This document discusses pain assessment and management. It provides an overview of different pain scales used to assess intensity, location, quality and other factors. It reviews opioid pharmacology including delivery methods, side effects like constipation and nausea/vomiting, and challenges to pain management like barriers to treatment. Common chronic pain syndromes like cancer, low back pain and osteoarthritis are examined in terms of characteristics, diagnosis and treatment considerations.

1. On Pain: Taking the pain out of pain management
Suzana Makowski, MD MMM FACP
Palliative Care
UMassMemorial/UMassMedicalSchool

2. Overview
• Pain assessment review
• Opioid pharmacology: what I wish I had known...
• Pain syndromes

3. • Intensity
Assessing pain: • Location
• Quality: Nociceptive/Neuropathic
The easiest pain to tolerate is someone else’s • Timeline
• Alleviating/Exacerbating factors

4. Pain Intensity
• Visual analogue scale: No pain-------------------------Worst pain
• Numeric scale: 0 - 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10
• Categorial scale: mild (1-3) - moderate (4-6) - severe (7-10)
• FACES scale:
• PAID-AD scale:

5. PAINAD Scale: for non-verbal patients with
dementia

6. Pain Assessment: Timeline
Intensity
Time

7. Challenges to pain assessment
• Acute vs. chronic pain • Dependence
• Concerns about addiction and • Tolerance
abuse/misuse
• Addiction
• What else?
• Pseudoaddiction

8. Barriers to Pain Management
Physician-Related
• Limited knowledge of pain pathophysiology and assessment skills
• Biases against opioid therapy and overestimation of risks
• Fear of regulatory scrutiny/action
Patient-Related
• Exaggerated fear of addiction, tolerance, side effects
• Reluctance to report pain: stoicism, desire to “please” physician
• Concerns about “meaning” of pain (associate increased pain with worsening disease)
System-Related
• Low priority given to pain and symptom control
• Limits on number of Rxs filled per month & number of refills allowed
• Reimbursement policies
(American Pain Society, 2001; Glajchen, 2001; Lister, 1996; Portenoy RK, 1996; Weinstein et al, 2000)

9. Racial & Ethnic Barriers
• Language or cultural differences make pain assessment more difficult
• Physiciansʼ perceptions and misconceptions:
✴minority-group patients have fewer financial resources to pay for
prescriptions
✴higher drug-abuse potential among minority groups
• Patients’ lack of assertiveness in seeking treatment
• Lack of treatment expertise at many sites at which minority-group patients
are treated
• Relative unavailability of opioids in some communities
(Bonham, 2001; Glajchen, 2001)

10. Untreated pain can lead to worsening chronic pain
• In chronic pain, the nervous system remodels continuously in
response to repeated pain signals
• nerves become hypersensitive to pain
• nerves become resistant to antinociceptive system
• If untreated, pain signals will continue even after injury resolves
• Chronic pain signals become embedded in the central nervous system

11. Chronic Pain Syndromes: Cancer, Chronic Low Back Pain, Osteoarthritis,
Fibromyalgia

12. Cancer pain
Highly prevalent:
• 30-50% in active treatment
• 75-90% in advanced illness
Principles of Assessment
Pain History
• chronicity
• intensity and severity
• pathophysiology and mechanism
• tumor type and stage of disease
• pattern of pain and syndrome
Physical and Neurologic Examination
Radiographic Findings

13. Cancer Pain Treatment considerations
Identify the cause of the pain
• Primary treatment if indicated
• WHO ladder combined with etiology-specific therapies for syndromes
✴pharmacologic and nonpharmacologic interventions
✴long-acting + short-acting opioids
✴adjuvant medications for neuropathic pain
✴NSAIDs and steroids can be helpful when there is an inflammatory
component to pain

14. WHO guidelines
• Step 3: Opioid for moderate
to severe pain
+/- adjunctive treatment
+/- non-opioid
Pain Persists
• Step 2: Opioids for mild to
moderate pain
+/- adjunctive treatment
+/- non-opioid
Pain Persists
• Step 1: Non-opioid
+/- adjunctive treatment
(Adapted from Portenoy et al, 1997)

15. Chronic Low Back Pain
• 60-85% lifetime prevalence
Clinical Characteristics
• Preoccupation with pain
• Consistently disabled from
pain
• Depression and anxiety are
common
• High incidence of psychiatric
diagnoses
• Drug misuse is common, but
addiction relatively rare

16. Low-Back Pain Treatment Considerations
• Analgesic Medications
• Adjuvant Analgesics
• Physical Therapy Approaches
• Neural Stimulation
• Psychologic Management
• Multidisciplinary Pain Centers

17. Osteoarthritis
• Affects over 80% of people over 55
• 23% have limitation of activity
Diagnosis
• History: age, functionality, degree of pain, stiffness, time of occurrence
(e.g., morning, at rest, during activity)
• Physical examination: range of motion, tenderness, bony enlargement
of joint
• Laboratory findings: radiograph, CBC, synovial fluid analysis

18. Osteoarthritis Treatment Considerations
• After comprehensive assessment of function and pain
Mild to moderate pain Acetaminophen
Moderate to severe pain COX-2 and NSAIDs
Severe arthritic pain (unresponsive
to non-opioid, or for elderly at risk Opioids
for renal insufficiency)
Drug therapy ineffective or
Surgery
debilitating pain/function

19. Pain treatment
• Pharmacotherapy
• Rehabilitative Approaches
• Psychologic Interventions
• Anesthesia/Interventional Pain Approaches
• Neurostimulatory Techniques
• Radiotherapy
• Surgery
• Complementary/Alternative Approaches
• Lifestyle Changes

20. Opioids
• Pure (Full) Agonists: Preferred for Chronic Pain
• Bind to opioid receptor(s)
• No antagonist activity
• No ceiling effect
• Agonist-Antagonists
• Ceiling effect for analgesia
• Can reverse effects of pure agonists
✴ mixed agonist-antagonists (butorphanol,
✴ nalbuphine, pentazocine, dezocine)
✴ partial agonists (buprenorphine)
• Antagonists
• Reverse or block agonist effects of pure opioids
• Naloxone has been used to treat opioid overdose, addiction

21. Oral Opioids
Short-acting Long-acting
Hydrocodone/APAP
Transdermal fentanyl
Oxycodone +/- APAP
methadone
Morphine
morphine ER
Hydromorphone
oxycodone ER
Oral transmucosal fentanyl
Cmax ~ 45 min
Cmax and T1/2 vary based on
T1/2 ~ 4 hours
formulation and drug
Except fentanyl

22. Opioid pharmacology
• Conjugated in liver
• First pass metabolism
• Excreted by kidney (90-95%)
• First order kinetics

23. First order kinetics of opioids
6-7 min 15-20 min 45-60 min

24. Opioid pharmacology
• Conjugated by liver
• 90-95% excreted in urine
• Dehydration, renal failure, severe hepatic failure
• Decrease interval/dosing size
• If oliguria/anuria
• STOP routine dosing (basal rate) of morphine
• Use ONLY PRN

25. Delivery of opioids
What is the half life (range) for opioids?
2-4 hours
How many half lives to get to steady state?
4-5
What do you base your scheduled dosing on: Cmax or T1/2?
T1/2
What do you base your breakthrough dosing on:
Cmax or T1/2?
Cmax

26. Scheduling oral short-acting opioids
• Scheduled dosing based on t1/2
• Q4 hours
• PRN dosing based on time to Cmax
• Can be as frequent as Q1 hour PRN
• Adjust scheduled dose daily based on prn use

27. Scheduling long-acting opioids
(except methadone)
• Reason for use:
• Improve compliance, adherence
• Dose q8, q12, q24 hours (depending on product)
• Don’t crush or chew
• May use time-release granules (Kadian)
• Adjust dose every 2-4 days (once steady state is reached.)

28. Side effects of opioids
Common Uncommon
Bad dreams/hallucinations
Constipation* Delirium
Dry mouth Myoclonus
Nausea/Vomiting Seizures
Sedation Pruritus, urticaria
Sweats Respiratory suppression
Urinary retention
*No development of tolerance

29. Opioid side effects: Constipation
• Stimulant laxative:
• Senna, bisacodyl, glycerine, etc.
• Stool softener
• Docusate
• Prokinetic agent
• Metoclopramide
• Osmotic laxative (from above or below)
• Specific to peripheral opioid receptors
• methylnatrexone

30. Opioid side effects: Nausea/Vomiting
• Onset with start of opioids, tolerance may develop
• Mechanism: dopamine receptors and decreased motility
• Prevent or treat with dopamine-blocking anti-emetics (avoid with
long-QT):
• Haloperidol 0.5-1mg every 6 hours
• Droperidol 0.625 mg (PACU order set)
• Metoclopramide 10mg every 6 hours
• Alternative opioid if refractory

31. Opioid side-effects: Sedation
• Onset with start of opioids
• Distinguish from exhaustion due to pain*
• Tolerance develops within days
• Complex assessment in advanced disease
• If persistent, may consider alternative opioid or route of
administration
• Psychostimulants may play a role as well
• Methylphenidate 5mg qAM and 1 noon

32. Opioid side-effects: Neuroexcitability
• Presentation
• Cognitive changes: CAM assessment Reason to avoid “titrate
to comfort” order at end-
• acute onset or fluctuating course, of-life
• inattention,
• disorganized thinking/altered level of consciousness
• Restlessness, agitation
• Can cause hyperalgesia
• Myoclonic jerks, seizures (may be repressed if on benzodiazepines)
• More common in renal failure
• Mechanism:
• Morphine/hydromorphone 6-glucoronide build-up
• Management:
• Benzodiazepines, fluids, and perhaps dialysis - antipsychotics
exacerbate symptoms

33. Opioid side-effects: respiratory depression
• Opioid effects differ among patients
• Change in LOC occurs before respiratory suppression
• Pharmacologic tolerance develops rapidly
• Most studies of respiratory depression in opioids looked at patients
with drug overdose
• Management:
• Identify and treat contributing causes
• Reduce opioid dose and observe
• If unstable vital signs:
• Naloxone 0.1-0.2 mg IV q 1-2 min

34. Summary
• Treat pain as though it were your own:
✴remember under/untreated acute pain can lead to severe chronic pain
• Schedule routine opioids based on half-life
• Consider offering prns based on Cmax:
✴IV=6-12 min;
✴SQ=20-30min;
✴PO=45-1hour
• When ordering opioids, always order bowel regimen to avoid constipation
• Watch for neurotoxicity in renal insufficiency - especially at end-of-life