Alexander ch11 lecture

Copyright © 2017, 2012 Pearson Education, Inc. All Rights Reserved.
Advanced EMT
A Clinical-Reasoning Approach, 2nd Edition
Chapter 11
Principles of
Pharmacology

• The Advanced EMT applies fundamental
knowledge of medications in the Advanced EMT
scope of practice to patient assessment and
management.
Advanced EMT
Education Standard

1. Define key terms introduced in this chapter.
2. Give examples of each of the four sources of drugs.
3. Explain the role of the U.S. Food and Drug Administration
in the development and continued oversight of drugs.
4. Discuss relevant legislation regarding the administration
of prescription medications, including controlled
substances.
5. Identify the official, generic, and trade names of drugs in
the Advanced EMT scope of practice.
Objectives (1 of 3)

6. Describe the various forms in which drugs are supplied.
7. Describe the various types of medication packaging.
8. Explain each of the components of a drug profile.
9. Explain each of the following with respect to
pharmacology: drug absorption, drug distribution,
mechanism of action, and drug elimination.
10.Explain the roles of the kidneys and liver in drug
metabolism and excretion.
Objectives (2 of 3)

11.Explain factors that can affect the concentration of a drug
in a patient’s body.
12.Describe the concepts of drug receptor sites and protein
binding of medications.
13.Identify special populations in whom the administration of
drugs may need to be modified.
Objectives (3 of 3)

• AEMTs are responsible for administering
medications to ill and injured patients
• Some medications, administered incorrectly,
produce life-threatening consequences
• Must have understanding of pharmacology
• Pharmacology
– Study of origin, nature, properties, actions of drugs and
their effects on living organisms
Introduction

• What are some initial hypotheses about the cause
of the problem?
• What additional information would assist Mike and
Matt in determining the cause of the patient’s
condition?
• What initial steps in management should the crew
members take as they finish their assessment?
Think About It

• Four basic sources of medications
– Plant
– Animal
– Mineral
– Synthetic
Medication Sources

• Discovered in 1921, insulin has saved the lives of
15 million people with diabetes
• Insulin is mainly derived from the pancreas of pigs
and cows
Think About It

• Keep knowledge current by reviewing new
medication information
• Be familiar with reliable, up-to-date sources
– Physician’s Desk Reference (PDR)
– American Medical Association (AMA) drug evaluations
– Hospital Formulary
Medication Reference Material

• Consists of
– Medication name
– Classification
– Mechanism of action
– Indications
– Pharmacokinetics
– Side effects
– Routes of administration
– Contraindications
– Dose
– How the drug is supplied
– Special considerations
Medication Profile (1 of 5)

• Medication name
– Generic name
– Trade name
– Chemical name
• Classification
– Type of medication it is
– Different classification schemes used
– Mechanism of action
– Body system it works within

• Mechanism of action
– Way medication achieves its intended effects
• Indications
– Conditions that medication intended to treat
• Pharmacokinetics
– How the drug is absorbed, distributed to tissues,
eliminated from the body
• Side effects
– Unintended effects of medication

• Route of administration
– Way medication introduced into the body
• Contraindications
– Makes administration of drug harmful, even though
otherwise indicated for the medical problem
• Dose
– Amount and frequency of medication to be
administered

• How supplied
– Packaging and concentrations available
• Special considerations
– Special precautions to be observed when administering
drug to special patient populations

Medication Oversight and Regulation (1
of 6)
• Legislation
– Protect the public from unsafe and mislabeled
medications
• The Harrison Narcotic Act of 1914
– Regulations on importation, manufacture, sale, and use
of medications

of 6)
• The Food, Drug, and Cosmetic Act of 1938
– Provided additional protection to the public
– Revised in 1952 and 1962
– Provided for:
 Formation of FDA
 Mandated prescriptions required for addictive or harmful
medications
 Required labeling of medications that include addictive drugs
and potential side effects

of 6)
• Durham-Humphrey Amendments were added to
1938 Act
– Added in 1951
– Required pharmacists to dispense certain medication
only by prescription
– Defined OTC medications

of 6)
• The Comprehensive Drug Abuse Prevention and
Control Act of 1970
– Aka Controlled Substances Act
– Replaced the Harrison Narcotic Act of 1914
– Includes five schedules of controlled substances based
upon their potential for abuse
– Schedule I drugs have highest potential while Schedule
IV drugs have least potential

Table 11-1 (1 of 2)
Schedules of Controlled Substances
Schedule I
Schedule I medications have a high potential for abuse
and do not have any recognized medical use in the
United States.
Examples: heroin, LSD, mescaline, methaqualone
Schedule II
Schedule II medications have a high potential for abuse but
also have a recognized medical use in the United States.
These medications require a written prescription, are
restricted from phone renewals, and require oversight by a
physician.
Abuse may result in severe physical or psychological
dependence.
Examples: morphine, codeine, meperidine, hydrocodone,
and a host of very addictive stimulants and depressants
Schedule III
Schedule III medications have less abuse potential than
Schedule II medications and an accepted medical use.
Abuse can result in moderate to low physical or
psychological dependence.
Examples: anabolic steroids, nonprescription painkillers
combined with small amounts of Schedule II substances
such as acetaminophen with codeine or hydrocodone; also
medications that contain small amounts of opiates

Table 11-1 (2 of 2)
Schedules of Controlled Substances
SCHEDULE IV
Schedule IV medications have less abuse potential
than Schedule III medications and an accepted
medical use.
Abuse can result in less physical or psychological
dependence than drugs in Schedule III.
Examples: benzodiazepines, some barbiturates,
steroids, stimulants
SCHEDULE V
Schedule V medications have less abuse potential
than Schedule IV medications and an accepted
medical use.
Abuse can result in less physical or psychological
dependence than drugs in Schedule IV.
Examples: over-the-counter (OTC) medications for
cough or antidiarrheal medications that contain
small amounts of controlled substances
Source: U.S. Drug Enforcement Administration. n.d. “Drug Scheduling.” A Drug Info page on the DEA
website. http://www.dea/gov/druginfo/ds.shtml

• Medication safety and regulation
– The FDA is responsible for testing new medications;
food safety; testing of new medical devices; cosmetics
safety
– Testing phases
 Phase I
 Phase II
 Phase III
 Phase IV
of 6)

• Special considerations
– Pregnant patient
 Changes in anatomy and physiology
 Risk to the fetus
– Pediatric patients
 Physical differences between adult and child
 Differences on how medications affect children
 Pediatric drug dosing based on weight of patient
– Geriatric patients
 Differences in absorption, distribution, metabolism, and
elimination of medication
 Multiple medical conditions requiring medications
of 6)

Table 11-2
FDA Pregnancy Categories
Category Description
A Studies have not identified a risk to the fetus during pregnancy.
B Animal studies have not identified a risk to the fetus but there are no adequate
human studies.
OR
Adequate studies in humans have not demonstrated a risk to the fetus during
pregnancy but animal studies have produced adverse effects.
C Animal studies have demonstrated adverse effects but there are no adequate
studies in pregnant women; however, benefits may be acceptable despite the
potential risks.
OR
No adequate animal studies or adequate studies of pregnant women have been
performed.
D Studies have shown risk to the fetus. In some situations, benefits could outweigh
the risks.
X Studies have shown risk to the fetus. This risk outweighs any potential benefit to
the mother. Avoid using these medications in pregnant or potentially pregnant
patients.
Source: Gunatilake, R,, and A. S. Patel. n.d. “Drugs in Pregnancy.” A Gynecology and Obstretrics
page on the Merck Manual Professional Version website. Last updated January
2013. http://www.merckmanuals.com

Medication Names
• Trade name
– Proventil ®
• Chemical name
– α1 [(tert-butyl amino) methyl]-4-hydroxy-m-
xylene-α,α,́-diol sulfate (2:1) (salt)
• Generic name
– Albuterol sulfate
• Official name
– Albuterol sulfate USP

• Solid medications
– Tablet
– Capsule
– Powder
Medication Forms (1 of 3)

• Liquid medications
– Suspensions
– Tinctures
– Spirits
– Elixirs
– Syrups
– Emulsions

• Semisolid medications
– Lotions
– Creams
– Gels
– Ointments
– Medicated adhesive patches
• Gases
– Oxygen
– Nitrous oxide

Think About It
• Many drugs appropriate for topical administration
in adults are not appropriate for pediatric
administration

• Medications that affect the nervous system
– Sympathetic nervous system
 Sympathomimetics/adrenergic agonists
– Parasympathetic nervous system
 Parasympathomimetics/cholinergics
 Parasympathetic antagonists; aka parasympatholytics/
anticholinergics
Classifications of Medications (1 of 6)

Table 11-3
Adrenergic Receptors and Their Responses to Stimulation
Alpha1 Peripheral vasoconstriction
Alpha2 Peripheral vasodilation
Little or no bronchoconstriction
Beta1 Increased heart rate
Increased automaticity
Increased myocardial contractility
Increased conductivity
Beta2 Bronchodilation
Vasodilation

• Analgesics
– Medications that reduce pain
– Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Anti-anxiety and sedative-hypnotic
– Designed to reduce anxiety
– Barbiturates, benzodiazepines, nonbarbiturate
hypnotics

• Stimulants
– Central nervous system excitation
– Caffeine, cocaine, amphetamine
• Depressants
– Slow CNS activity
– Treat anxiety, muscle tension, stress, pain, insomnia

• Anticonvulsants
– Antiseizure/antiepileptic; treat seizures
• Psychotherapeutic
– Treat mental illness, anxiety disorders, psychotic
disorders
• Respiratory
– OTC medications
– Beta2-agonists
– Corticosteroids

• Cardiovascular
– Antidysrhythmic medications treat abnormal heart
rhythms.
– Antihypertensive medications keeps blood pressure
under control.
– Antiplatelet and anticoagulant agents reduce potential
for blood clots in coronary arteries.
– Fibrinolytic agents breakdown fibrin network of existing
blood clots.

• Diabetic
– Medications to control blood sugar
• Immunosuppressants
– Inhibit actions of immune system
– Decrease body’s attack on its own tissues in
autoimmune disease
– Reduce the likelihood that the body will reject
a transplanted organ

Medication Packaging
• Packaged to accommodate intended use.
• Protects medication during storage.
• Packaged as
– Prefilled syringes
– Vials
– Nonconstituted medications
– Ampules
– Nebules

Figure 11-1
Example of a prefilled syringe.

Figure 11-2
Examples of medication vials.

Figure 11-3
Examples of nonconstituted medication vials.

Figure 11-4
Examples of ampules.

Think About It
• Since medications can be administered by
different routes, they are packaged to
accommodate their intended use
• For example, since epinephrine is administered
by injection, it is commonly supplied in a
prefilled syringe

Pharmacokinetics (1 of 7)
• Branch of pharmacology concerned with way
drugs are absorbed, distributed, metabolized, and
eliminated from body.
• Absorption
– Medication introduced to body must first enter into
body’s circulatory system.

• Distribution
– After medication enters the circulation, it must be
distributed to target tissues on which it is intended
to act.
• Biotransformation
– Chemically changing medication through metabolism
• Primary organ for metabolizing and
biotransforming medications is the liver
• Bioavailability is the amount of drug that is still
active when it reaches target tissues

• Elimination
– Medications are broken down into metabolites
– Excreted from body via
 Urine
 Respiration
 Feces
 Perspiration
 Mammary glands during lactation

• Pharmacodynamics (mechanism of action)
– Way specific medications achieve desired effect(s)
– Effects are the result of medication binding with cellular
receptors
• Receptor sites
– Specific receptor sites on cells activated by substances
that have affinity for particular type of receptor; inhibit
or enhance functions of the cell

Figure 11-5
Receptor site binding.

Figure 11-6
Receptor site blocked by medication with greater affinity to site.

• Types of mechanisms of action
– Binding with a receptor site
– Changing the cell
– Combining with another chemical substance
– Changing metabolic pathways

• Dose–response relationship
– Therapeutic threshold
 Loading dose is administered to raise level of medication in
circulation to point where desired effect occurs
– Requires administration of additional doses

Figure 11-7
Minimum and maximum dose for a medication over time.

• Dose–response relationship (continued)
– Half-life
 Time between each dose determined by how long it takes for
body to metabolize 50% of peak concentration
– Therapeutic index
 Ratio of dose of medication lethal in 50% of population (LD50);
dose effective in 50% of population (ED50)

Table 10-4 (1 of 2)
Factors That Influence Medication Effects
Factor Description of Altered Response
Age Patients at the extremes of age have different responses to medications than might
be expected. Infants do not have mature organ systems, and their liver is often not mature
enough to process and metabolize drugs efficiently. Their kidney function may not remove
the medication from the body as quickly. Elderly patients often have other multiple medical
conditions, such as liver and kidney dysfunction, that result in the same effect. They may be
unable to metabolize drugs efficiently due to liver damage, and they cannot filter and
eliminate medications as rapidly because the kidneys no longer function at peak efficiency.
Gender and body mass Larger patients require more of a given medication to achieve the therapeutic dose. You will
determine the amount of medication to be administered to the patient based on body weight.
Because men tend to have a greater weight and muscle mass, they tend to require a higher
dose than women. If the weights are equal, you still may need to make a specified change in
the dose due to the different fat-to-muscle ratio for women.
Pathologic state Patients with significant liver disease or kidney failure will not experience the same drug
response as an otherwise healthy individual. You may need to make adjustments when the
patient has any significant renal or hepatic disease because he will not be able to metabolize
or eliminate the drug efficiently.
Genetic factors Patients who have a genetic disorder that affects either thyroid hormone function or growth
hormone secretion may require a dose adjustment. Any disease that affects metabolic rate
significantly alters the expected response to the medication. Idiosyncratic reactions are
thought to be because of genetic variations in the way patients respond to drugs or their
metabolites.

Table 10-4 (2 of 2)
Factors That Influence Medication Effects
Factor Description of Altered Response
Time of administration This is primarily of concern when the medication is administered orally. The presence
or lack of food in the digestive tract has a dramatic impact on the rate of absorption.
Medications are absorbed more rapidly on an empty stomach and more slowly when food
is present in the stomach.
Psychological effects Psychological stress may alter the rate at which the body is able to metabolize a medication.
It has been known for a long time that patients get a greater effect if they believe that the
medication will help them. Imagine the difference between telling them, “This is not very
strong, but it is all I can give you for pain” and telling them, “I am going to give you a
medication to reduce your pain. It works very quickly so I need you to tell me as soon as it
starts to work so I can monitor the effect and not give you too much.” One statement
enhances the patient’s expectation of how well the drug will work and the other diminishes it
significantly.

• Idiosyncratic reactions
– Unusual reactions
• Iatrogenic effect
– Adverse effects caused by treatment provided
• Tolerance
– Medication produces less of an effect over time
• Cross-tolerance
– Tolerance to medications of same classification
Factors Influencing Medication Effects (1
of 2)

• Habituation
– An increase in tolerance following repeated doses
• Potentiation
– Enhancement of one medication when combined with
another
• Synergism
– The enhancement of multiple medications when
combined with one another
Factors Influencing Medication Effects (2
of 2)

• Controlled substances tracked closely and
accounted for following strict DEA guidelines.
• Medications stored at controlled temperature and
protected from light, exposure to air, and moisture.
Medication Storage

Chapter Summary
• The ability to identify medications by name and
classification is important and useful
• It is vital to understand how different medications
work and what effects they will have on your
patient
• You must be familiar with the various forms of
medications and how they are packaged
• Stay current with medications your patients may
be taking

Alexander ch11 lecture

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Alexander ch11 lecture