Pain Palliation Flashcards
Somatic Nociceptive Pain
- Dull
- Aching
- Well-localized
- Skin, bone, joint, soft tissues
EX:
-Mets to bone or fractures
Visceral Nociceptive Pain
- Diffuse
- Deep
- Aching
- Gnawing
- Poorly localized
EX:
- Bladder distension/cramping
- Intestinal distention
- Constipation
- Angina
Neuropathic Pain
- Burning
- Shooting
- Pricking
- Parasthesias
EX:
- Phantom limb pain
- SCI Pain
- Stroke
- Diabetic Neuropathy
- Post-herpetic neuralgia
Pain + Cancer
- One of the most common and feared symptoms
- Negative impact on several life factors and overall QoL
Acute Pain + Cancer
- Diagnose via biopsy or lumbar puncture
- Intervene with stent placement paracentesis, or chest tube insertion
Chronic Pain + Cancer
- Tumor-related
- Somatic, visceral, or neuropathic
Durations of Pains
- Acute: seconds to less than 3 months
- Peripheral nociceptors activated and COX enzymes/prostaglandins are released
- Chronic: >= 3 mo
- Sensitization at the level of spinal neurons via multiple mechanisms
- Breakthrough: Seconds to hours
- Due to movement, spontaneous, or from weaning off drugs or effect of drug in a well-treated patient
Chemo-Related Pains
- Oral mucositis**
- Neuropathy**
- Arthralgia/myalgia
- Hand-foot syndrome
- Chemo-induced headaches
Opioid Indications
- Treating moderate to severe pain that doesn’t respond to non-opioids alone
- Used for acute and breakthrough pain, cancer pain, visceral/somatic pain, opioid sparing regimens, and treating addiction
- Possible AE: Cough, diarrhea, dyspnea, opioid dependence
Opioid MoA
- Bind to receptors in CNS
- Inhibits transmission of nociceptive input from periphery to spinal cord
- Alters limbic system activity
- Modifies sensory and affective aspects of pain
Opioids + Renal Failures
Caution with:
- Meperidine
- Morphine
- Codeine
- Tramadol
Opioids + Liver Failure
- Codeine
- Meperidine
- Methadone
Opioid Escalation Strategies
- For moderate to severe pain increase opioid TDD by 50-100% regardless of starting dose
- For mild to moderate pain, increase by 25-50% of TDD regardless of starting dose
- Increase short-acting opioids safely every 2 hours
- Long acting opioids can be safely increased every 24 hours (excluding methadone and patches)
Fentanyl Patches
- Good for chronic, stable pain
- DON’T give to opioid naive patients
- NOT good for rapid escalations
- > 12 hour onset of action and 3 days to steady state
- Unusual conversion to MME
Transmucosal Fentanyl
- Required REMS training for providers
- Buccal tabs, film, oral lozenge, nasal or SL spray, SL tablet
- Starting dose: 100 mcg with duration of axn 1-2 hours (opioid TOLERANT)
- Only use in failed standard IR therapies
Methadone
- Treat opioid dependent patients
- Long duration of action, efficacious, cheap
- Good for chronic pain
- Comparative efficacy to morphine for cancer pain
- Mu agonist and NMDA antagonist
- May help overcome tolerance and toxicities
- Extensively metabolized hepatically (avoid in liver failure)
Cardiac Concerns + Opioids
- Caution in combination with other QT prolonging agents
- EX: antipsychotics, antidepressants, antibiotics, antiemetics
- Low potassium/magnesium can increase risk
Good Methadone Patients
- True morphine allergies
- Significant renal impairment
- Neuropathic pain
- High pill burdens
- Difficulty swallowing or PEG tube
- Benefit from long-acting opioids
Bad Methadone Candidates
- Many DDI in regimen with methadone
- History of syncope or arrhythmias
- Live alone
Cannabis + Cancer Pain
- Elevated levels of CB1 found in brain areas that modulate nociceptive processing
- Agonists of CB1 and 2 have peripheral analgesic axns and possibly anti-inflammatory
- Doesn’t work at same sites at opioids
- Opioid-sparing effects
- Used in peripheral neuropathy
- Also helps with anxiety, sleep, and N/V in cancer patients
Reasons to Change Opioids
- Lack of response
- AE
- Change in patient status
- Drug/Formulation availability
- Formulary issues
- Health care beliefs
Hyperalgesia
- Paradoxical reaction where patient becomes more sensitive to certain stimuli and could experience pain from normal stimuli
- Accompanied by neuroexcitatory signs/symptoms (confusion, hallucinations, myoclonus)
- Usually high dose opioids >1000 mg OME
- Treat by reducing dose, rotating opioid to synthetics, supportive measures
Incomplete Cross-Tolerance
- Profound response in untolerated receptors when switching opioids
- Decreased new opioid dose by 25-50% of patients current MME
Chronic Opioid AE
- Constipation
- No tolerance develops
- Treat with stimulant (senna +/- osmotic agent)
Acute Opioid AE
- N/V
- Sedation
- Confusion/hallucinations
- Pruritis/itching
- Lasts a week or less
- Treat by lowering doses, changing agents, or adding other supportive drugs (antihistamines, steroids, antipsychotics, dopamine antagonists, Zofran)
Neuropathic Pain Options
- TCAs: amitriptyline, nortriptyline, desipramine (effective at 50-150 mg)
- SNRIs: duloxetine (<60 mg BID), venlafaxine
- Topicals?
- Calcium Channel Alpha-2 ligands: Gabapentin, pregabalin (inhibits calcium influx and diminishes neuronal hyperactivity)
Ketamine
- Anesthetic with analgesic, dissociative, sedative, and amnestic properties
- Subanesthetic dosing to treat intractable pain (severe neuropathic pain not responding to opioids)
- May reduce opioid tolerance
- Antagonizes NMDA receptors on dorsal horn of spinal cord
Bone Metastases Care
- Corticosteroids
- NSAIDs
- Calcitonin
- Bisphosphonates
- Denosumab
- External beam radiation therapy
- Radiopharmaceuticals
Patient Perspective + Opioids
- Identify fears/concerns about opioid use and cancer pain
- Address potential self management
- Educate about appropriate use and SE
- Maintain good provider/patient communication