Transcript Chapter 2

Chapter 2
Principles of Drug Action
and Drug Interactions
Jeanelle F. Jimenez RN, BSN, CCRN
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Objectives
• Identify five basic principles of drug action.
• List three categories of drug administration
and state the routes of administration for
each category
• Describe nursing interventions that can
enhance drug absorption
• Differentiate between general and selective
types of drug distribution mechanisms
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Slide 2
Objectives (cont’d)
• Explain nursing assessments necessary to
evaluate potential problems associated with
the absorption of medications
• Name the process that inactivates drugs
• Identify the meaning and significance to the
nurse of the term half-life when used in
relation to drug therapy
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Slide 3
Objectives
• Compare and contrast the following terms
used in relationship to medications
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
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Desired action
Side effects
Adverse effects
Allergic reactions
Idiosyncratic reactions
• State the mechanisms whereby drug
interactions may occur
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Slide 4
Objectives (cont’d)
• Differentiate among the following terms used
in relationship to medications

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Additive effect
Synergistic effect
Antagonistic effect
Displacement
Interference
Incompatibility
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Slide 5
Principles of Drug Action
and Drug Interactions
• Basic principles
 An understanding of the human body’s
processes is important to grasp drug actions
and drug interactions in the body
A
B
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
C
D
Slide 6
5 Stages of Drug
Administration
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•
•
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Liberation
Absorption
Distribution
Metabolism
Excretion
Mosby items and derived items © 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Slide 7
Liberation
• The release of a drug from the dosage form
(liberation) and dissolved in body fluids
before it can be absorbed into body tissues
• Parenteral administration
• Percutaneous administration
Mosby items and derived items © 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Slide 8
Drug Stages After Administration
•
ADME
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Absorption – depends on route of
administration
Distribution – depends on circulation to be
transported throughout body
Metabolism – depends on enzyme systems
Excretion – depends on GI tract and kidneys
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Slide 9
Half-life of Drugs
• Factors modifying
the quantity of drug
reaching a site of
action after a single
oral dose
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Slide 10
Factors Affecting Drug
Response
•
Age
•
Body weight
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Metabolic rate
•
Illness
•
Psychological aspects
•
Tolerance of the medication
•
Dependence developed from the medication
•
Cumulative effect of the medication
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Slide 11
Responses to Drugs
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Desired effect
Side effects
Adverse effects
Idiosyncratic effects
Allergic reactions
Teratogen
Carcinogen
Mosby items and derived items © 2010, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc.
Slide 12