Palliative Care: Pain Flashcards
What is pain?
It involves the perception of a painful stimulus by the nervous system and a reaction of a person to this
What percentage of those with advanced cancer have pain?
75-90%
Pain can be controlled in 80% using what approach?
Stepwise approach
Describe pain in advanced disease
Usually persistent Can have multiple aetiologies Impairs function Threatens independence Invokes fear of further suffering and death
What can cause the pain?
The cancer itself
Anti cancer treatment
Cancer related debility e.g mucositis, neuropathy
Concurrent disorder e.g OA
What factors can exacerbate pain?
Anger Anxiety Boredom Depression Discomfort Grieving Insomnia / fatigue Lack of understanding Social isolation
What factors can reduce pain?
Acceptance Mood elevation Creativity Relief of other symptoms Space to talk, empathy Sleep Explanation Compassion
How can pain be assessed during history taking?
Site Quality Intensity Timing - onset, duration, progression, previous Aggravating factors Relieving Secondary symptoms
What is nociceptive pain?
Normal nervous system
Identifiable lesion causing tissue damage
- somatic or visceral
What is somatic pain?
Pain originates from skin, muscle, bone
What is visceral pain?
Pain originates from hollow viscus or solid organ
What is neuropathic pain?
Malfunctioning nervous system
Nerve structure is damaged
What words are often used to describe somatic and visceral pain?
Somatic - sharp, throbbing, well localised
Visceral - diffuse ache, difficult to localise
How is neuropathic pain often described?
Stabbing Shooting Burning Stinging Numbness Hypersensitivity
What does a pain assessment need to include?
Impact on all areas of life - physical, social, psychological
Their understanding of the pain
Any concerns about treatment of the pain
Describe the WHO analgesic ladder
Level 1: non opioid +/- adjuvant
Level 2: opioid for mild to moderate pain +/- non opioid +/- adjuvant
Level 3: opioid for moderate to severe pain +/- non opioid +/- adjuvant
What examples are there for non opioid pain?
Paracetamol
NSAIDS
Aspirin
What are adjuvants for pain relief?
Drugs whose primary indication not for pain
Consider if pain only partially responsive to opioid analgaesia
Can have opioid sparing effect
What adjuvant pain relief examples are there?
Antidepressants- duloxetine, amitriptyline Anticonvulsants- gabapentin, pregabalin Benzodiazepines- diazepam Steroids - dexamethasone Bisphosphonates- for bony pain
What medication is good for neuropathic pain?
Amitriptyline 10-25mg nocte
Gabapentin 300mg TDS over 3/7
Pregabalin 75mg BD
What opioids are typically used in step 2 for mild to moderate pain?
Dihydrocodeine
Codeine phosphate
Tramadol
Co-codamol (combination of codeine and paracetamol)
What opioids are typically used for step 3 for moderate to severe pain?
Oxycodone
Morphine
Fentanyl
Diamorphine
Soft tissue pain has what type of response to opioids?
Good response
Does bone pain respond well to opioids?
Partial response
Responds well to NSAIDS and radiotherapy
Bisphosphonates
Does neuropathic pain respond well to opioids?
Often poor
What are the most common side effects of opioids when used for persistent pain?
Constipation
Dry mouth
Nausea and vomiting
Drowsiness and sedation
Other side effects: pruritis, rash, urinary retention, respiratory depression, confusion, hypogonadism
What are some potential anxieties when commencing morphine?
Addiction Tolerance/ loss of effectiveness The end of the road Last resort Severe side effects
What should you write up alongside opioid?
Anti emetic
Laxative
What are some principles that you should not do with regards to opioid prescribing?
Don’t start too high a dose
Don’t titrate up too quickly
Don’t make patients wait 4 hours for a PRN dose
What are signs and symptoms of opioid toxicity?
Pinpoint pupils Hallucinations Drowsiness Vomiting Confusion Myoclonic jerks Respiratory depression
What can improve liver pain?
Steroids/ NSAIDS
What 3 strengths does codeine come in?
15mg
30mg
60mg
Codeine is a prodrug of morphine. What does this mean?
It is metabolised into an active agent (morphine)
Why is codeine ineffective in some people?
Some people have deficiency of the CYP2D6 enzyme, which means they are poor metabolisers of codeine into morphine
What is the ratio of codeine:morphine ?
10:1
240mg codeine = 24mg morphine
What is the recommended total daily dose of morphine?
24mg (20-30mg)
So generally prescribe:
Morphine SR 15mg BD
Morphine IR 5mg PRN (for breakthrough pain)
What are the options for oral morphine immediate release?
Oramorph liquid 10mg/5ml, 100mg/5ml
Sevredol tablets 10,20,50mg (not common)
What options are there for slow release oral morphine?
Zomorph capsule BD (10,30,60,100,200mg)
MST tablets BD (5,15,30,60,100,200mg)
Should all patients on regular SR opioids have IR opioid for break through?
Yes
How is further titration of opioid dose calculated?
Add up their TTD ie 24 hours worth of morphine
TTD/2 = new morphine SR dose (BD) TDD/6 = new morphine IR breakthrough PRN dose
Same principle for calculating new syringe driver dose (TDD = new dose in syringe driver, PRN subcutaneous = TDD/6)
The breakthrough dose of morphine is what fraction of the daily dose?
1/6
Subcutaneous morphine is …..the strength of oral morphine
Double
What does successful pain control involve?
Regular and PRN doses
Titration of dose against effect with no rigid upper limit for strong opioids
Appropriate time interval between doses
Sufficient dose to prevent return of pain before next dose due
Willingness to give strong opioids early when other analgesics fail
Early consideration of adjuvants
Is regular review and assessment important?
Yes
What is the conversion factor of oral morphine to oral oxycodone?
Divide by 1.5 to 2
A transdermal fentanyl 12 micro gram patch equates to approximately how much morphine?
30mg oral morphine daily
A transdermal buprenorphine 10 microgram patch equates to how much morphine?
Approximately 24mg oral morphine daily
Opioids should be used with caution in people with what?
Chronic kidney disease
buprenorphine and fentanyl are preferred - not excreted renally
Compare the side effects of oxycodone and morphine
Oxycodone generally causes less sedation, vomiting and pruritis than morphine but more constipation
How do NSAIDS work?
Inhibit prostaglandin synthesis via inhibition of COX-1 and COX-2 (and therefore reduce inflammatory response)
They also inhibit platelet aggregation (especially aspirin)
How does aspirin work?
Irreversibly inhibits COX1 - preventing thromboxane A2 synthesis.
(Thromboxane causes platelet aggregation)
COX2 selective inhibitors have less gastrointestinal side effects, but increase the risk of…
Heart attack - they promote thrombosis
What are the side effects of NSAIDS?
I- GRAB
Interactions with other drugs e.g warfarin (increased bleeding risk)
Gastric ulceration - consider PPI
Renal impairment - vasoconstriction of afferent arteriole
Asthma sensitivity - can cause bronchospasm
Bleeding risk
And cardiovascular risk:
- increased risk of MI, stroke, HF (apart from aspirin)
Why do NSAIDS cause GI side effects and what are they?
1) the molecule directly irritates the mucosa
2) inhibition of prostaglandin synthesis causes increased gastric acid secretion and diminished bicarbonate and mucus secretion
Side effects: N&V, indigestion, gastric ulceration or bleeding, diarrhoea
Why can NSAIDS cause chronic kidney disease?
Prostaglandins usually dilate the afferent arterioles of the glomeruli to help maintain normal glomerular filtration rate, so NSAIDS cause constriction and consequently reduced kidney perfusion.
Are the main therapeutic effects of NSAIDS via COX1 or COX2?
COX2
COX2 selective inhibitors have less GI side effects but substantially increase risk of..
Heart attacks, so generally contraindicated due to high rate of undiagnosed vascular disease
Opioids activate what receptors?
Opioid receptors:
Mu
Delta
Kappa
What drug should be given if opioid overdose?
Naloxone - an opioid antagonist, reverses respiratory depression
Diamorphine is more lipid soluble than morphine. What implications does this have?
Passes through BBB quicker
Half life = 5 minutes, quickly converted to morphine
A way to get a big dose of morphine into brain/ body rapidly
When prescribing controlled drugs, what rules need to be followed?
Name and ID of patient
Write prescription as normal
Write supply and give pharmacist exact instructions:
Drug NAME, FORM, STRENGTH
Example TTO:
Take morphine SR (Zomorph) 60mg BD for 14 days
Supply: 28 (twenty eight) morphine SR (zomorph) 60mg capsules
When writing a TTO for controlled drugs, how much supply do you normally give?
2 week supply
When writing a TTO for PRN breakthrough pain relief, how many doses a day should you generally allow for?
2 doses per day
What is first line treatment in palliative care patients when oral treatment not suitable?
Transdermal opioid patch formulations e.g fentanyl patch 12 mcg/ hr
Nausea due to starting opioid is typically transient. True or false?
True, but if persistent offer anti emetics
How are fentanyl and buprenorphine metabolised?
Hepatic metabolism, so useful to use if patient has renal impairment
Who are transdermal patches suitable for?
Those with stable levels of pain who will not require regular titration of pain relief.
Not for opioid naive patients
What is the conversion of oral morphine to transdermal fentanyl?
1:100
What is the conversion of oral morphine to oral codeine?
1:10
What is the conversion of oral morphine to oral tramadol?
1:10
Does morphine hasten death?
No
It is used in end of life care for pain and distressing dyspnoea
