cancer pain

Complications

• increasing back pain in a patient with known spinal metastases should cause concern for spinal cord compression (see Management:)

• disease interaction(s) of cancer pain with chronic renal failure

Management

• use acetaminophen, aspirin or NSAIDs for mild to moderate pain
  • may be continued after addition of opioid
• if pain persists of increases, add a low-dose or low-potency opioid
  • reasonable to go straight to strong opiate (morphine, oxycodone) if non-opioid analgesics insufficient
  • no specific opioids recommended over others
• increase opioid potency or use higher doses for persistent pain or moderate to severe pain at onset
  • initiate opioid at lowest possible dose
  • no specific dosage escalation, but increases of 25-50% common
• add adjuvant agents at any step
  • neuropathic pain
    • tricylcic antidepressants
    • anticonvulsants
    • local anesthetics
• topical analgesics
  • corticosteroids
  • anti-inflammatory
  • mood elevation
  • appetite stimulation
  • osteolytic bone lesions
    • IV bisphosphonate (pamidronate zoledronate)
    • pregabalin ineffective for painful bone metastases
• prescribe analgesics around the clock for persistent, chronic pain, rather than as needed
• do not exceed maximum doses of NSAIDs & acetaminophen
  • be judicious in accounting for analgesic combinations
  • acetaminophen: 4000 mg/day
  • ibuprofen 2400 mg/day, naproxen 1250 mg/day
  • aspirin 4000 mg/day
• treatment of acute cancer pain with bolus doses of intravenous opioids
  • do not use partial opioid agonists (buprenorphine)
  • do not use meperidine (even with biliary disease)
    • naloxone does not reverse CNS toxicity caused by normeperidine & may actually increase neuroexcitability
• IV patient-controlled analgesia (morphine pump) in hospitalized patients
  • hydromorphone is a better option in patients with impaired renal function
  • basal rate equivalent to 50-100% of 24 hour outpatient dose
  • demand dose of 10-20% of 24 hour outpatient dose
• manage chronic pain with around-the-clock long-acting opiates plus short-acting opioids for breakthrough pain
  • start long-acting opiate with 30-50% of 24-hour opioid dosage
  • dose breakthrough opioids at 10-15% of the morphine equivalent daily dose every 3-4 hours
• titrate total analgesic dose by adding the total opiate dose (long-acting + short-acting) & using this dose for the new around-the-clock long-acting opiate dose
  • titration easiest if both long-acting & long-acting opiate are the same drug
• recognized & manage adverse effects of opiates
  • constipation:
    • prophylaxis with initiation of opiates
    • stool softener
    • stimulant laxative
  • sedation
  • delirium (rotate to different opiate)
  • nausea
  • pruritus: antihistamines
  • except for constipation, tolerance develops
• tolerance & physical-dependence is not addiction
• interventional strategies for refractory pain
  • intrathecal opiates
    • small doses can have profound analgesic effects & cause fewer adverse effects than would systemic opioids
    • start with temporary intrathecal drug delivery system
  • palliative sedation to relieve intractable pain in terminally ill patients
  • rotate opioid to another opioid if pain persists despite high-dose of one opioid (i.e. morphine to methadone)
• interventions for specific cancer pain presentations
  • unremitting neck pain or back pain
    • spinal imaging (MRI of spine to rule out spinal cord compression)
    • intravenous glucocorticoids (dexamethasone)
    • admit & initiate intravenous morphine (bolus dosing)
  • celiac plexus block vs celiac plexus neurolysis for intractable pancreatic cancer or other upper abdominal cancer pain
  • cachectic patients do not absorb fentanyl well
• massage therapy is helpful
  • 20 minutes 3-4 time/week provided by a caregiver can alleviate cancer pain & improve mood
• acupuncture may be of benefit
• both acupuncture & massage associated with pain reduction & improved fatigue, insomnia, & quality of life
  • no significant different between acupuncture & massage therapy
• screening for risk of substance abuse suggested
  • use CAGE questions modified for opioid use

* opiate dose is only limited by signs of overdose

More general terms

• cancer complication
• pain [odyn-]