Transcript Pharmacology and the Nursing Process, 4th ed. Lilley/Harrington

Chapter 2
PHARMACOLOGIC PRINCIPLES
DSN
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KEVIN DOBI, MS, APRN
Pharmacologic Principles
2
 Drug
 Any chemical that affects the physiologic processes
of a living organism
 Pharmacology
 Study or science of drugs
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Drug Names
Chemical name
3
 Describes the drug’s chemical composition and
molecular structure
Generic name (nonproprietary name)
 Name given by the United States Adopted Names
Council
Trade name (proprietary name)
 The drug has a registered trademark; use
of the name is restricted by the drug’s patent owner
(usually the manufacturer)
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Chemical, Generic, and Trade names and
Chemical Structure of Ibuprofen
4
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Pharmacologic Principles
5
 Pharmaceutics
 Pharmacokinetics
 Pharmacodynamics
 Pharmacotherapeutics
 Pharmacognosy
 Pharmacoeconomics
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Pharmaceutics
6
 The study of how various drug forms
influence the way in which the drug affects
the body
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Inc.
Pharmacokinetics
7
 The study of what the body does to the drug
 Absorption
 Distribution
 Metabolism
 Excretion
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Classroom Response Question
8
The nurse is giving a medication that has a high first-pass
effect. The health care provider has changed the route from
IV to PO. The nurse expects the oral dose to be
A. higher because of the first-pass effect.
B. lower because of the first-pass effect.
C. the same as the IV dose.
D. unchanged.
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Pharmacodynamics
9
 The study of what the drug does to the body
 The mechanism of drug actions in living tissues
 Drug-receptor relationships
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Phases of Drug Activity
10
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Classroom Response Question
11
A patient is complaining of severe pain and has orders for
morphine sulfate. The nurse knows that the route that would
give the slowest pain relief would be which route?
A.
B.
C.
D.
IV
IM
Subcut
PO
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Pharmacotherapeutics
12
 The clinical use of drugs to prevent and treat
diseases
 Defines principles of drug actions—the
cellular processes that change in response to
the presence of drug molecules
 Drugs are organized into pharmacologic
classes
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Pharmacognosy
13
 The study of natural (versus synthetic) drug
sources (i.e., plant, animals, minerals)
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Pharmaceutics
14
 Different drug dosage forms have different
pharmaceutical properties.
 Dosage form determines the rate of drug
dissolution (dissolving of solid dosage forms
and their absorption from the GI tract).


Enteric-coated tablets
Extended-release forms
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Classroom Response Question
15
A patient is prescribed ibuprofen 200 mg PO every 4 hours
as needed for pain. The pharmacy sends up enteric-coated
tablets, but the patient refuses the tablets, stating that she
cannot swallow pills. What will the nurse do?
A. Crush the tablets and mix them with applesauce or
pudding.
B. Call the pharmacy and ask for the liquid form of the
medication.
C. Call the pharmacy and ask for the IV form of the
medication.
D. Encourage the patient to try to swallow the tablets.
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16
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Pharmacokinetics
17
 A drug’s time to onset of action, time to peak
effect, and duration of action
 Study of what happens to a drug from the
time it is put into the body until the parent
drug and all metabolites have left the body
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Pharmacokinetics: Absorption
18
 Movement of a drug from its site of
administration into the bloodstream for
distribution to the tissues
Bioavailability
 First-pass effect

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Routes
19
 A drug’s route of administration affects the
rate and extent of absorption of that drug
Enteral (GI tract)
 Parenteral
 Topical

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Enteral Route
20
 The drug is absorbed into the systemic
circulation through the oral or gastric mucosa
or the small intestine
Oral
 Sublingual
 Buccal
 Rectal (can also be topical)

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Parenteral Route
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 Intravenous (fastest delivery into the blood
circulation)
 Intramuscular
 Subcutaneous
 Intradermal
 Intraarterial
 Intrathecal
 Intraarticular
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Topical Route
22
 Skin (including transdermal patches)
 Eyes
 Ears
 Nose
 Lungs (inhalation)
 Rectum
 Vagina
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Classroom Response Question
23
The nurse is preparing to administer a transdermal patch to
a patient and finds that the patient already has a
medication patch on his right upper chest. What will the
nurse do?
A. Remove the old medication patch and notify the health
care provider
B. Apply the new patch without removing the old one
C. Remove the old patch and apply the new patch in the
same spot
D. Remove the old patch and apply the new patch to a
different, clean area
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Distribution
24
The transport of a drug by the bloodstream to its
site of action
 Protein-binding
 Water-soluble vs. fat-soluble
 Blood-brain barrier
 Areas of rapid distribution: heart, liver,
kidneys, brain
 Areas of slow distribution: muscle, skin, fat
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Protein Binding of Drugs
25
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Metabolism/Biotransformation
26
The biochemical alteration of a drug into an
inactive metabolite, a more soluble compound,
a more potent active metabolite, or a less active
metabolite
 Liver (main organ)
 Skeletal muscle
 Kidneys
 Lungs
 Plasma
 Intestinal mucosa
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Drug Transport in the Body
27
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Metabolism/Biotransformation
(cont’d.)
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Factors that decrease metabolism
 Cardiovascular dysfunction
 Renal insufficiency
 Starvation
 Obstructive jaundice
 Slow acetylator
 Ketoconazole therapy
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Metabolism/Biotransformation (cont’d)
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Factors that increase metabolism
 Fast acetylator
 Barbiturate therapy
 Rifampin therapy
 Phenytoin therapy
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Excretion
30
The elimination of drugs from the body
 Kidneys (main organ)
 Liver
 Bowel
Biliary excretion
 Enterohepatic recirculation

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Renal Drug Excretion
31
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Half-life
32
 The time it takes for one half of the original
amount of a drug to be removed from the body
 A measure of the rate at which a drug is
removed from the body
 Most drugs considered to be effectively
removed after about five half-lives
 Steady state
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The Movement of Drugs
Through the Body
33
Drug actions
 The cellular processes involved in the drug and cell
interaction
Drug effect
 The physiologic reaction of the body to the drug
 Includes onset, peak, and duration of action
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Onset, Peak, and Duration
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Onset
 The time it takes for the drug to elicit a
therapeutic response
Peak
 The time it takes for a drug to reach its maximum
therapeutic response
Duration
 The time a drug concentration is sufficient to elicit a
therapeutic response
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35
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Therapeutic Drug Monitoring
36
Peak level
 Highest blood level
Trough level
 Lowest blood level
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Pharmacodynamics:
Mechanisms of Action
37
 Receptor interactions
 Enzyme interactions
 Nonselective interactions
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38
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39
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Pharmacotherapeutics:
Types of Therapies
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 Acute therapy
 Maintenance therapy
 Supplemental/replacement therapy
 Palliative therapy
 Supportive therapy
 Prophylactic therapy
 Empiric therapy
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Contraindications
41
 Any characteristic of the patient, especially a
disease state, that makes the use of a given
medication dangerous for the patient
 It is important to assess for contraindications!
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Monitoring
42
 Evaluating the clinical response of the patient
to the treatment
 One must be familiar with the drug’s:
Intended therapeutic action (beneficial)
 Unintended but potential adverse effects
(predictable, adverse drug reactions)

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Monitoring (cont’d)
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 Therapeutic index
 Drug concentration
 Patient’s condition
 Tolerance and dependence
 Drug interactions (additive effect, synergistic
effect, antagonistic effect, incompatibility)
 Adverse drug events
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Monitoring (cont’d)
44
Adverse drug reactions




Pharmacologic reactions, including adverse effects
Hypersensitivity (allergic) reaction
Idiosyncratic reaction
Drug interaction
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Other Drug-Related Effects
45
 Teratogenic
 Mutagenic
 Carcinogenic
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Pharmacognosy
46
Four main sources for drugs
 Plants
 Animals
 Minerals
 Laboratory synthesis
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Toxicology
47
 The study of poisons and unwanted
responses to drugs and other chemicals
 Overlaps with pharmacotherapeutics
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The End
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