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Introduction to Nursing Pharmacology Nursing Pharmacology

Drug Therapy in the 21st Century

Drug Therapy in the 21st Century

Changes in Health Care in the 21st Century

  • Access to medical and pharmacologic information is available from many sources
  • Consumers are taking steps to demand specific treatments and considerations
  • Alternative therapies are being offered and advertised
  • Financial pressures are leading to early discharge
  • Patient teaching and home care provisions are vital

Federal Guidelines—Drug Advertising

  • When the advertisement states the indication, it must also include:
    • Contraindications
    • Adverse effects
    • Precautions

Internet Sources for Drug Information

  • Pharmaceutical company information sites
  • Chat rooms with other people who are taking the drug
  • Online pharmacies
  • Lists of government regulations
  • Research reports about the drug and its effectiveness

Internet Site Evaluation

  • Navigation
    • Is the site easy to access and navigate or confusing?
  • Contributor
    • Who prepared the site and what are his qualifications? Is it reviewed, or is it purely commercial?
  • Dates
    • Is the site updated frequently?
  • Accuracy/reliability
    • Is the information supported by other sites, accurate, and in agreement with other sources you have reviewed? Are other links listed?

Problems Associated With OTC Medications

  • Can mask the signs and symptoms of disease
  • Can interact with prescription drugs
  • Can be taken in greater than the recommended dose, leading to toxicity

Over-the-Counter Drugs

  • Drugs that were “grandfathered” in
  • Former prescription drugs that have been tested and found to be safe for the general public if used as directed

Alternative Therapy Drawbacks

  • The active ingredient has not been tested by the FDA
  • Incidental ingredients are unknown
  • Patients do not always mention these therapies to their health care providers
  • Drug–alternative therapy interactions may occur

Controls for Alternative Therapy

  • Herbal medications and alternative therapies are not controlled or tested by the FDA
  • Advertisement for these drugs is not restricted because they are considered dietary supplements
  • No regulation by any industry

Off-Label Medications

  • Definition
    • The use of a drug for an indication that is not approved by the FDA
  • Occurrence
    • Commonly takes place in groups of patients for whom there is little premarketing testing
    • Used with pediatric and geriatric populations

Health Care in Crisis

  • Skyrocketing cost of medical care and drugs
  • Huge research and equipment requirements to meet consumer demands
  • Rising cost of health insurance
  • Earlier discharge from hospitals

Measures to Protect the Public From Bioterrorism

  • Emergency preparedness at all levels of the government

Treatments for Exposure to Biological/Chemical Weapons

Recommended Treatments for Biological/Chemical Weapons Exposure
Recommended Treatments for Biological/Chemical Weapons Exposure
Recommended Treatments for Biological/Chemical Weapons Exposure
Recommended Treatments for Biological/Chemical Weapons Exposure
Categories
Introduction to Nursing Pharmacology Nursing Pharmacology

Dosage Calculation

Dosage Calculations

Dosing Considerations

  • Sex
  • Weight
  • Age
  • Physical condition
  • Other drugs that the patient is taking

Accurate Dosing

  • Dependent on:
    • The prescriber who orders the drug
    • The pharmacist who dispenses the drug
    • The nurse who administers the drug

Measuring Systems

  • Metric system
  • Apothecary system
  • Household system
  • Avoirdupois system

Metric System

  • Solids: gram (g)
    • 1 milligram (mg) = 0.001 g
    • 1 microgram (mcg) = 0.000001 g
    • 1 kilogram (kg) = 1000 g
  • Liquids: liter (L)
    • 1 milliliter (mL) = 0.001 L
    • 1 mL = 1 cubic centimeter = 1 cc

Apothecary System

  • Solids: grain (gr)
    • 60 gr = 1 dram (dr)
    • 8 dr = 1 ounce (oz)
  • Liquids: minim (min)
    • 60 minim = 1 fluidram (f dr)
    • 8 f dr = 1 fluidounce (f oz)

Household System

  • Solids: pound (lb)
    • 1 lb = 16 ounces (oz)
  • Liquids: pint (pt)
    • 2 pt = 1 quart (qt)
    • 4 qt = 1 gallon (gal)
    • 16 oz = 1 pt = 2 cups (c)
    • 32 tablespoons (tbsp) = 1 pt
    • 3 teaspoons (tsp) = 1 tbsp
    • 60 drops (gtt) = 1 tsp

Conversion Table

Commonly Accepted Conversion Between Systems of Measurement
Commonly Accepted Conversion Between Systems of Measurement

Conversion Between Systems

amount of drug available amount of drug prescribed
one tablet or capsule #           of tablets or capsules to give

amount of drug availableamount of drug prescribed
volume available                       volume to administer

Solving for X

amount of drug available =   amount of drug prescribed
one tablet or capsule           # of tablets or capsules to give

10 mg = 40 mg
1                x

Examples

1 oz =   6 oz
30 mL        X

1 oz x X = 6 oz x 30 mL
1(oz)X = 180 (oz) (mL)

X = 180 (oz) (mL)
1 oz
X = 180 mL

Calculating IV Drip Rate

drops/min = mL of solution prescribed per hr x drops delivered per mL
60 min/hr

Difference Between Children and Adults

  • Children absorb, distribute, metabolize, and excrete drugs differently than adults
  • Children’s organs are not as developed as adults’ organs

Pediatric Dosage Calculation

  • Fried’s rule
  • Young’s rule
  • Clark’s rule
  • Surface area calculation

Fried’s Rule

This rule assumes that an adult dose would be appropriate for a child who is 12.5 years (150 months) of age

child’s dose (age <1 year) =   infant’s age (in months)
150 months x average adult dose

Young’s Rule

child’s dose (age 1 to 12 years)  =

child’s age in years
child’s age in years + 12 x average adult dose

Clark’s Rule

Uses the child’s weight to calculate the appropriate dose and assumes the adult dose is based on a 150-lb person

child’s dose  =   weight of child in pounds
150 pounds x average adult dose

Surface Area Calculation

  • Determine the child’s surface area with the use of a nomogram (the height and weight of the child are taken into consideration in this chart)

child’s dose = surface area in square meters
1.73 x average adult dose

Nomogram

Nomogram
Nomogram
Categories
Introduction to Nursing Pharmacology Nursing Pharmacology

Toxic Effects of Drugs

Toxic Effects of Drugs

Adverse Drug Reaction

  • Definition
    • Adverse effects are undesired effects that may be unpleasant or even dangerous
  • Reasons adverse drug reactions occur:
    • The drug may have other effects on the body besides the therapeutic effect
    • The patient is sensitive to the drug given
    • The drug’s action on the body causes other responses
    • The patient is taking too much or too little of the drug

Types of Adverse Reactions

  • Primary actions
    • Overdose: extension of the desired effect
  • Secondary actions
    • Undesired effects produced in addition to the pharmacologic effect
  • Hypersensitivity reactions
    • Excessive response to the primary or secondary effect of the drug

Types of Drug Allergies

  • Anaphylactic reaction
  • Cytotoxic reaction
  • Serum sickness reaction
  • Delayed allergic reaction

Variety of Adverse Effects Associated With Drug Use

Types of Drugs Allergies
Types of Drugs Allergies

Drug-Induced Tissue & Organ Damage

Drug-Induced Tissue and Organ Damage
Drug-Induced Tissue and Organ Damage

Dermatologic Reactions

  • Rash/hives
    • Assessment
      • Abnormalities in the skin, red areas, blisters
    • Interventions
      • May need to discontinue the medication
  • Stomatitis
    • Assessment
      • Inflammation of the mucous membranes
    • Interventions
      • Frequent mouth care

Drug-Induced Tissue and Organ Damage

  • Superinfections: destruction of the body’s normal flora
    • Assessment
      • Fever, diarrhea, and vaginal discharge
    • Interventions
      • Supportive care (mouth/skin care), give antifungal medications, stop drug responsible for the infection
  • Blood dyscrasia: bone marrow suppression
    • Assessment
      • Fever, chills, and weakness
    • Interventions
      • Monitor blood counts and protective isolation

Toxicity

  • Liver
    • Assessment
      • Fever, nausea, jaundice, change in color of urine or stool, and elevated liver enzymes
    • Interventions
      • Discontinue medication
  • Kidney
    • Assessment
      • Change in urinary pattern or elevated BUN and creatinine
    • Interventions
      • Notify physician, stop medication, or decrease dosage

Poisoning

  • Poisoning occurs when an overdose of a drug damages multiple body systems
  • Damage to multiple systems can lead to a fatal reaction

Altered Glucose Metabolism

  • Hypoglycemia
    • Assessment finding: low serum blood glucose level
    • Intervention: restore glucose to the body (D50)
  • Hyperglycemia
    • Assessment finding: high serum glucose level
    • Intervention: administer medications to decrease glucose level (insulin)

Electrolyte Imbalances

  • Hypokalemia
    • Assessment finding: decrease in serum potassium level
    • Interventions: replace serum potassium (IV or oral supplement) and monitor serum level of potassium
  • Hyperkalemia
    • Assessment finding: increase in serum potassium level
    • Interventions: decrease the serum potassium concentration (using sodium polystyrene sulfonate), monitor serum level of potassium, and monitor cardiac rhythm

Sensory Effects

  • Ocular toxicity
    • Assessment finding: visual changes
    • Interventions: monitor for visual changes when giving medication known to cause ocular damage; discontinue medication after notifying physician
  • Auditory damage
    • Assessment finding: damage to the eighth cranial nerve
    • Interventions: monitor for hearing loss; discontinue medication after notifying physician

Neurologic Effects

  • General central nervous system (CNS) effects
    • Assessment: altered level of consciousness
    • Intervention: prevent injury
  • Atropine-like (anticholinergic) effects
    • Assessment: dry mouth, urinary retention, and blurred vision
    • Interventions: sugarless lozenges to keep mouth moist; advise the patient to void before administration of the medication
  • Parkinson-like syndrome
    • Assessment: muscle tremors and changes in gait
    • Intervention: discontinue medication
  • Neuroleptic malignant syndrome
    • Assessment: extrapyramidal symptoms
    • Intervention: discontinue medication

Teratogenicity

  • Drugs may harm the developing fetus or embryo
  • Prevent teratogenicity through teaching
    • Advise pregnant women that any medication may adversely affect the baby
    • Weigh the actual benefits against the potential risks
    • Advise pregnant women that they should not take medications without checking with their health care provider first
Categories
Introduction to Nursing Pharmacology Nursing Pharmacology

Drugs and The Body

Drugs and the Body

Pharmacodynamics

  • Pharmacodynamics is the science of dealing with interactions between living organisms and foreign chemicals
  • Chemical reactions occur continuously in the body of each living system
  • When other chemicals (drugs) are added to the body, additional effects occur

Drug Actions

  • To replace or act as substitutes for missing chemicals
  • To increase or stimulate certain cellular activities
  • To depress or slow certain cellular activities
  • To interfere with the functioning of foreign cells

Receptor Cells

  • Receptor site reacts to certain chemicals
  • The better the fit between receptor site and chemical, the more pronounced the reaction
  • Enzymes within the body are needed to break down the chemicals to open up the receptor site

Lock & Key

Drugs and The Body: Lock and Key
Drugs and The Body: Lock and Key

Enzymes

  • Drugs can interfere with the enzymes that may be catalysts for chemical reactions
  • Enzymes produce a cascade effect

Pharmacokinetics

  • Onset of drug action
  • Drug half-life
  • Timing of the peak effect
  • Duration of drug effects
  • Metabolism or biotransformation of the drug
  • Site of excretion

The Processes by Which Drugs Are Handled in the Body

The Processes by Which Drugs Are Handled in the Body
The Processes by Which Drugs Are Handled in the Body

Pharmacokinetics

  • Critical concentration
    • The amount of a drug that is needed to cause a therapeutic effect
  • Loading dose
    • A higher dose than that usually used for treatment
  • Dynamic equilibrium
    • The actual concentration that a drug reaches in the body

Dynamic Equilibrium

  • The actual amount of drug that reaches the body results in a dynamic equilibrium
  • Dynamic equilibrium is affected by:
    • Absorption
    • Distribution
    • Biotransformation
    • Excretion

Absorption

  • Administration
    • Affected by route of administration
    • Oral medications affected by presence of food in the stomach
  • First-pass effect
    • Medications are extensively metabolized by the liver

Factors Affecting Absorption

Factors That Affect Absorption of Drugs
Factors That Affect Absorption of Drugs

Distribution

  • Protein binding
  • Blood–brain barrier
  • Placenta/breast milk

Biotransformation

  • The liver is the single most important site for biotransformation (metabolism)
  • This process breaks down medications
  • It helps to prevent medications from causing adverse effects on the body

Excretion

  • Removal of drugs from the body
  • Kidneys play the most important role in the excretion of medication

Half-Life

  • Half-life is the time it takes for the amount of drug in the body to decrease to one-half the peak level
  • Half-life is affected by the absorption, distribution, metabolism, and excretion

Pharmacokinetics

Pharmacokinetics
Pharmacokinetics

Half-life

Half-Life
Half-Life

Calculating Half-Life

Focus on Calculations
Focus on Calculations

Factors Influencing Drug Effects

  • Weight
  • Age
  • Gender
  • Physiologic factors
  • Pathologic factors
  • Genetic factors
  • Immunologic factors
  • Psychological factors
  • Environmental factors
  • Drug tolerance
  • Cumulative effect

Drug-to-Drug Interactions

  • Can occur any time two or more drugs are taken together
  • Can occur at:
    • Site of absorption
    • During distribution
    • During biotransformation
    • During excretion
    • At the site of action

Drug–Food Interaction

  • Certain foods interact with drugs
  • Drugs are best taken on an empty stomach

Drug–Laboratory Test Interaction

  • Drugs may alter the results of lab testing
  • Laboratory tests may be used to monitor the effects of other medications
Categories
Introduction to Nursing Pharmacology Nursing Pharmacology

Introduction to Drugs

Nurses’ Responsibility

  • Administering drug
  • Assessing for adverse drug effects
  • Intervening to make the drug regimen more tolerable
  • Providing patient teaching about drugs and the drug regimen
  • Monitoring and prevention of medication errors

Pharmacology

  • Pharmacology is the study of the biological effects of chemicals
  • Health care providers focus on how chemicals act on living organisms

Pharmacotherapeutics

  • A branch of pharmacology that uses drugs to treat, prevent, and diagnose disease
  • Pharmacotherapeutics focuses on:
    • The drug’s effect on the body
    • The body’s response to the drugs
  • Drug effects
    • Therapeutic
    • Adverse

Sources of Drugs

  • Plants
  • Animal products
  • Inorganic compounds
  • Synthetic sources

Plants

Focus on Drugs Derived From Plants
Focus on Drugs Derived From Plants

Animal Products

  • Animal products are used to replace human chemicals
  • Used less frequently due to genetic engineering
  • Synthetic preparations are considered safer

Inorganic Compounds

Focus on Elements Used for Their Therapeutic Effects
Focus on Elements Used for Their Therapeutic Effects

Synthetic Sources

  • Genetic engineering is used to alter bacteria to produce chemicals that are therapeutic and effective
  • Changes in chemical structure can make drugs more potent, more stable, and less toxic

Drug Evaluation

  • Preclinical trials
    • Chemicals tested on laboratory animals
  • Phase I studies
    • Chemicals tested on human volunteers
  • Phase II studies
    • Drug tried on informed patients
  • Phase III studies
    • Drug used in vast clinical market
  • Phase IV studies
    • Continual evaluation of the drug

Legislation

Focus on Federal Legislation Affecting the Clinical Use of Drugs
Focus on Federal Legislation Affecting the Clinical Use of Drugs

Pregnancy Category

FDA Pregnancy Categories
FDA Pregnancy Categories

Controlled Substances

DEA Schedules of Controlled Substances
DEA Schedules of Controlled Substances

Drug Names

  • Chemical name
  • Generic name
  • Trade name

Drug Name

  • Chemical name
    • (+/-)-2-(p-isobutylphenyl) propionic acid
  • Generic name
    • Ibuprofen
  • Trade name
    • Motrin®, Advil®
Mosby Items and Derived Items
Mosby Items and Derived Items

Types of Drugs

  • Over-the-counter drugs
  • Prescription drugs

Over-the-Counter Drugs

  • Drugs considered very safe and useful to patients without a prescription
  • Drugs may previously have been prescription medications (eg, loratadine)

Concerns With OTC Medications

  • OTC drugs can mask the signs and symptoms of underlying disease
  • Taking OTC drugs with prescription medications can result in drug interaction
  • Taking prescription medication incorrectly with OTC drugs could result in serious overdose

Sources of Drug Information

  • Reference books
  • Journals
  • Internet

Chapter 1
Introduction to Drugs
Nurses’ Responsibility
Administering drug
Assessing for adverse drug effects
Intervening to make the drug regimen more tolerable
Providing patient teaching about drugs and the drug regimen
Monitoring and prevention of medication errors
Pharmacology
Pharmacology is the study of the biological effects of chemicals
Health care providers focus on how chemicals act on living organisms
Pharmacotherapeutics
A branch of pharmacology that uses drugs to treat, prevent, and diagnose disease
Pharmacotherapeutics focuses on:
The drug’s effect on the body
The body’s response to the drugs
Drug effects
Therapeutic
Adverse
Sources of Drugs
Plants
Animal products
Inorganic compounds
Synthetic sources
Plants
Animal Products
Animal products are used to replace human chemicals
Used less frequently due to genetic engineering
Synthetic preparations are considered safer
Inorganic Compounds
Synthetic Sources
Genetic engineering is used to alter bacteria to produce chemicals that are therapeutic and effective
Changes in chemical structure can make drugs more potent, more stable, and less toxic
Drug Evaluation
Preclinical trials
Chemicals tested on laboratory animals
Phase I studies
Chemicals tested on human volunteers
Phase II studies
Drug tried on informed patients
Phase III studies
Drug used in vast clinical market
Phase IV studies
Continual evaluation of the drug
Legislation
Pregnancy Categories
Controlled Substances
Drug Names
Chemical name
Generic name
Trade name
Drug Name
Chemical name
(+/-)-2-(p-isobutylphenyl) propionic acid
Generic name
Ibuprofen
Trade name
Motrin®, Advil®
Types of Drugs
Over-the-counter drugs
Prescription drugs
Over-the-Counter Drugs
Drugs considered very safe and useful to patients without a prescription
Drugs may previously have been prescription medications (eg, loratadine)
Concerns With OTC Medications
OTC drugs can mask the signs and symptoms of underlying disease
Taking OTC drugs with prescription medications can result in drug interaction
Taking prescription medication incorrectly with OTC drugs could result in serious overdose
Sources of Drug Information
Package insert
Reference books
Journals
Internet