Download 5. Pain Management

Physiology, Assessment and
Pharmacology
of Pain
1
Reasons That There is A Lot of
Pain in the United States
2
Reasons That There is A Lot of Pain in
the United States
• Some people feel like you have to suffer with a
certain amount of pain, such as in order to go
to heaven
• Lack of preventative care
• Our country does not do a great job dealing
with pain because health care practitioners
are wary of creating dependence
• Health care practitioners do not believe
patients’ reports of pain
3
Goal Setting with Pain
4
Goal Setting with Pain
• Pain level
– Ex. a 3 with rest and a 5 with movement
• Functional roles
– Ex. be able to walk up stairs, be able to play on the
floor with children
5
Pain
The Fifth Vital Sign
6
Pain
The Fifth Vital Sign
•The patient is the expert
•The nurse is not a mind-reader
•Nursing Implications
•Support the patient
•Be the squeaky wheel for the patient
•Be a patient advocate
7
Pain Facts
8
Pain Facts
• Patient is the expert about his/her pain.
• All pain is "real" -- even if we do not know the cause.
– Cannot correlate imaging with the pain complaint
• Pain is NOT a natural outcome of growing old.
– Reporting of pain by the elderly may be atypical.
• Elderly and children can safely receive opioid analgesics.
– High sugar concentration up to two months old serves as an
analgesic
9
Scary Facts about Pain
10
Scary Facts about Pain
• 89% Americans > 18 suffer from pain
each month.
• 43% adults (83 million!) report pain frequently affects
participation in some activities.
• >116 million live with chronic pain and >25 million suffer acute
pain resulting from injury or surgery.
– This is a conservative estimate
• 80% postoperative patients report moderate to severe pain.
• 80% of patients believe they must live with their pain.
– Many older people think that it is a normal part of aging
• 68% of pain sufferers feel anxious, irritable &/or depressed
– This may impact their ability to sleep
• Sleep may be disrupted because of pain, but the treatment should focus on pain,
not on sleep
• 12% state their MD never asks them about their pain.
11
Appalling Facts about Pain
12
Appalling Facts about Pain
 Despite increased knowledge and new
technologies that can greatly relieve many
pain types, most pain still goes untreated,
undertreated or improperly treated.
 90% of pain can be treated with very simple tools
 After more than 20 years research showing
ineffective pain management.
• MD’s still prescribed 75% of the appropriate opioid
analgesic dose.
• The prescriber needs to avoid dose ranges because it
leaves the nurse to choose the dose
• Nurses still administered 66% of the prescribed
dose.
13
Barriers to Effective Pain
Management
14
Barriers to Effective Pain Management
•Lack of understanding of pharmacologics
•Inadequate assessment
•Inadequate communication
•Underutilization of nonpharmacologics
•Inadequate use of age-specific data
•People respond to different types of medication at different ages
•Ex. a nonsteroidal is more dangerous for elderly people than an opioid
15
Pain Etiology
16
Pain Etiology
• Disease Related
– Chronic pain
• Fibromyalgia
• Osteoarthritis
• Cancer pain
• Trauma Related
• Treatment Related
– Surgery
– Chemotherapy and radiation
17
Health Consequences to Not
Treating Pain Adequately
Things that Increase
18
Health Consequences to Not Treating Pain
Adequately
Things that Increase
 Stress
 Metabolic Rate
 Blood Clotting
 Water Retention
 Hormone Imbalance
19
Health Consequences to Not
Treating Pain Adequately
Things that Decrease
20
Health Consequences to Not Treating Pain
Adequately
Things that Decrease
 Immune System
 Healing
 GI Function
 Mobility
 Appetite
 Sleep
21
Pain And Clinical Sequelae
Ventilation
22
Pain And Clinical Sequelae
Ventilation
Splinting and Guarding
Altered Respiratory Pattern & Effort
Decreased lung capacity
V/Q Abnormalities
Ineffective Airway
Clearance (cough)
Shunt
V/Q Mismatch
Diffusion Defect
Retention of
Secretions
Pneumonia
Atelectasis
PaO2
Puntillo, 1991
23
Correlation Between Pain and
Respiratory Depression
24
Correlation Between Pain and
Respiratory Depression
• Pulmonary function improves when pain is adequately controlled.
• In patients with upper abdominal surgery, vital capacity is increased
when pain is relieved.
• High pain scores are positively correlated with post-op pulmonary
complications.
• If respirations decrease to 8-10 respirations per minute, there is a risk
of respiratory depression
• Pain relief occurs before respiratory depression.
– Patients have pain relief and sleepiness before having respiratory depression
• Patients develop tolerance to the respiratory depressant effects of
narcotics.
– Usually develops after about one week
25
Pain And Clinical Sequelae
Systemic Perfusion
26
Pain And Clinical Sequelae
Systemic Perfusion
Pain
Vasopressin,
Aldosterone,
Renin,
Angiotensin
Fluid Retention by the kidneys
Preload
Tachycardia
27
Pain And Clinical Sequelae
Cardiac Perfusion
28
Pain And Clinical Sequelae
Cardiac Perfusion
Pain
Sympathetic Nervous System Activation
Afterload
Tachycardia
Myocardial Blood flow
Myocardial O2 Consumption
Myocardial Ischemia
Myocardial Infarction
29
Pain and Clinical Sequelae
Peripheral Perfusion One
30
Pain and Clinical Sequelae
Peripheral Perfusion One
Pain
Sympathetic Nervous System Activation
Vasoconstriction
Regional Blood Flow
Wound Healing
31
Pain and Clinical Sequelae
Peripheral Perfusion One
32
Pain and Clinical Sequelae
Peripheral Perfusion One
Pain
DVT
DVT
DVT
Immobility
Venous Stasis
Risk of DVT
(Deep Venous Thrombosis)
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33
A Call to Action!!!
34
A Call to Action !!!
- Inadequate pain assessment is the greatest barrier to effective pain management
1.
Treat pain as the fifth vital sign.
2.
Believe the patient’s self-report of pain.
-
Listen to what the patient says
-
Look at the patient as the whole
3.
Employ a team approach to pain assessment.
-
4.
Others who can help the patient
-
Family can state what is normal for the pain, what the patient can or cannot do
-
Pharmacists
-
Physical therapist can talk about progress, baselines, changes in pain with therapy, is the medication
appropriate for the therapy
-
Clinical nurse assistant helps keep the patient clean, assesses pain
Conduct ongoing assessments of pain.
-
Aim to achieve optimum effectiveness of a pain management plan through a concerted effort by
patients, their families and caregivers, and healthcare professionals
-
Must identify new pain and changes in pain
35
Definition of Pain
36
Definition Of Pain
• Pain - An unpleasant sensory and emotional experience
associated with actual or potential tissue damage.
– Sensory component – physical aspect of pain, what it
keeps the patient from doing
– Emotional component – tolerance for pain, affects daily
life, depression, anxiety, decision about whether or not
to tell the health care professional
• International Association for the Study of Pain
37
Alternative Definition of Pain
38
Alternative Definition Of Pain
Pain is what the patient says it is,
when the patient says it is
occurring.
»Margo McCaffrey, 1989
39
Categories of Pain
40
Categories of Pain
• Temporal aspects of pain
– Acute pain
– Chronic pain
– Cancer pain
• Physiology of pain
– Somatic pain
• Cutaneous pain
• Deep pain
– Visceral pain
– Neuropathic pain
41
Pain Descriptions and Consequences
Temporal Aspect of Pain
42
Pain Descriptions and Consequences
Temporal Aspect of Pain
Type
Description
Consequences
Acute
Pain
 Biologically necessary physiologic
response that provokes escape/protection
reaction (John C. Rawlingson, 1994).
• Immediate Onset
• Warning: Tissue Injury
• Usually Temporary
•Escape from Source of
Injury
•Protection of Injured Site
Chronic
Pain
 No useful biological purpose
• Less physiologic correlation
• The original tissue injury may resolve but
the pain lingers so the cause may not be
clear
• Pain takes on a disease status of its own,
requiring its own form of treatment.
• Lasts longer than 6 months
•The pain lasts longer than expected or
warranted for the injury
•Mostly due to poorly managed acute pain
• Decreased quality of life
• Decreased relationships
•Decreased mood, leading
to increased risk of suicide
 Can be acute, chronic (persistent –
12/24 hours per day), or a combination of
the two
•Decreased quality of life
•Decreased relationships
•Decreased mood, leading
43
to increased risk of suicide
Cancer
Pain
Types of Pain
Physiology of Pain
44
Types of Pain
Physiology of Pain
Type
Somatic
• Cutaneous
• Deep
Visceral
Neuropathic
Source
Characteristics
 Structural tissues:
• Bone
• Skin
• Soft tissue
• Joint
•Ex. breaking a bone, contusion, arthritis, sprain
or strain, pressure ulcer
Well-localized
• Intermittent or constant
• Aching, gnawing, sharp, throbbing , or cramping
•Ask about pain, discomfort, soreness, pressure,
etc.
 Deep tissues or organs and surrounding
structural tissues
 Results from stretching, distention or
ischemia of tissues
Ex. menstrual cramps, liver cancer leads to
stretching of the liver capsule (which has nerve
endings, even though the liver does not have
nerve endings)
Deep, boring, diffuse, poorly defined, frequently
with referred component
 Affects the peripheral receptors, afferent
fibers, CNS
Shooting, burning, stabbing, lancinating (cutting);
radicular (nerve root) or radiating pattern
 Pain from touch (allodynia)
- touch ends up in the layer of the spinal cord
where pain is perceived
Drugs such as non-steroidals and non-opiods will
not work
45
Referred Pain
46
Referred Pain
 Originates at a visceral site but
perceived as originating in part
of body wall that is innervated
by neurons entering the same
segment of the nervous system
47
Pain Threshold and Pain
Tolerance
48
Pain Threshold and Tolerance
 Pain Threshold
• The point at which a stimulus is perceived as painful.
 Pain Tolerance
• The maximum intensity or duration of pain that a
person is willing to endure before the person wants
something done about the pain.
• This varies according to the person, culture, etc.
49
What is an Important Difference
between Acute and Chronic Pain?
50
What is an Important Difference between
Acute and Chronic Pain?
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2.
Pain pathways are not
involved in chronic pain
Chronic pain serves no
biological purpose
Acute pain is more easily
borne by the patient
Chronic pain is not as
intense as acute pain
P
1.
Pain Pathways
52
Pain Pathways
• First-order neurons
• Second-order neurons
• Third-order neurons
53
Pain Pathways
First-Order Neurons
54
Pain Pathways
First-Order Neurons
• Nociceptors sense substances that indicate tissue
damage.
• Nociceptor sensitivity may be increased by
inflammatory mediators – notably prostaglandins,
bradykinin, histamine.
– Sensitizes the tissue in the area
– Sodium rushes in and potassium rushes out, leading to an
action potential
• Go into the CNS into the dorsal horn
55
Pain Pathways
Second-Order Neurons
56
Pain Pathways
Second-Order Neurons
• Process nociceptive information.
• Communicate with various reflex networks
and sensory pathways in the spinal cord and
travel directly to the thalamus.
– Only when the information arrives in the
thalamus, does it recognize the information as
pain and that it should send it to the cortex
57
Pain Pathways
Third-Order Neurons
58
Pain Pathways
Third-Order Neurons
• Project pain information to the cortex where it
is perceived.
59
Ascending Pain Circuitry
60
Ascending Pain Circuitry
Peripheral Tissue
Damage
Spinal Cord
Peripheral Tissues
Deeper Tissues
Spinal Cord
Dorsal Root Ganglion
Nociceptors
Thermal
Stimuli
Action Potential
Chemical
Dorsal Horn
Mechanical
Myelinated A-delta Fiber
Unmyelinated C Fiber
61
Action
Potentials
Kandel, et al, Principles of Neural
Science, 4th ed., 2000, McGraw-Hill,
p.473.
62
Ascending Pain Circuitry
Pain
Brain
Thalamus
Midbrain
Brainstem
Medulla
Spinal Cord
63
Adapted From Basbaum & Fields, 1999
Descending Pain Modulation
64
Descending Pain Modulation
Pain
Brain
Thalamus
Midbrain
Brainstem
Medulla
Spinal Cord
Adapted From Basbaum & Fields, 1999
Modulation of the Pain
Experience
66
Modulation of the Pain Experience
- Only recognize pain in the thalamus and then sends it to the cortex
- This does not occur with temperature and touch
- Somesthetic cortex determines where the pain came from
- Pontine noradrenergic neurons can modify or turn on or off pain
- Serotonin can turn on (PNS) or off pain (CNS)
- At the site of the injury in the periphery, the sodium rushes into the
cell
- With chronic pain, there is an increase in the sensitivity or uptake of the
receptors of the drug
- Drugs block the sodium channels
- In the dorsal horn, the first-order neurons come in and the calcium
voltage channels and a receptor (which one?) have an increase in
the receptor
- Use drugs that block the calcium channels and receptors
- preGABA
67
Modulation of the Pain Experience
 Endogenous analgesic
center in the midbrain
 Pontine noradrenergic
neurons
 Nucleus raphe magnus in
the medulla send
inhibitory signals to
dorsal horn neurons in
the spinal cord
Pain signal  by
prostaglandins
Pain signal  by
endogenous opioids
68
Characteristics of Opioids
69
Characteristics of Opioids
- Opioids can work in the periphery, but most of them work in the
CNS
- Slow the response going up to the brain
- Opioids bind presynaptically to halt the secretion of nts, so less
information goes up the spinothalamic tract
- Then modify the pathway to decrease the pain
- Generally opioids make people sleepy, but it can make some people
agitated
- Generally they make people very happy
- Opioids can slow respiration
- Ironically they are used to decrease slowed breathing
- Opioid intoxication leads to pinpoint pupils
70
Where is Pain Perceived as a
Localized Sensation?
71
Where is Pain Perceived as a Localized
Sensation?
25% 25% 25% 25%
1. Thalamus
- Just knows that it is
pain, not touch or
temperature
2. Sensory cortex
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3. Nociceptor
4. 1st order neuron
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- Knows where the pain
comes from
Pain
Management and Assessment
73
Patient Impact
74
Patient Impact
• Pain management begins with a comprehensive
assessment
– Should determine the functional status
• The impact of pain on a patient’s ability to
function
• Pain assessment determines the treatment plan
• Goals of treatment
– Relieve pain
– Increase patient’s satisfaction
75
Pain as an Ongoing Process
76
Pain Assessment as an Ongoing Process
Assess the patient’s goals
Pain should be assessed and documented…
• At regular intervals after initiation of the treatment
plan.
• IV – 15-30 minutes later
• Oral – 60 minutes later
• With each new report of pain.
• Changes in pain patterns or the development of
new pain should trigger diagnostic evaluation
• Should not be attributed to preexisting causes
77
Pain Assessment
78
Pain Assessment
• Unidimensional assessments look at only one element of pain
– Ex. a pain scale only looks at pain severity
• Multidimensional assessments look at more elements of pain
• P = Provokes/Palliates/Previous Treatment
• Q = Quality
• R = Region/Radiation
• S = Severity
• T = Time
• U = (you) – Associated Symptoms
79
P – Provokes/Palliates/Previous
Treatment
80
P – Provokes/Palliates/Previous
Treatment
• What causes pain?
• What makes it better?
• From a nondrug perspective
• Worse?
• What treatments have you tried?
• Did the treatments work?
81
Q – Quality of the Pain
82
Q – Quality of the Pain
• What does it feel like in your own words?
• What words describe the pain?
Is it sharp or dull?
Stabbing or burning?
Crushing?
• Try to let patient describe the pain, sometimes
they say what they think you would like to
hear.
83
R – Region/Radiation
84
R – Region/Radiation
• Where is the pain?
• Is there more than one site?
• Does the pain radiate?
• Where does it radiate to?
• Did it start elsewhere and now is localized to one
spot?
85
S – Severity of the Pain
86
S – Severity of the Pain
• How severe is the pain on a scale of 1 - 10?
• Other symptoms (nausea, vision changes)
• Does the pain affect physical or social
functioning?
87
T – Timing of the Pain
88
T – Timing of the Pain
•
•
•
•
•
When did the pain start?
How long did it last?
Is the pain constant or intermittent?
How often does it occur?
Has the intensity changed since the pain
started?
89
U – (You) Associated Symptoms
90
U – (You) Associated Symptoms
• What does the pain keep you from doing?
– Sleeping
– Eating
– Affects my mood
– Cannot work
– Visit with my family
– Knit
– Ambulate to the bathroom unassisted
• What would you like to be able to do that you
cannot do now because of the pain?
91
Measuring Pain Intensity
92
Measuring Pain Intensity
A pain scale is useful for grading the intensity of pain.
 Need to use a validated tool that is easy to use
 May need to have a translator
It should…
•
•
•
•
Be easy for the patient to use.
Correlate with the patient’s cognitive level.
Be used consistently across disciplines and at each examination.
Take into consideration the following
•
•
•
•
•
Developmental stage
Chronological age
Functional status
Cognitive abilities
Emotional status
93
Assessment Tools
94
Assessment Tools

Visual Analogue Scale

Verbal Numeric Rating Scale

Written Numeric Rating Scale

Descriptive Pain Intensity Scale
 None, mild, moderate, severe

Faces Intensity Scale
 Developed for children
 Used for people who do not speak English
 Need to know the baseline for the patient

McGill Pain Questionnaire

Daily Pain Diary
 Can use a pain notebook
 Record the best, worst, and the average for every day
 Write pain rating before taking medication and one hour later
95
Pain Medications
96
Analgesics
Nonopioids
Opioids
97
WHO Analgesic Ladder
98
WHO Analgesic Ladder
 Step 1—Mild to moderate pain
• Nonopioid analgesic and adjuvant
(ex. anti-depressant)
• NSAIDS and acetaminophen
 Step 2—More severe pain
• Opioid for mild to moderate pain
• Add opioid analgesic, oxycodone,
hydrocodone (number one
dispensed drug in the country)
 Step 3—Severe pain
• Substitute opioid—morphine,
fentanyl
• May have a nonopioid and an
adjuvant
99 p.
Lehne, 2007, Pharmacology for Nursing Care, 6th ed., Elsevier,
286
Dosing Schedules for Pain
100
Dosing Schedules for Pain
Lehne, 2007, Pharmacology for Nursing Care, 6th ed., Elsevier, p. 271
101
Nonopioids
102
Nonopioids
• Topical
• Nonsteroidal anti-inflammatory drugs
(NSAIDS)
• Para-aminophenol derivatives
103
Nonopioids
Topical
104
Nonopioids
Topical
• Capsaicin (hot chili peppers):
– Secretes and eventually depletes Substance P
– Takes 2 weeks to work
– Can cause skin irritation
• Need to wash hands after use because it will burn
105
Nonopioids
Nonsteroidal Anti-Inflammatory
Drugs (NSAIDs)
106
Nonopioids
Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)
 Nonsteroidal anti-inflammatory drugs (NSAIDS) inhibit
prostaglandin synthesis and decrease the sensitivity of the
nociceptor.
– Topical
• Flexor patch
• Gel
• Drops
– Systemic
• Works locally to treat the pain and also works in the CNS
• Aspirin
• Ibuprofen and others
107
Nonopioids
Para-aminophenol Derivatives
108
Nonopioids
Para-aminophenol Derivatives
 Para-aminophenol derivatives (Acetaminophen)
– Used alone and in combination with other drugs
– Do not use acetaminiophen in someone who has liver
damage or who is an alcoholic
109
Opioids
110
Opioids
 Narcotic once referred to opium derivatives.
Narcotic is a value-laden word that should not be used with
patients—use opioid instead.
 Opioids work primarily in the CNS: forebrain,
brainstem, spinal cord.
Alters the perception of pain
Opioids bind to a transmembrane receptor (mu,kappa).
NH2
NH2
COOH
COOH
Effect
111
Opioid Drugs
Mechanism of Action
112
Opioid Drugs
Mechanism of Action
 Act at the Opioid Receptors (mu,kappa) in CNS.
 Simulate Endogenous Opioids.
• Endorphin – Mu
• The winner
• Leads to sedation
• Enkephalin - Kappa
• Dynorphin – Delta
• Not sure what delta does
 Most Potent Analgesic Compounds.
113
Opioid Drugs
Side Effects
114
Opioid Drugs
Side Effects
• The side effects are mediated by peripheral opioid
receptors located in the organs that are affected, not by
receptors in the CNS.
• Sedation
• Respiratory Depression
• Constipation
• When the opioid hits opioid receptors in the gut, it slows
peristalsis
• People have dies from fecal impaction
• Should also prescribe a stool softener
• Urinary Retention
• Orthostatic Hypotension
• Nausea/Emesis
115
Responses to Activation of Mu
and Kappa Receptors
116
Responses to Activation of Mu and Kappa
Receptors
Receptor Type
Response
Analgesia
Mu
Kappa
X
X
Respiratory depression
X
Sedation
X
Euphoria
X
Physical dependence
X
Decreased GI motility
due to slowed
peristalsis
X
Lehne, 2007, Pharmacology for Nursing Care, 6th ed., Elsevier, p. 259
X
X
117
Tolerance, Dependence, and
Addiction
118
Tolerance, Dependence, and Addiction
• Tolerance - physiological process of desensitization of
receptors  need dose increase to achieve same
degree of analgesia.
• Physical dependence – when the drug is stopped
suddenly, the patient feels negative effects
• Addiction – drug use despite harm
– Psychosocial in nature
119
Routes of Administration
120
Routes of Administration
 Intravenous
 Intramuscular
 Oral
 Try to use it if the person is not in a crisis
• Unmodified (short-acting)
• Extended release/long-acting
 Transmucosal
 Sublingual, Buccal
 Rectal
 Transdermal
121
Oral Route
122
Oral Route
Simplest and least invasive route
Minimizes burden of caregivers
Immediate- and controlled-release forms are
available
Side effects may limit the usefulness:
• Nausea and vomiting
• Decreased GI function
123
Rectal Route
124
Rectal Route
 Easy to use alternative to PO.
 Most useful in short-term and end-of-life care.
 Need a suppository
 Do not use an oral medication
 Unacceptable to some patients and family
 Aesthetics
 Rectal irritation
 Inability to retain medication
 Inferior and middle rectal veins empty into vena cava.
 Avoids first pass effect
 Superior rectal vein empties into portal vein.
 Insert rectal doses just above anal sphincter
 Interference with absorption.
 Mechanical (e.g. feces)
 Inappropriate vehicles
 Spontaneous expulsion (>10-25 ml)
125
Transdermal Route
126
Transdermal Route
 Encourages compliance
 Long-acting (every 3 or 7 days)
 Disadvantages





Toxicity may continue after removal
Release rate may vary with fever
Results may vary in cachectic (wasted) patients
Expensive
Slow process
 Best for people who have constant pain
 Difficult-impossible to titrate
 Slow onset
 Long time to steady state serum levels
 Dose conversion problems
 Fentanyl/buprenorphine
 Fentanyl is an every three day patch
127
Sublingual and Buccal Routes
(Transmucosal)
Advantages
128
Sublingual and Buccal Routes (Transmucosal)
Advantages
• Avoids first pass
• Less costly than parenteral
• Comfort for patient
• Effective in 15-25 minutes
129
Sublingual and Buccal Routes
(Transmucosal)
Disadvantages
130
Sublingual and Buccal Routes (Transmucosal)
Disadvantages
• Low Bioavailability
– Bioavailability – how much drug reaches the site
of action
• Taste
• Inconvenient with large doses
• No fluids for ≈ 15 min after dose
131
Opioid Prototypes
132
Opioid Prototypes
Class
Prototype
Agonist
- Bind to Mu receptor
Morphine Sulfate, dilaudin, methadone
Agonist/Antagonist
- Stimulate some receptors,
like Mu, but block other
receptors
Pentazocine
Opioid antagonist
-Bind to the Mu receptor
and block it
-Competitively compete with
the receptor
Naloxone
133
Morphine: Pharmacokinetics
134
Morphine: Pharmacokinetics
Absorption
IM, SC, IV (PCA): Rapid
PO: Large 1st Pass effect
Pregnancy Risk
C
Metabolism/
Excretion
Liver and Gut Mucosa
- Deals with the P450 cytochrome system
Urine and Breast milk (wait 6 hours)
Onset
PO: Variable
Studies have’ shown that the drug exerts animal teratogenic or embryocidal effects, but there are
no controlled studies in women, or no studies are available in either animals or women.
[Immediate Release (IR); Sustained Release (SR)]
IV: Rapid
Peak
PO: 1-2h
IV: 20 min
Duration
4-8 h
- Normally about 4 hours
Dose
Max dose
Varies with need and tolerance
- Start low, with about 5 mg
No ceiling (limit) with progressive dosing
135
Fentanyl: Pharmacokinetics
136
Fentanyl: Pharmacokinetics
Absorption
Transdermal patch; Transmucosal (SL or buccal lozenge, tablet,
film)
IV: anesthesia use mainly
Pregnancy Risk
C
Metabolism/
Excretion
Liver/kidney
-Metabolized to inactive drug products, which are not working
and thus are not toxic
- better for someone with end stage renal disease
Urine
Onset
Transdermal / buccal: gradual
Peak
Variable: Based on rate of absorption
Duration
48-72h
Dose
Max dose
12-100 mcg/hour with escalating doses
(multiple patches) – max 300 mcg/hour
- Cannot go from having no opioids to having a fentanyl patch
Studies have’ shown that the drug exerts animal teratogenic or embryocidal
effects, but there are no controlled studies in women, or no studies are available
in either animals or women.
137
Fentanyl Patch
Administration and Disposal
138
Fentanyl Patch
Administration and Disposal
• Wear gloves
• Apply to non-irritated skin
• No soaps/creams/ lotions that can irritate/
change skin condition
• Replace every 72 hr to new site
• Fold and flush old patch
– To dispose it, should follow the package labeling
139
Oxycodone: Pharmacokinetics
140
Oxycodone: Pharmacokinetics
Absorption
PO: IR, SR (OxyContin-only long-lasting oral oxycodone)
Pregnancy Risk
B
D
Animal studies do not indicate a risk to the fetus and there are no controlled human studies, or animal studies
do show an adverse effect on the fetus but well-controlled studies in pregnant women have failed to
demonstrate a risk to the fetus.
Positive evidence of human fetal risk exists, but benefits in certain situations (e.g., life threatening
situations or serious diseases for which safer drugs cannot be used or are ineffective) may make use of the
drug acceptable despite its risks.
Metabolism/
Excretion
Liver
Urine T ½: 2-3h
Onset
15-30 min
Peak
1-1.5h
Duration
3-6h
Dose
Max dose
•Alone-no ceiling (limit) with progressive dosing.
•With ASA/acetaminophen 325/500 mg (Percodan / Percocet): dose
limited by ASA/acetaminophen.
•maximum dose of percocet is limited by the 4 grams of acetimenophen
141
OxyContin
142
OxyContin
Convenient 12 hour dosing
Available in multiple strengths: 10 - 80 mg
Schedule II opioid, by prescription only
One prescription only with no refills
Tablets MUST be taken whole, not crushed, broken,
or chewed
Extended release drug
Contraindications similar to other opioids
143
Pentazocine
144
Pentazocine
Absorption
PO: Large First Pass Effect
SQ, IM
Pregnancy Risk C
Studies have’ shown that the drug exerts animal teratogenic or embryocidal effects, but there are no
controlled studies in women, or no studies are available in either animals or women.
Metabolism/
Excretion
Liver
Urine
MOA
Agonist: Kappa
Antagonist: Mu
- Tries to limit respiratory depression
Tablets contain naloxone to prevent abuse by IV
injection—naloxone is destroyed on 1st pass
Special notes




IV: ICP
Pts taking other opioids:
Reverses Mu opioid  pain
May precipitate withdrawal
145
Naloxone
146
Naloxone
Class
Pure Opioid Antagonist
Therapeutic use
Respiratory depression following narcotic overdose.
Pregnancy Risk
B caution with lactation
MOA
Reverses
effect
byfetus
competing
receptor
Animal studiesnarcotic
do not indicate
a risk to the
and there are at
no controlled
human sites.
studies, or
Onset
IV: 1-2 minutes
Duration
1-4 hours
Note
Duration of narcotic usually > naloxone
- May have to give a repeat dose to prevent overdosing on
the opioids
animal studies do show an adverse effect on the fetus but well-controlled studies in pregnant
women have failed to demonstrate a risk to the fetus.
147
Equianalgesic Opioid Dosing
148
Equianalgesic Opioid Dosing
• The idea is that the effects of the medications
in the table are all equal
• Gets at the potency issue
– Need more of certain drugs in order to have the
same effect
149
Equianalgesic Opioid Dosing
Drug
Equianalgesic Dose (mg)
Parenteral
Oral
Morphine
10
30
Buprenorphine
0.3
0.4 (sl)
Codeine
100
200
Fentanyl
0.1
NA
Hydrocodone
NA
30
Hydromorphone
1.5
7.5
Meperidine
100
300
Oxycodone
10*
20
1
10
100*
120
Oxymorphone
Tramadol
*Not available in the US
McPherson ML. Demystifying Opioid Conversion Calculations: A Guide For Effective Dosing. Amer Soc
of Health-Systems Pharm, Bethesda, MD, 2010. Copyright ASHP, 2010.
Used with permission. NOTE: Learner is STRONGLY encouraged to access original work to review all
caveats and explanations pertaining to this chart.
Evaluating Opioid Effects
151
Evaluating Opioid Effects
 Pain Rating (at rest and with movement)
 Patient pain goal
 Respiratory rate: must be at least 10/min
 Sedation Score
 0 None
 1 Mild, occasionally drowsy, easy to arouse
 2 Moderate, frequently drowsy, easy to arouse
 3 Severe, somnolent, difficult to arouse
 S Sleep, normal sleep, easy to arouse
 The most that you want someone to be if you are giving
an opioid is a two
 Adverse Effects/Management of adverse effects
 Respiratory depression, sedation, constipation nausea/vomiting,
itching
 Patient Satisfaction with pain management
152
Opioids
Managing Adverse Effects
153
Opioids
Managing Adverse Effects
Adverse Reaction
Drug/dose
Sedation/Respiratory
Depression
• Naloxone
• Monitor pt continually
Nausea/Vomiting
Antiemetics (to be covered in GI)
Itching
•Switch to a new opioid (esp. if on morphine)
•Diphenhydramine 25-50 mg IV/po q6h
•Local application of ice to any place on body
•Can give histamine
Constipation
•Bowel protocols: softeners + peristaltic
stimulators + fluids + mobility
•Start protocol as soon as taking PO
•Methylnaltrexone
154
Opioid Overdose
155
Opioid Overdose
Assessment
Intervention
Respirations
<10
•Initial dose 0.4-2mg naloxone IV
•Repeat q 2-3 min if no respiratory
response
•If no effect after 10 mg, consider
other causes of respiratory decrease
•Airway/Life support as needed
•Vasopressors
•Life support
Severe
Hypotension
156
Oxycodone Preparations Percocet
and Percodan Have Which of the
Following Problems?
157
Oxycodone Preparations Percocet and
Percodan Have Which of the Following
Problems?
A
ce
Th
ey
n
he
ta
m
in
op
ar
e
an
d
en
ex
p
ry
ve
no
t
ar
e
ey
Th
...
...
ef
fe
...
io
av
rb
po
o
e
ha
v
ey
si
ve
25% 25% 25% 25%
Th
1. They have poor
bioavailability
2. They are not very
effective
3. They are expensive
4. Acetaminophen
and aspirin in the
tablet limit the
dose
When Administering Naloxone for
Opioid Overdose, Which of the
Following Must We Remember?
159
When Administering Naloxone for Opioid
Overdose, Which of the Following Must We
Remember?
sh
It
ha
s
a
es
ca
us
It
...
or
t
ha
us
ea
na
or
al
is
It
lflif
e
ac
ly
pe
n
ex
s
It
i
an
d.
..
tiv
si
ve
1. It is expensive
2. It is orally active
3. It causes nausea and
vomiting
4. It has a short halflife compared with
most opioids
e
25% 25% 25% 25%
Opioid Administration
by PCA Pump
161
Opioid Administration
by PCA Pump
Patient-controlled analgesia (PCA)
162
Components of PCA
163
Components of PCA
• PCA device
• The drug
164
Components of PCA
PCA Device
165
Components of PCA
PCA Device
• The PCA device: An electronically controlled infusion pump
that delivers a preset IV bolus of opioid analgesic when the
patient pushes a button.
– The prescriber decides how much drug the patient will get when
he or she hits the button
• The device will only deliver the bolus if an appropriate
interval (the lock-out interval) has elapsed since the last
bolus.
• Some devices will deliver a basal infusion with the patientcontrolled bolus delivered on top of the basal rate.
166
Components of PCA
The Drug
167
Components of PCA
The Drug
• Pure opioid agonists are used, most frequently
morphine, but sometimes others (fentanyl,
methadone, hydromorphone).
• Agonist-antagonists can also be used.
168
PCA Decision Algorithm
169
PCA Decision Algorithm
No
Pain goal met/Pt satisfied?
Yes
Continue Plan
# attempts/ # injections (doses)
Pt receiving
max dose/hr?
No
Terms:
Dose: Amount/ “click”
Delay/lockout: Time
between doses
Dose/hour
Yes
Call MD
Assess reasons
for not using
+
Pt education
Re-evaluate
170
Nursing Process for Opioid
Administration
171
Nursing Process for Opioid Administration
Assessment
• Sudden
pain post invasive procedure
• Check VS before giving med
Nsg diagnoses
• Pain due to incomplete management
• Risk injury due to adverse effects
• Constipation due to opioid meds
Planning/Intervention: • As previously discussed
Max. therapeutic
• Do not give agonist/antagonist if
effects
started opioid
Planning/Intervention
Minimize adverse
effects
• Give PO with food due to nausea and
vomiting
• Mobility to prevent paralytic ileus
(absence of peristalsis)
• Encourage deep breathing & coughing
post operatively
172
Pharmacological Interventions
173
Pharmacological Interventions
Right dose provides effective analgesia with
minimal side effects.
By the ladder, by the clock, by the least invasive
route.
Titrate (Evaluate effect & change med/dose) to
effective pain control.
PRN
174
Opioids
Patient and Family Education
175
Opioids
Patient and Family Education
• Drug information
• Do not ever let a family member do proxy dosing
– The patient needs to be alert enough and under control
enough in order to push the button
• Assess ability to safely self-medicate post discharge
• Avoid alcohol and other CNS depressants
• Long term use (3 months) require
gradual dose reduction to avoid withdrawal
• Environmental and lifestyle safety
• Wear a medical alert device
176
Opioids
Fears and Misconceptions
177
Opioids
Fears and Misconceptions
• RESPIRATORY DEPRESSION
– Do get some tolerance after about one week but need to be careful
of
tolerance
• DEPENDENCE
• TOLERANCE
• ADDICTION
– Continued use despite harm
178
Addiction vs. Effective Pain
Management
179
Addiction vs. Effective Pain Management
 Addiction is a psychological process related to craving,
obtaining and compulsive use of substance for "mood
altering“ effect regardless of negative physical, legal and
social consequences
– If function/relationships deteriorate, this is a sign of addiction
 Effective Pain Management:
– If function/relationships improve this is a sign of effective pain
management
 Contributing Reinforcer:
– Pain is a reinforcer in Pain Management
– Discomfort of withdrawal is a reinforcer in Addiction
180
Opioid Administration
Legal Aspects
181
Opioid Administration
Legal Aspects
• Accurate documentation of drug &
dose given; wasted drug
witnessed.
• Narcotic count accurate.
182
Nonopioid Adjuvants
183
Nonopioid Adjuvants
• Tricyclic antidepressants Block Noradrenaline and
serotonin reuptake decreased Substance P
release
• Anticonvulsants decrease nerve conduction
• Steroids Stabilize mast cells decrease
histamine and decrease swelling
184
Nonpharmacologic Strategies
Cortex-Focused
185
Nonpharmacologic Strategies
Cortex-Focused
• Relaxation
• Distraction
• Imagery
• Music
186
Nonpharmacologic Strategies
Local/Regional
187
Nonpharmacologic Strategies
Local/Regional
•
•
•
•
Touch: Human Connection
Energy therapy
Heat (increase circulation)
Cold (decrease swelling and nerve
excitation)
• Massage
• Acupuncture
• Transcutaneous Electrical
Nerve Stimulation (TENS)
188
Placebos and the Placebo Effect
189
Placebos and the Placebo Effect
 Placebos
 Inactive or partial dose products
 Deception involved (OK for research
with informed consent)
 The "Placebo Effect”: achieve therapeutic
result with administration of a placebo
 BUT the Nurse-Patient relationship is built on honesty
and trust. Therefore the administration of placebos to
deceive a patient is UNETHICAL !!!!
(American Society of Pain Management Nurses)
190
Patient Education
191
Patient Education
DO NOT CHASE PAIN !!!
Do not wait to see how the pain develops
Teach pt how to use Pain Scale!!!
Anticipate fear/reluctance to take opioids.
• Establish pain rating to ask for pain med/press PatientControlled Anesthesia (PCA).
• No need to “save” meds until pain gets worse.
192
Evaluation Outcomes
193
Evaluation Outcomes
 Patient sets pain rating goal—usually <3 at rest, 6 with
movement.
 Engages in ADL’s as possible.
 Self-medicates appropriately to attain goal.
 Maximum pain relief with minimal side effects.
 Able to focus attention away from pain.
194
Things to Look Up or Ask
• Slides 60-63 – ascending pain circuitry
• Slides 64-65 – descending pain modulation
• Slides 66-68 – modulation of the pain
experience
• Slide 154 – is there still constipation if you
take opiods IV rather than oral?
195