Pain

There are 12 essentials to know when prescribing opioids:

1. Opioids are the medication of choice for both pain and dyspnea in advanced disease.
2. Patients with addiction should have pain/dyspnea treated — use buprenorphine, adjuvant medications, limited breakthroughs, small amount dispensed frequently.
3. Opioids are safe in cardiopulmonary disease, but start low go slow.
4. Persistent symptoms require regular dosing, i.e. short-acting opioid q4 hours.
5. Not all opioids are the same, and inter-individual analgesia/side effects vary widely.
6. Opioids with few or no active metabolites are preferred for those with renal failure or frailty.
7. Always order breakthrough with regular dosing: 10% of total daily opioid dose q1h prn. Recalculate breakthrough dose when regular dose is changed.
8. If 3 or more breakthroughs used in the last 24 hours, increase the regular dose.
9. Titrate dose to the best symptom control with the fewest side effects.
10. When you prescribe an opioid, prescribe a laxative.
11. If side effects are intolerable, consider rotating opioid.
12. Educate patient/family about control of symptoms and opioid safety.

Name	PO dose
Tylenol #3 (codeine 30mg/acetaminophen 325mg)	2 tablets
Morphine	10mg
Hydromorphone	2mg
Oxycodone	7.5mg
Fentanyl – see note below Buprenorphine – see note below

Morphine to fentanyl

Fentanyl 25mcg/hr patch = 60-134mg morphine/day orally.

No active metabolites – good choice in frail elders and patients with renal failure – BUT – use upper conversion range.

Patients with normal renal function and non-elders use lower conversion range.

Lowest dose patch=12mcg/hr, but can remove half of backing and dose is 6mcg/hr

Breakthrough dose
Calculate breakthrough dose based on morphine equivalents of the patch.

Morphine to buprenorphine

buprenorphine provides pain relief while lowering risk of respiratory depression and misuse, compared to other opioids.

analgesic of choice for pain/dyspnea and risk/history of opioid use disorder (OUD)

prolongation of QTc but no torsade des pointes, safe with antidepresssants

highly lipophilic – like fentanyl and methadone

excretion of buprenorphine primarily through gut – good for patients with renal failure

buprenorphine 1:1 fentanyl when used parenterally, use same conversion ratio as morphine to fentanyl

buprenorphine transdermal patch excellent choice in frail elders +/- renal failure: can be started in opioid naive due to slow onset, excretion through gut, transdermal avoids oral and gut issues

transdermal patch comes in 5, 10, 20 mcg/hr patches, when rotating to transdermal buprenorphine in frail elders use upper conversion (same as fentanyl)

buprenorphine doesn’t block all opioid receptors until dose at least 60mcg/hr so use other opioid as breakthrough dose

Opioid	Starting p.o. dose	Oral/ SC dose	Starting p.o dose frail, older/CRF	Active metabolites
Tylenol 3	avoid	2 tabs/ n/a	avoid	+++
Morphine	5-10 mg q4h	10mg/5mg	2.5-5mg q4hr	+++
Hydromorphone	1-2mg q4h	2mg/1mg	.5-1mg q4h	++
Oxycodone	5-10mg q4h	7.5mg/ n/a	2.5-5mg q4h	0
Methadone (consult palliative care if new user)	2-5mg q8h	1mg/0.5mg	1mg q12h	0

Footnotes
Starting po dose based on patient being opioid naive: patient has NOT had 5 days of continuous opioid exposure (i.e. short-acting q4hr po/sc; long-acting q12hr; transdermal)
Morphine conversion factor: see Opioid Equianalgesic Table

Methadone: Variable half life and dosing. Consult palliative care if not familiar with this medication.

Corticosteroids

• metastatic bone and visceral pain
• raised ICP
• neuropathic pain where nerve compression occurring
• dexamethasone 8-16mg po/sc daily in am, if effective at 48 hours reduce to lowest effective dose

Ketamine Consult PC

• 3rd line after opioids and other adjuvants for neuropathic pain, incident pain,
• IV product may be given p.o./s.c./IV. highly lipophilic. NMDA antagonist
• Optimal dosing unclear. Start 1-3mg/hr s.c. infusion and titrate to dose of 50-500mg/24 hr. Continue for several days then reassess
• Oral route results in the active metabolite norketamine, oral route more potent compared to the subcutaneous, intranasal, sublingual, IV.

Neuropathic pain
(includes pain secondary to ischemia)

• corticosteroids
• antidepressants: venlafaxine, mirtazapine, duloxetine, nortriptyline
• anticonvulsants: gabapentin, pregabalin
• consider nerve or plexus blocks, neurosurgical procedures

Metastatic bone pain

• radiotherapy
• corticosteroids
• bisphosphonates useful in widespread disease: pamidronate IV 90mg in 250ml of D5W over 2 hrs q 4 weeks. Avoid if severe renal failure
• NSAIDS: naproxen
• Consider vertebroplasty, cementoplasty, surgical splinting

Visceral pain

• corticosteroids
• colicky pain: hyoscine butylbromide 10-20mg p.o./s.c. tid-qid,
• celiac plexus block

topical opioids in wound pain. Opioid receptors in tissue at base of wound. If wound only source of pain, can use topical rather than systemic opioid. See Manage section Wound Care

• subtype of breakthrough pain with a predictable trigger i.e. movement, procedural (wound dressing change), body function (e.g. bowel movement with rectal tumor) Pain typically high intensity and short lasting.
• Sufentanil 6.25mcg-50mcg sublingual/subcutaneous for use in patients on regular opioids
• Fentanyl 12.5mcg-50mcg sublingual/subcutaneous for frail older adults
• Onset: 10min Offset: 30-60min Must be held sublingual for >1min. Not absorbed if swallowed
• Midazolam 0.5-2mg subcutaneous if anxiety and pain
• Ketamine single sublingual or subcutaneous dose. Consult PC

• Consider total pain when extensive investigation does not find source of pain, multiple medications trials not effective, pain resolving but distress still high, request for hastened death
• Multi-professional assessment needed, involve palliative care team
• Psycho-Existential Symptom Assessment Scale    https://www.endoflifeessentials.com.au/Portals/14/document/Psycho-existential-assessment-V2_SAS-Form-Jan2020_Colour.pdf
• See Manage section Existential distress