

 A medication error is a preventable error that may

cause or lead to an adverse reaction to the patient.

Causes may include omission of one of the “five

rights” or giving medications based on verbal,

illegible or incomplete orders.

 Medication errors can result in serious injury to the

patient and litigation for the nurse and healthcare

agency. The nurse must ensure that orders are

carried out accurately and that every measure is

taken to avoid errors.

medication error

 It is the ethical and legal responsibility of the nurse to report any

medication errors that might have occurred.



 Documentation of medication errors is necessary for patient safety.

Several national organizations contain databases of medication

errors that can assist nurses and healthcare agencies formulate

better policies.



 9.7 Finding strategies to prevent of medication errors involves many

different processes, including the nursing process.

Medication Error

 Use of the nursing process can help reduce the

number of medication errors. Nurses should work

and collaborate with others on the healthcare team

to develop agency policies for the storage and

handling of medicines.