For students

1. Pain management

2. Objectives
• Describe types of pain
• Explain the mechanisms involved in pain
transmission
• Select an appropriate method of pain
assessment
• Recommend an appropriate choice of
analgesic, dose, and monitoring plan
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3. Definition
• Pain is an unpleasant, sensory and emotional
experience associated with actual or potential
tissue damage or described in terms of such
damage.
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4. Pain classification
Classification based on pain pathophsiology
• Nociceptive Pain
– Somatic (arising from skin, bone, joint, muscle,
or connective tissue)
– Visceral (arising from internal organs such as the
large intestine or pancreas)
• Neuropathic pain
– Postherpetic neuralgia
– Diabetic neuropathy
• Cancer pain
– Pain related to the disease itself &/or treatment
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5. Pain classification…
• Classification bases on duration of pain
– Acute pain: pain of sudden onset, usually
subsides in a short period of time
– Chronic pain: pain lasting 1-3 months or longer
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6. Pain classification…
Acute pain
• Pain caused by noxious stimulation due to:
– Injury (posttraumatic, postsurgery)
– A disease process (acute medical illness such as MI,
pancreatitis, and renal calculi)
– Abnormal function of muscle or viscera
• Acute pain can be:
– Somatic pain: localize directly to the site of injury
– Visceral pain: diffuse, poorly differentiated, referred
pain
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7. Pain classification…
Chronic pain
• May be due to nociception in which
psychological and behavioral factors often play
a major role.
• Chronic pain can be:
– Chronic malignant pain (pain associated with a
cancer)
– Chronic nonmalignant pain (rheumatoid arthritis,
osteoarthritis, pain originating in nerve tissue etc)
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8. Characteristics of Acute and Chronic Pain
Characteristic Acute Pain Chronic Pain
Relief of pain Highly desirable Highly desirable
Organic cause Common May not be
present
Environmental/family
issues
Small Significant
Psychological component Usually not present Often a major
problem
Depression Uncommon Common
Insomnia Unusual Common
component
Treatment goal Cure Functionality
Dependence and
tolerance to medication
Unusual Common
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9. Pain pathway
• Tissue injury→ release of bradykinins, K+,
prostaglandins, histamine, leukotrienes,
serotonin, and substance P
• Stimulation of free nerve endings
(nociceptors) by mechanical, thermal, and
chemical factors
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10. Pain pathway…
• Receptor activation leads to action potentials
that are transmitted along afferent nerve
fibers to the dorsal horn of spinal cord.
• Endogenous opioids (Enkephalins, dynorphins,
and β-endorphins) bind to opioid receptors (
μ, δ, κ) and modulate the transmission of pain
impulses
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11. Pain pathway…
• .
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12. Clinical presentation
Symptoms
• Acute pain
– Sharp or dull, burning, shock-like, tingling,
radiating, fluctuating in intensity, varying in
location, and occurring in a timely relationship
with an obvious noxious stimulus.
• Chronic pain
– Similar to acute pain and over time presentation
may change (sharp to dull, obvious to vague).
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13. Clinical presentation…
Signs
• Acute pain
– increased BP, tachycardia, diaphoresis, mydriasis,
and pallor.
• Chronic pain
– Neuroendocrine responses are usually absent
– Comorbid conditions (Appetite, Sleep and
affective disturbances) often present.
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14. Pain assessment
• Appropriate assessment of pain severity is
extremely important to determine proper
treatments and evaluate the efficacy of
treatments.
• Self-reporting by patients is the most reliable
indicator of the existence and intensity of
pain.
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15. The most reliable indicator of the existence of
pain and its intensity is the patient’s description.
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16. Characterizing Pain
Onset and duration When did pain begin and how long
has it been since the pain began?
Palliative factors What makes the pain better?
Provocative factors What makes the pain worse?
Quality Describe the pain
Location Where is the pain?
Severity/intensity How does this pain compare with
other pain you have experienced?
Temporal factors Does the intensity of the pain change
with time?
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17. Pain assessment tools
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18. ABCDE of pain management
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19. Pain management
Goals of therapy
• Relieving pain, and providing reasonable
comfort at the lowest effective analgesic dose
• Maintaining patient function, and maximizing
the patient’s quality of life.
• Rehabilitation and resolution of psychosocial
issues.
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20. Pain management options
• There is a lot we can do to relieve pain!
– Analgesic drugs
– Non-drug strategies
– Patient and caregiver
education and support
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21. Non pharmacologic therapies
• Cognitive–Behavioral Therapy
– Relaxation
– Imagery
• Exercise
• Physical methods
– Massage
– Heat or cold applications
• Transcutaneous Electrical Nerve Stimulation
(TENS)
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22. Patient & care giver education
• Diagnosis, prognosis, natural history of
underlying disease
• Assessment of pain
• Explanation of non-drug strategies
• Explanation of drug strategies
• Management of potential side-effects
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23. Analgesic Drugs
• Acetaminophen
• NSAIDs
– Non-selective COX inhibitors
– Selective COX-2 inhibitors
• Opioids
• Others
– Antidepressants
– Anticonvulsants
– Local anesthesia
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24. Pain management…
• Do Not Use Placebos!
– Unethical in clinical practice
– They don’t work
– Not helpful in diagnosis
– Leads to mistrust
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25. Pain management…
• Neuropathic pain syndromes respond to
unconventional analgesic drugs such as TCAs,
and anticonvulsants.
• The elderly and the young are at a higher risk
for under treatment of pain because of
misunderstanding/communication.
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26. 26

27. 27

28. WHO Analgesic ladder
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29. Adult dosing guidelines for analgesics
Aspirin 325–1,000 mg q 4–6 h
Acetaminophen 325–1,000 mg q 4–6 h
Diclofenac 100, 50mg q 8 h
Ibuprofen 200–400mg q 4–6 h
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b

30. 30

31. 31

32. Major Adverse Effects of the Opioid Analgesics
Effect Manifestation
Mood changes Dysphoria, euphoria
Somnolence Sedation, inability to concentrate
Stimulation of
chemoreceptor trigger zone
Nausea, vomiting
Respiratory depression Decreased respiratory rate
Decreased gastrointestinal
motility
Constipation
Increase in sphincter tone Biliary spasm, urinary retention (varies
among agents)
Histamine release Urticaria, pruritus, rarely exacerbation
of asthma (varies among agents)
Tolerance Larger doses for same effect
Dependence Withdrawal symptoms upon abrupt
discontinuation 32

33. Evaluation of therapeutic outcome
• Pain intensity, pain relief, and medication side
effects must be assessed on a regular basis.
• The timing and regularity of assessment
depend on the type of pain and the
medications administered
• Side effects associated with analgesic
medications should be managed properly
– E.g constipation –prevent by proper intake of
fluids and fiber use of stimulating laxative
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34. Problems with pain management
• Poor training of healthcare practitioners in
pain assessment and management
• Improper patient education
• Inadequate communication among healthcare
professionals
– Misunderstanding of opioid tolerance, physical
dependence, addiction, and pseudoaddiction
causing clinicians to misjudge and mistreat pain.
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35. Assignments
1. Pain management in cancer patients
2. Pain management in pediatric patients
3. Adjuvant analgesics (antidepressants and
anticonvulsants) in chronic pain management
[review of primary literatures]
4. Drug therapy problems with NSAID use
(Contraindications, drug interactions, adverse
drug reactions etc.)
5. Opioid tolerance, dependence, addiction, and
pseudoaddiction and its management
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36. Case study
• Chief Complaint
"The pain in my hips was bad, but this pain in my feet is really different.
The medication doesn't seem to make a difference."
• HPI
R.A is 65-year-old woman who has had a 15-year history of
osteoarthritis, primarily affecting her hips and knees. She has
frequent complaints of joint pain after walking or other activities and
experiences stiffness in the morning when she awakes. Recently, she
has had difficulty walking and has had several near falls. She states
that her feet feel very heavy and feel numb and tingly. She describes
the feeling as like pins and needles.
• PMH
Type 2 diabetes mellitus x 10 years, HTN x 15 years, Osteoarthritis x
15 years
• Meds
– Aspirin 325 mg po once daily
– Lisinopril 20 mg po once daily
– Glyburide 10 mg po BID x 2 years
– Acetaminophen 500 mg 2 tablets po BID
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37. • All
Meperidine bronchospasm, hives; PCN allergy as a child; ibuprofen GI
intolerance
• ROS
Positive for mild to moderate hip pain. Tingling and numbness in feet—
reports 8 out of 10 level of discomfort. No other complaints.
• Physical Examination
– VS
BP 104/72, P 72, RR 15, T 37.4°C; Wt 68 kg, Ht 1.56 m
– MS/EXT
Both hips tender to palpation; right hip pain with flexion >90° and with
internal and external rotation >45°; diminished hair growth on toes, and
reduced peripheral pulses in lower extremities
– NEURO
CN II–XII intact, A & O x 3; diminished ankle and knee jerks, decreased
sensation to monofilament testing and decreased vibratory sensation
• MRI of Spine
Slight degenerative disc disease; no evidence of spinal stenosis or
herniated disc 37

38. 38
Labs.
Na 144 mEq/L ALT 15 IU/L
K 3.9 mEq/L AST 30 IU/L
Cl 103 mEq/L CBC and diff: WNL
Ca 9.8 mg/dL Alk phos 182 IU/L Alb 3.8 g/dL
CO2 31 mEq/L T. bili 0.2 mg/dL T.prot 8.1 g/dL
SCr 1.6 mg/dL Glu 53 mg/dL (fasting)
BUN 16 mg/dL A1C 7.0%
Assessment
Diabetic peripheral neuropathy
Chronic mild–moderate hip pain due to osteoarthritis
Type 2 diabetes mellitus
HTN—controlled

39. Questions
• Problem Identification
1. Create a list of the patient’s drug therapy problems.
2. What information indicates the presence or severity of chronic
nonmalignant pain?
• Goal of therapy
3. What are the goals of pharmacotherapy in this case?
• Therapeutic Alternatives
4. What nondrug therapies might be useful for this patient?
5. What pharmacotherapeutic alternatives available for treatment of
this patient’s pain.
• Outcome Evaluation
6. What clinical and laboratory parameters are necessary to evaluate
the therapy for achievement of the desired therapeutic outcome
and to detect or prevent adverse effects?
• Patient Education
7. What information should be provided to the patient to enhance
compliance, ensure successful therapy, and minimize adverse
effects?
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40. • CLINICAL COURSE
• The physician selected to use gabapentin at the
recommended initial dosing of 300 mg po TID. At
her 2-week follow-up appointment the patient
reported some pain relief but new complaints of
dizziness. She describes the pain in her feet as 6
on scale of 1–10. Her hip pain is bearable and
does not affect her activities.
• FOLLOW-UP QUESTIONS
• 1. Based on this new information, how would you
alter your treatment plan?
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