Pain Management Flashcards
Score 0 on acute pain analgesia scoring
No pain at rest
No pain on movement
Score 1 on acute pain analgesia scoring
No pain at rest
Slight pain on movement
Score 2 on acute pain analgesia scoring
Intermittent pain at rest
Moderate pain on movement
Score 3 on acute pain analgesia scoring
Continuous pain at rest
Severe pain on movement
Step 1 of WHO analgesic ladder:
scoring and drugs
Score 0-1
Paracetamol 1g 6-hourly PO/PR/IV
max 60mg/kg daily
Step 2 of WHO analgesic ladder:
scoring and drugs
Score 1-2
Paracetamol 1g 4-6 hourly
PLUS
Codeine 30-60mg 4-hourly (max 240mg/24h)
OR
Tramadol 50-100mg 4-hourly (max 600mg/24h)
+/- NSAIDs: ibuprofen 400mg 8 hourly MAX 48h then review
Step 3 of WHO analgesic ladder:
scoring and drugs
CONTINUE
Paracetamol
NSAIDs
Replace Tramadol or Codeine with: Oramorph OR PCA Morphine OR Short duration IV/IM/SC morphine OR Regional technique e.g. epidural
Breakthrough analgesia:
What drug is recommended?
How is dosing calculated?
Oxynorm 5mg or Oramorph 10mg
Breakthrough analgesia should be 1/6th of total daily dose
If patient’s pain is still not controlled with Morphine what can be given
Oxycodone Sustained Release (Oxycontin)
Usual dose of Orapmorph
10mg/5mls
How can IV morphine be used as ‘rescue analgesia’
given as 2mg boluses every 5 mins up to 10mg
in elderly or frail - 1mg boluses
Where should IV morphine be written on the Kardex
PRN or Once Only section
Compare the potency of Tramadol and Morphine
Tramadol is less potent than morphine
Why is IV Tramadol not used as rescue analgesia
Fast administration is very unpleasant for patients and can induce seizure
Which route is preferred for morphine: IV/SC/IM
IV if possible - but IM/SC has a place for short term acute pain
Patients on continuous morphine infusion - where should they be cared for
HDU or ICU with level 1 care
What patients are suitable for continuous morphine infusion
patients on long term opioid therapy who are unable to take their regular strong opioids
standard UK dose of PCA morphine
1mg morphine bolus, with 5 min lockout
Combining opioids whilst on PCA morphine - advised/not advised?
NOT ADVISED - must not be on any other opioid analgesics - but will benefit from NSAIDs and paracetamol
If patient is receiving IV morphine, how is the dose of oral morphine calculated for step down?
Oral:IV = 2:1
Oral is double the dose of IV
Drugs commonly used in spinal opioids
fentanyl (lasts up to 4 hours)
diamorphine (lasts up to 12 hours)
morphine (lasts up to 24 hours)
Naloxone
opioid antagonist
the 3 indications for administration of Iv naloxone
sedation score = 3
patient has shallow resps or RR < 8/minute
patient has pinpoint pupils
Compare the half life of naloxone to the half life of opioids
Naloxone is SHORTER than opioids.
Naloxone may have to be repeated after 20-30 minutes
Side effects of morphine
Nausea and vomiting (can give anti-emetics)
Constipation (Senna)
Itch (often given with antihistamines)
Assessment and scoring system for N+V
0 = none 1 = mild (nausea only) 2 = moderate (vomited once) 3 = severe (vomited more than once)
4 groups of anti-emetic drugs
5HT3 antagonists
Antihistamines
Antidopaminergics
Anticholinergics
5HT3 antagonists
anti-emetic
Ondansetron, Granisetron
Antihistamine used for anti-emetic
Cyclizine
Antidopaminergic used as anti-emetic
Prochlorperazine
Metoclopramide
Anticholinergic used as anti-emetic
Hyoscine
Anti-emetic associated with QT prolongation
Ondansetron
Anti-emetic that causes extrapyramidal symptoms
Prochlorperazine
Antiemetic with limited value in opioid induced vomiting
Metoclopramide
Benefit of an epidural anaesthesia
targeted at the area of the body where the pain is
5 potentially catastrophic complications of an epidural
- permanent nerve damage
- intravascular injection
- complete spinal injection
- epidural abscess
- epidural haematoma
What is nociceptive pain
Physiological pain
What is neuropathic pain
Pathological pain - arises from some fault or change in the nervous system.
Drugs used in neuropathic pain
TCAs -amitriptylline
Anticonvulsants - Gabapentin, (Pregabalin - use after other 2)
what changes happen to the nervous system to cause neuropathic pain
amplification of signals in the dorsal horn (central sensitisation)
increased number of nociceptors in the periphery
cross connections in the nerve
loss of descending inhibition
examples of NSAIDS and mechanism of action of NSAIDs
ibuprofen, diclofenac, naproxen
classified by whether they block COX1, COX2 or both
above are non-specific
why do NSAIDs cause AKI
block production of prostaglandins (anti-inflammatory effect)
however prostaglandins dilate the renal arterioles
Timings of acute and chronic pain
acute < 3 months
chronic > 3 months
How does Lidocaine work
Local anesthetic that blocks Na+ channels
Therefore the neurones cannot depolarise
Paracetamol mechanism of action
Unclear
?COX3 inhibitory effect
NSAIDs mechanism of action
anti-inflammatory analgesics by blocking prostaglandin production
what functions do prostaglandins play a role in
gastric mucosal production
renal function
bronchodilation
platelet adhesiveness
locations of opioid receptors in the body
CNS pituitary GI system Periacqueductal grey dorsal horn of the spinal cord
How do pain signals travel from the periphery to the spinal cord
Nociceptors
Pain neurotransmitters
ATP
Glutamate
Substance P
3 main classes of opioid receptor
mu, kappa, delta
Tramadol mechanism of action
binds weakly to mu opioid receptors
inhibits noradrenaline reuptake
Mechanism of action of codeine
Codeine itself doesn’t have any opioid action
it is metabolised to morphine
Morphine mechanism of action
potent mu opioid agonist
Analgesic ratio of Oxycodone and morphine
Oxycodone has a higher bioavailability than morphine
Ratio of approx 1:2
Oxycodone SR 10mg = MST 20mg
Oxycodone immediate release 5mg = Oramorph 10mg
What is Fentanyl
short-acting and faster onset duration opioid than morphine
