Download Medication Interactions

Geropharmacology
CHAPTER 9
Copyright © 2016 by Elsevier, Inc. All rights reserved.
Pharmacokinetics
 Study of the movement and actions of a
drug in the body
 Absorption
 Distribution
 Metabolism
 Excretion
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Pharmacokinetics (Cont.)
Absorption
 Route of administration
 Bioavailability
 Amount of drug that passes through
absorbing surfaces in body
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Pharmacokinetics (Cont.)
 Distribution
 Once absorbed, systemic circulation
transports drug to receptor site on target organ
 Distribution to organs with lower blood flow
occurs more slowly and results in lower
concentrations
 Depends on the availability of plasma protein
in the form of lipoprotein, globulins, and
especially albumin
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Pharmacokinetics (Cont.)
 Excretion
 Drugs and their metabolites are excreted in
sweat, saliva, and other secretions but
primarily through kidneys
 Renal drug excretion occurs when drug is
passed through kidney and involves
glomerular filtration, active tubular secretion,
and passive tubular reabsorption
 Assessment of creatinine clearance rates an
important consideration in older adults to
prevent drug toxicity
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Pharmacodynamics
 Physiological interaction between
medication and the body
 The older a person gets, the more likely
he or she will have altered unreliable
pharmacodynamics
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Issues in Medication Use
 Polypharmacy
 Taking multiple medications at same time,
approximately five or more
 Above five medications increase risk for
frailty, disability, death, and falls
 Increased risk for medication interactions
 Increased risk for adverse events
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Issues in Medication Use (Cont.)
 Medication Interactions
 The more prescribed medications or other
substances, the greater the possibility of
interactions
 When given at the same time may potentiate
each other
 Types of interactions to consider:
 Medication-herb/supplement interactions (Table
9-1)
 Medication-food interactions (Table 9-2)
 Medication-medication interactions
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Safe Administration of Medications
via Enteral Feeding Tubes
 High risk for medication errors
 Possible outcomes:
 Occluded tube
 Reduced drug effect
 Drug toxicity
 Patient harm
 Patient death
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Safe Administration of Medications
via Enteral Feeding Tubes (Cont.)
 The three most common errors
 Incompatible route
 Improper preparation
 Improper administration
 Can lead to altered absorption,
distribution, excretion, or contribute to
alterations in pharmacodynamics
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Issues in Medication Use
 Adverse Drug Reactions (ADR) or Events
 Occurs when there is a noxious response to a
medication
 Corticosteroids, anticoagulants, sedative
hypnotics, immunosuppressants, and
chemotherapeutic agents are of concern
 Allergic reactions are more common in the older
adult as the immune system decreases in
function
 To minimize the likelihood of ADRs: “start low, go
slow, but go”
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Issues in Medication Use (Cont.)
 “Beer’s Criteria”
 Potentially inappropriate medication
 Drugs identified to have a higher than
usual risk when used in older adults (Box
9-7)
 Overwhelming benefit versus risk
documentation when prescribing these
drugs considered a standard of practice
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Issues in Medication Use (Cont.)
 Psychoactive Medications
 Affect mental function, which in turn can affect
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behavior
Medications with psychoactive properties have
a higher risk for adverse events
Never be used as a “quick fix”
Requires a thorough assessment
Antipsychotics, when used appropriately and
cautiously, can provide relief from frightening
and distressing symptoms
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Issues in Medication Use (Cont.)
 Issues Associated with Psychoactive
Medications
 Malignant syndrome
 Movement disorders
 Acute dystonia
 Akathisia
 Parkinsonian symptoms
 Tardive dyskinesia
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Promoting Healthy Aging: Implications
for Gerontological Practice
 Ensure medication is used appropriately, effectively, and
safely
 Monitor for signs and symptoms of ADRs
 Prompt recognition of changes in patient status that can
affect drug regimen
 Patient and family education on purpose and side
effects of all medications to enhance safe compliance
with drug therapy
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Promoting Healthy Aging: Implications
for Gerontological Practice (Cont.)
 Assessment
 The “brown bag approach” asks the person to
bring in all medications being taken, including
over the counters, herbals, and neutraceuticals
or dietary supplements
 Ask person how he or she actually takes
medicine rather than depending on label
 Analysis assessment findings related to
medications (Box 9-8)
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Promoting Healthy Aging:
Implications for Gerontological
Practice (Cont.)
 Education
 Most common intervention to promote medication adherence
 Promotion of healthy aging related to medication use
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Key persons
Environment
Timing
Communication
Reinforce teaching
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Promoting Healthy Aging with
Safe Medication Use
 Education
 Assessment of patient’s readiness to
learn, ability to comprehend, and
functional capacity to incorporate lifestyle
adaptations for medication management
• Pamphlets and booklets written in lay terms
and in appropriate language and reading level
should be available
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Promoting Healthy Aging with
Safe Medication Use (Cont.)
Reducing Adverse Medication Events
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Question 1
Drugs and their metabolites are excreted
primarily through:
a. sweat.
b. saliva.
c. liver.
d. kidneys.
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Question 2
Which of the following is most likely to mimic
symptoms of Parkinson’s disease?
a. Antidepressants
b. Antipsychotics
c. Antianxiety agents
d. Mood stabilizers
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