PAIN RELIEF Flashcards
What are the steps of the WHO analgesic ladder?
Step 1 - Paracetamol +/- NSAIDs
Step 2 - Weak opioid such as codeine phosphate
Step 3 - strong opioid such as oramorph
How might you minimise the side effects of opioids?
Antiemetic PRN and laxatives regularly
How might you minimise the side effects of NSAIDs?
Gastric protection eg lansoprazole
How might you minimise the side effects of steroids?
Prescribe early in the day to reduce insomnia
Gastric protection eg lansoprazole
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What are the characteristic features of visceral pain?
Dull pain
Poorly localised
What is the best form of analgesia for visceral pain?
Usually opioid responsive
What are the characteristic features of bone pain?
Well localised
Worse on movement
Tender focally
What is the best form of analgesia for bone pain?
Partially opioid responsive
NSAIDs
Radiotherapy
Corticosteroids and IV pamidronate
Prophylactic fixation if risk of fracture
What are the characteristic features of neuropathic pain?
Burning
Stabbing
Shooting
May be associated with sensory / autonomic changes
What is the best form of analgesia for neuropathic pain?
Partially opioid responsive
Tricyclic antidepressants - amitriptyline 10-25mg OD titrated up to 100mg if tolerated
Anticonvulsants - gabapentin 300 mg OD titrated up to 300mg TDS if tolerated
What are the characteristic features of muscular pain?
Spasm
Tightness
Ache
What is the best form of analgesia for muscular pain?
NSAIDs
Muscle relaxant - diazepam 2-5mg BD-TDS or baclofen 5mg TDS
A patient presents to hospital in severe pain due to a pathological fracture of the femur which is subsequently found to be caused by metastatic breast cancer. Her pain is eventually controlled with 10mg of oramorph every 4 hours. How would you convert this to slow release oral morphine sulphate (MST Continus) so that she only had to take 2 tablets per day?
Calculate morphine dose over 24 hours:
10mg x 6 = 60 mg
Divide by 2:
60 mg / 2 = 30 mg
So she needs 30 mg MST Continus BD
A patient is on regular morphine sulphate for continuous analgesia. What should the dose of PRN breakthrough analgesia be?
1/6th of the total 24 hour dose of morphine sulphate
A patient is on 30 mg MST Continus (prolonged release morphine sulphate) BD. What should the dose of PRN breakthrough analgesia be?
This equates to 60 mg over 24 hours.
1/6th of 60 mg is 10 mg of oramorph
What is the conversion ratio between tramadol and oral morphine?
5:1
A patient’s pain is being well controlled on tramadol 100mg QDS however, it is decided that she should be switched to slow release morphine to minimise the number of tablets she is taking. What is the equivalent dose of slow release oral morphine sulphate (MST Continus)?
This equates to 400mg of tramadol over 24 hours.
The conversion ratio between tramadol and oral morphine is 5:1
So the equivalent dose of oral morphine is 80mg over 24 hours
So she should be on 40mg MST Continus BD
What is the conversion ratio between codeine phosphate and oral morphine?
10:1
So 60mg of codeine (standard dose) is equivalent to 6mg of oral morphine
What is the conversion ratio between oral oxycodone and oral morphine?
1:2
A patient’s pain was being controlled on 10mg of oral oxycodone QDS whilst abroad. However on returning home it is decided that this should be swapped to an equivalent dose of slow release oral morphine as oxycodone is significantly more expensive. What is the equivalent dose of MST Continus (slow release oral morphine)?
This equates to 40mg over 24 hours
The conversion ratio between oxycodone and oral morphine is 1:2
So the equivalent dose of oral morphine is 80mg over 24 hours
So they should be on 40mg MST Continus BD
What is the conversion ratio between IV or SC morphine sulphate and oral morphine?
1:2
What are the indications for using continuous subcutaneous infusion of morphine sulphate for pain control?
Difficulty swallowing or taking oral medications safely
Nausea and vomiting
Bowel obstruction
Too drowsy to swallow tablets or unconscious
Requires multiple SC injections
How often should the site of subcutaneous infusion of morphine sulphate be changed?
Every 3-4 days
What features would indicate that the site of subcutaneous infusion of morphine sulphate needed to be changed?
Red
Hot
Tender
Swollen
How many drugs may be put through a single continuous subcutaneous infusion, as long as there are no problems with interactions?
Up to 4
A patient’s pain is being controlled on 80mg of slow release oral morphine sulphate (MST Continus) BD, however, she is experiencing a lot of nausea and vomiting. It is decided that she should be started on continuous subcutaneous infusion instead. What is the dose of subcutaneous morphine sulphate that should be delivered over 24 hours?
Total dose of oral morphine sulphate over 24 hours is 160mg
Conversion ratio is 1:2
So equivalent dose is 80mg over 24 hours
What is the conversion ratio between IV or SC diamorphine and oral morphine?
1:3
What is the conversion ratio between IV or SC oxycodone and oral morphine?
1:4
What is the conversion ratio between IV or SC alfentanil and oral morphine?
1:30
What are the advantages of using a fentanyl patch rather than oral morphine for pain control?
Less constipation
How long will a fentanyl patch take to reach peak concentration in the body?
24-72 hours, so patient should be regularly topped up with PRN breakthrough analgesia
A patient’s pain is currently being well controlled with 30mg of oral slow release morphine sulphate (MST Continus) BD, however, she is experiencing a lot of constipation despite laxative use. It is therefore decided that she should be swapped to a fentanyl patch to control her pain. What dose of fentanyl patch (in mcg/hour) should she be started on?
36-70mg of oral morphine over 24 hours is equivalent to 12 micrograms/hour of fentanyl patch
A patient’s pain is currently being well controlled with 30mg of oral slow release morphine sulphate (MST Continus) BD, however, she is experiencing a lot of constipation despite laxative use. It is therefore decided that she should be swapped to a 12 micrograms/hour fentanyl patch to control her pain. How should the transfer be done?
The final tablet of MST Continus should be given at the same time as the initial patch application.
A patient’s pain is currently being well controlled with 40mg of oral slow release morphine sulphate (MST Continus) BD, however, she is experiencing a lot of constipation despite laxative use. It is therefore decided that she should be swapped to a fentanyl patch to control her pain. What dose of fentanyl patch (in mcg/hour) should she be started on?
75-90mg of oral morphine over 24 hours is equivalent to 25 micrograms/hour of fentanyl patch
A patient’s pain is currently being well controlled with 60mg of oral slow release morphine sulphate (MST Continus) BD, however, she is experiencing a lot of constipation despite laxative use. It is therefore decided that she should be swapped to a fentanyl patch to control her pain. What dose of fentanyl patch (in mcg/hour) should she be started on?
90-134mg of oral morphine over 24 hours is equivalent to 37 micrograms/hour of fentanyl patch
How often should a fentanyl patch be changed?
Every 72 hours
A patient is currently on 30mg of slow release oral morphine sulphate (MST Continus) BD. However, her pain is not being particularly well controlled and she is having to have breakthrough analgesia of 10mg of Oramorph roughly every 4 hours. What dose should her MST Continus be titrated up to?
Over 24 hours she is having 60mg of MST Continus plus 60mg of Oramorph, so 120mg.
She should therefore be started on 60mg of MST Continus BD.
What are the signs of mild opioid toxicity?
Vomiting
Increased drowsiness
Pinpoint pupils
What are the signs of moderate opioid toxicity?
Confusion
Muscle twitching/myoclonus
Vivid dreams/hallucinations
Agitation
What are the signs of severe opioid toxicity?
Respiratory depression (RR less than 8-10)
Hypotension
Loss of consciousness
How do we manage mild opioid toxicity?
Decrease opioid dose by 1/3rd
Ensure well hydrated
How do we manage moderate opioid toxicity in a patient on immediate release Oramorph?
Omit next dose
Re-start at a lower dose - decrease by 1/3rd
How do manage moderate opioid toxicity in a patient on slow release MST Continus (morphine sulphate)?
Temporarily convert to 4-hourly immediate release preparation on a decreased dose (by 1/3rd) and re-titrate
How do we manage moderate opioid toxicity in a patient on subcutaneous infusion of morphine sulphate?
Stop for 4-6 hours and review
If improving restart at lower dose - decrease by 1/3rd
How do we manage moderate opioid toxicity in a patient on a transdermal patch of fentanyl?
Seek specialist advice from palliative care team
How do we manage severe opioid toxicity?
Stop opioid
Consider naloxone 400 micrograms to 2mg IV
Repeat every 2-3 mins until respiratory function improves
Beware that naloxone effect wears of quickly so will need close monitoring
