20 - Chronic Non-Cancer Pain

Question 1

Definition of acute, subacute, and chronic pain

Answer 1

• Acute pain: a sx that plays a functional role in body defenses and resolves w/ tissue recovery (< 2 weeks)
• Subacute pain = 2-12 weeks
• Chronic pain: no such functional role, doesn’t resolve w/ tissue recovery, and can be a primary diagnosis
• • Involves complex CNS signaling that can be amplified by stressors

Question 2

Define sensitization, allodynia and hyperalgesia

Answer 2

• Sensitization: activity is generated by nociceptors during inflammation => increased excitability of nerve cells (ie: a fire alarm sounds continuously or frequent false alarms)
• Allodynia: normally non-painful stimulus is perceived as pain
• Hyperalgesia: increased pain intensity in response to the same noxious stimulus (ex: moderate pressure causes severe pain)

Question 3

Goals of therapy for chronic non-cancer pain

Answer 3

• Pain reduction (ideal = 30-50%; realistic = 20%)
• Increased mobility
• Exercise, sleep, QOL
• Improved mood
• Minimal SE, cost, and pill burden

Question 4

Analgesic comparisons for chronic non-cancer pain

Answer 4

Pain improvement for OA from lowest to highest:
- Acetaminophen
- Tramadol
- Topical NSAIDs
- Opioids
- Glucosamine
Function improvement from lowest to highest:
- Topical NSAIDs, acetaminophen, and glucosamine
- Opioids and tramadol

Question 5

What to do w/ subacute pain

Answer 5

• Reinforce self-care and return to usual activities/ exercise
• Reassess response to pharm and non-pharm therapies
• If opioid continuation considered, assess abuse risk potential
• Assess for comorbidities that cause or increase pain

Question 6

6 A’s of opioid therapy

Answer 6

• Analgesia
• Activity
• Adverse effects
• Affect (mood)
• Accurate records
• Aberrant behaviour/ abuse risk

Question 7

Abuse and diversion risk

Answer 7

• Utilize an opioid risk assessment tool +/- an opioid contract/ agreement
• Be pt-centered and firm from the start (you and the physician)
• • Visit doesn’t equal refill
• • Inform pt of exit strategy if goals aren’t achieved (reach agreement that once you reach a certain dose you won’t increase it and will actually taper off)
• • Breach of contract is serious
• Small fills at shorter durations
• Enquire about recovery and disposal if opioid no longer used

Question 8

Describe the “affect” of opioid therapy

Answer 8

Consider pain w/ -> depression, anxiety, or sleep disturbance; substance abuse or personality disorder; comorbid general medical condition

Question 9

Pharm options for chronic low back pain

Answer 9

• Muscle relaxants (cyclobenzaprine) -> only if spasms involved; 7-14 days max
• Acetaminophen -> no better than placebo (good chance for deprescribing)
• Oral NSAIDs -> few studies show equivalent to opioids
• TCAs -> same as placebo
• Gabapentin -> only use if sciatica along w/ low back pain; caution w/ substance abuse hx & high-risk opioid score b/c high street value
• Epidural corticosteroids -> if sciatica
• Goal = use relatively passive modalities (drugs) to support active rehabilitation

Question 10

Non-pharm therapies for chronic low back pain **important

Answer 10

• Heat, massage, yoga, exercise
• Physiotherapy
• Multidisciplinary programs

Question 11

Opioid-induced hyperalgesia (OIH)

Answer 11

• Can reach a point where the dose of the drug is too high and is causing sensitization
• Unknown cause
• Ends up making the px pain worse
• Typically occurs when px are on opioids for a long time and dose has been escalating
• Only cure is to completely taper the opioid dose
• Red flag = multiple dose increases in a short period of time that isn’t helping pain or making it worse

Question 12

Opioid adverse effects

Answer 12

• Short term -> sedation, nausea, dizziness, itchiness, dry mouth
• Long term -> constipation, dependence, tolerance
• Opioid induced hyperalgesia
• Unintentional overdose
• Most are dose-related
• 80% of px will have at least 1 SE, so counselling is very important

Question 13

When should we be concerned w/ opioid use?

Answer 13

• Daily doses >/ 100 mg morphine equivalents associated w/ up to a 9-fold increase in overdose and 2-fold increase in opioid-related death compared to low doses
• When treating chronic pain, dose escalation hasn’t been proven to reduce pain or increase function, but can increase risks

Question 14

Opioid trials

Answer 14

• Start off w/ codeine or tramadol for 2 weeks then re-assess pain and function; prn or regular use?
• If no/minimal improvement, can:
• • Stop opioids all together
• • May consider a short trial of a strong opioid (increase dose q1-2weeks as tolerated)
• *Make sure an exit plan is in place from the start

Question 15

Guiding principles (NOUGG) Canadian

Answer 15

• “Opioids produce a graded analgesic response -> pt experiences the greatest benefits at lower doses and a plateauing of analgesic response at higher doses”
• Response less likely if minimal improvement after 2-3 dose increases
• “Px who receive high opioid doses and remain incapacitated by pain should be considered tx failures, even if the opioid “takes the edge off” the pain”

Question 16

Opioid tapering

Answer 16

• Educate about why (the purpose), what you are doing (physiological principles), and how (the process)
• • Help pt get better -> eliminate source of abuse (if present), reduce withdrawal-mediated pain at higher doses, reduce hyperalgesia, healthier perception of pain experience due to improved mood and energy
• Emphasize that the process ideally needs to go in one direction, even if it takes awhile
• If you taper slow enough, the body doesn’t even notice so pt shouldn’t experience withdrawal or increased pain

Question 17

What should be monitored at each visit when tapering opioids?

Answer 17

• Pain status
• Withdrawal sx (ex: increased HR, sweaty, anxious, dizziness, lightheaded, nausea)
• Benefits of the taper (decreased pain, improved mood, energy level and alertness, decreased constipation)

Question 18

How often should tapering occur w/ opioids?

Answer 18

Frequently (q1-2weeks) w/ similar dispensing intervals

Question 19

How fast should you taper opioids?

Answer 19

• *Many tapering strategies; the point is to be cautious and follow the px response
• Decrease by ~10% of original dose q1-2weeks usually well-tolerated w/ minimal physiological adverse effects
• Once 1/3 of the original dose is reached, may slow taper to ½ or less of the previous rate (ex: if previously doing 10 mg q2weeks, then change to 5 mg q2weeks)
• Some px can be tapered more rapidly

Question 20

Canadian Opioid Prescribing Guideline – highlighted text

Answer 20

• May offer px a trial of opioids only after they have been optimized on non-opioid therapy, including non-drug measures
• Avoid opioid therapy for px w/ a history of substance use disorder (including alcohol) or current mental illness, and opioid therapy should be avoided in cases of active substance use disorder
• Restrict to < 90 mg MED (morphine equivalents daily) and suggest restricting the maximum prescribed dose to < 50 mg MED
• Px already receiving high-dose opioid therapy (90 mg MED or greater) should be encouraged to embark on a gradual dose taper to the lowest effective dose, potentially including d/c, rather than making no change in opioid therapy
• Discuss w/ px potential benefits, adverse effects, and complications to facilitate shared-care decision making
• Formal multidisciplinary program