Chapter 1
Orientation to Pharmacology
Copyright © 2019 by Elsevier, Inc. All rights reserved.
Pharmacology
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A science that draws on information from
multiple disciplines, including:
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Anatomy
Physiology
Psychology
Chemistry
Microbiology
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2
Four Basic Terms
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Drug
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Any chemical that can affect living processes
Pharmacology

Study of drugs and their interactions with living
systems
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3
Four Basic Terms (Cont.)
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Clinical pharmacology
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Study of drugs in humans
Therapeutics
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Also known as pharmacotherapeutics
The use of drugs to diagnose, prevent, or treat
disease or to prevent pregnancy
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4
Orientation to Pharmacology
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Properties of an ideal drug
The therapeutic objective
Factors that determine the intensity of drug
responses
Therapeutics
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5
Three Most Important
Properties of an Ideal Drug
1.
2.
3.
Effectiveness: Most important property a drug
can have
Safety: Drug cannot produce harmful effects
Selectivity: Drug elicits only the response for
which it is given
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6
Examples of Adverse Effects
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Certain anticancer drugs can increase the risk
for infection (eg, cyclophosphamide,
methotrexate)
Opioid analgesics at high doses can cause
respiratory depression (eg, morphine,
meperidine)
Aspirin and other related drugs can cause
severe gastric ulceration, perforation, and
bleeding when they are taken for prolonged
periods of time
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Additional Properties
of an Ideal Drug
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Reversible action
Predictability
Ease of administration
Freedom from drug interactions
Low cost
Chemical stability
Simple generic name
However, no drug is ideal…
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8
Therapeutic Objective
of Drug Therapy

To provide maximum benefit with minimum harm
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9
Factors That Determine the
Intensity of Drug Responses
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Administration
Pharmacokinetics
Pharmacodynamics
Sources of individual variation
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10
Administration
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Important determinants of drug responses:
Dosage size, route, and timing
Medication errors
Patient adherence
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11
Pharmacokinetics
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Determining how much of the administered dose
gets to its sites of action
Impact of the body on drugs
Four major pharmacokinetic processes:
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Drug absorption
Drug distribution
Drug metabolism
Drug excretion
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12
Pharmacodynamics
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Impact of drugs on the body
Drug-receptor interaction
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Patient’s functional state
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Binding of the drug to its receptor
Influences pharmacodynamic processes
Placebo effects
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Also help to determine the responses a drug elicits
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13
Sources of Individual Variation
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Physiologic variables
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Pathologic variables
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Diminished function of kidneys and liver
Genetic variables
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Age, gender, and weight
Can alter the metabolism of drugs and predispose the
patient to unique interactions
Drug interactions
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14
Question 1
A nurse is caring for a patient who has an infection.
The healthcare provider has ordered an antimicrobial
drug for the patient. The nurse understands that which
of the following is the most important characteristic of
this drug?
A.
B.
C.
D.
That the drug will kill the microorganism
That the drug will be administered orally
That the drug does not have any harmful effects
That the drug does not interact with other drugs
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15
Question 2
A patient who was prescribed an oral medication to be taken 4 times
a day returns to the clinic for a follow-up visit. The patient tells the
nurse that he forgets to take two or three doses of the medication
each day. What is the most appropriate action that the nurse can
take?
A.
B.
C.
D.
Arranging for the patient to have a home healthcare nurse
Re-educating the patient about the medication and how it should
be taken
Determining whether the patient is experiencing any adverse
effects
Telling the patient to set an alarm as a reminder to take the drug
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