Pain management Flashcards
What analgesics to prescribe a palliative patient when starting treatment?
names, doses + adjuvants
- oral modified-release (MR) or oral immediate-release morphine
- oral immediate-release morphine for breakthrough pain
- use 20-30mg of MR a day with 5mg morphine for breakthrough pain
- laxatives should be prescribed
- patients should be advised that nausea is often transient. If it persists then an antiemetic should be offered
- drowsiness is usually transient - if it does not settle then adjustment of the dose should be considered
What’s the dose of breakthrough morphine?
the breakthrough dose of morphine is one-sixth the daily dose of morphine
What are the preferred opioid options for a patient with renal failure
- oxycodone → if renal failure is not severe
- fentanyl/ alfentanil or buprenorphine → in severe renal failure
How can metastatic bone pain be managed?
- strong opioids
- bisphosphonates
- radiotherapy
- denosumab (monoclonal antibody RANKL inhibitor)
* NSAIDs are not particularly effective for metastatic bone pain
How much should we increase to dose by when increasing the opioids?
When increasing the dose of opioids the next dose should be increased by 30-50%.
Convert oral codeine to oral morphine
oral codeine → oral morphine
Divide by 10
Convert oral tramadol to oral morphine
oral tramadol → oral morphine
Divide by 10
What are the advantages of use of oxycodone instead of morphine?
Oxycodone generally causes:
- may be used in renal failure (unless severe)
- less sedation, vomiting and pruritis than morphine
*but oxycodone causes more constipation
Convert oral morphine to oral oxycodone
oral morphine → oral oxycodone
Divide by 1.5 - 2
How much of transdermal fentanyl equals oral morphine?
transdermal fentanyl 12 microgram patch equates to approximately 30 mg oral morphine daily
How much of transdermal buprenorphine equals oral morphine?
transdermal buprenorphine 10 microgram patch equates to approximately 24 mg oral morphine daily
Convert oral morphine to SC morphine
oral morphine to SC morphine
divide by 2
in which units do we have alfentanil doses?
micrograms
Examples of ‘adjuncts’ to analgesics (classes)
Adjuvants → drugs that are not technically analgesics but may relieve pain resistant to conventional analgesics
- anti-depressants e.g. neuropathic pain (as acting on descending tract)
- anti - spasmodic (smooth muscle relaxants)
- selective anti-inflammatory drugs e.g. Coxibs
- corticosteroids
- anti-convulsants
- skeletal muscle relaxants
- bisphosphonates
- NMDA-receptor blockers
Examples, MoA and advantage of selective anti-inflammatory drugs
‘Coxibs’
MoA: inhibit COX2
Examples: Celacoxib, Etoicoxib
What’s used for muscle spasms? (2)
benzodiazepines, baclofen
What are (2) 4th line drugs for neuropathic pain?
Ketamine and Methadone
- both work on NMDA receptors (block them)
- only specialist use
Meaning of 123ABC
123 - WHO analgesic ladder
ABC - adjuncts, bowel, co-fctors
WHO analgesic ladder
1. Non-opioid (e.g. NSAIDs, paracetamol)
2. Weak opioids (e.g. codeine, tramadol, dihydrocodeine) + paracetamol
3. Strong opioids (e.g. morphine, fentanyl, buprenorphine) + paracetamol
What’s meant by A (in 123 ABC)?
Adjuvants: e.g. anti-inflammatory, steroids, anti-epileptics, anti-depressants ⇒ to further manage pain
What’s meant by B in 123 ABC?
B - bowels
- prevent constipation
- gastric protection PPI (if needed)
- anti-emetics for sickness
What’s meant by C in 123 ABC?
C - co-factors
- non- pharmacological management
- holistic approach
All extras for pain management ‘CHAIRS’
C - chemotherapy
H - hormones
A - regional analgesia
I - immunotherapy
R - radiotherapy
S - surgery
Types of opioid receptors?
- mu
- delta
- kappa
- ORL-1 (opioid like receptor_)
work by:
opioid + receptor → G protein activated → effect via 2nd messager
Why do we use heavily opioid analgesics in palliative care but not in any other speciality?
Opioids are harmful ling term - e.g. cause infertility
In palliative care we do not worry about long term side effects as more important is symptomatic control
Side effects of opioid toxicity (!)
This is important, carer’s need to be advised about them
- sedation and confusion
- nausea and vomiting
- constipation
- pin-point pupils
- respiratory depression
- myoclonus (jerky muscles)
- rashes (due to histamine release)
What drug (analgesic) can we use in liver failure?
Morphine
(but not in renal failure!)
What’s the dose of breakthrough pain analgesic?
1/6 of total dose in 24 hours
Examples of ‘non-drug’ methods od pain relief
- massage
- TENS
- heat/cold
- walking aids/wheelchairs
- immobilisation (splints/slings/corsets)
- hoists
- mattresses
- dressings
What’s max dose of paracetamol in 24 hours?
4 g
Max codeine dose in 24 hours
max 240 mg in 24 hours
Max dihydrocodeine dose in 24 hours
240 mg / 24h
Max dose of Tramadol
400 mg / 24 hours
Convert PO morphine into SC diamorphine
Divide by 3
Convert PO morphine to SC morphine
Divide by 2
What type of pain anti-depressants/anti-convulsants may be useful for?
Neuropathic pain
Can we use Fentanyl patches in an opioid-naive person?
No
(the potency is too much)
How to prescribe morphine? by weight or volume?
By weight e.g. 10 mg (NOT 10 ml)
A typical starting dose of morphine regimen
1. Immediate release liquid or tablet morphine sulphate 5-10 mg every 4 hours
PLUS
2. Same dose up to hourly PRN for breakthrough pain
PLUS
3. Stimulant and softening laxative e.g. movicol +/- senna
What dose of opioid do we start in a very frail or opioid-naive patient?
2.5 mg or less
(usually 5 - 10 mg)
If we start opioid (starting dose) and the pain is uncontrolled (but responding to opioid) what do we do?
Increase regular 4 hourly doses by 30-50%
PLUS
Same dose for breakthrough pain hourly PRN
If pain is controlled by starting dose/trial of opioid, what to do?
Give total daily dose oral morphine in two divided doses as 12 hr slow release morphine (MST)
(so twice daily every 12 hours)
PLUS
1/12 or 1/6 total daily dose oral morphine as breakthrough pain hourly PRN
Management options for N/V associated with opioid analgesia
Reassure of temporary nature
Pharmacological options:
- metoclopramide 10 mg TDS for few days
- Haloperidol 1.5 mg at 7 pm for few days
- Cyclizine 50 mg TDS for few days
When to change opioids? (pt’s symptoms)
- persistent N/V despite regular anti-emetics
- mental clouding/confusion
- hallucinations unresponsive to halloperidol
- persistent unresponsive postural hypotension
- pruritis resistant to anti-histamines
- myoclonus
- deteriorating renal function
How do we prescribe morphine/oxycodone/ fentanyl and why? (brand or generic name)
Brand name
- there are different modified release mechanisms
How long does it take for immediate-release morphine to have an effect?
20-30 minutes
Name for Oxycodone:
A. slow release 12-hour tablet
B. Immediate release capsule/ liquid
Oxycodone
A. Slow release 12 hour tablet → Oxycontin
B. Immediate release capsule/ liquid → Oxynorm
How much more potent than PO morphine is PO oxycodone?
PO oxycodone twice as potent as PO morphine
How much potent is injectible oxycodone than PO oxycodone?
Injectible oxycodone (oxynorm) is twice as potent as PO oxycodone (oxycontin)
How long is one fentanyl patch used for?
72 hours
- the effects continue to act up to 24 hours after removal of patch
- peak plasma concentration is not reached until 12-24 hours after first patch is applied
Alfentanil
- route
- use in renal failure
- how it can be given (2)
- pothency
Alfentanil
- SC route
- it’s short-acting
- can be used in renal failure
- can be given PRN (hourly) or via CSCI
- 10 times more potent than injectable diamorphine
Buprenorphine
- route
- when to evaluate its effects
- use in renal and hepatic impairment
Buprenorphine
- patch
- should not evaluate effects for at least 72 hours after application (allow plasma concentration to increase)
- well - tolerated in renal and hepatic failure
