management of pain in practice Flashcards
what is pain?
complex
perceived by patient- variable thresholds
co-factors such as isolation, sleep, anxiety
many different types of pain
what ovservational changes would you make when assessing pain?
autonomic changes- pallor, sweatting
facial expressions
body movements- altered gait, pacing
verbilisations/ vocalisations- sigh/ grunt
interpersonal interactions- aggression, withdrawl
changes in activity patterns- wandering altered sleep
mental status changes- confusion, crying
what are the types of chronic pain?
nociceptive- oa
neuropathic- post-stroke
visceral- pancreatitis
mixed- lower back
what factors do you consider when treating pain?
type cause acute/ chronic? exacerbating/ relieving factors non-pharmacological managemnet
what is chronic non-cancer pain?
complex
perception of pain alt by social, psychological and cultural contex
what would you use for mild- moderate pain?
paracetamol
nsaids
cosibs
aspirin
weak opioids- codeine, dhc, tramadol- careful
if the patient was u16 how would you treat their pain?
paracetamol/ ibuprofen monotherapy
2nd line- alternate paracetamol and ibuprofen
what is the treatment regimenin adults for analgesic?
1- paractemol 1g QDS or ibuprofen 400mg TDS max of 2.4
2-paractamol and ibuprofen
3- alt nsaid eg naproxen 250-500mg BD
4- weak opioid eg codeine up to 60mg QDS with paracetamol +- NSAID
what do you consider when someone is taking NSAID?
1- dont use unless you have to
2- if you have to use them, use them wisely
3- consider gastroprotection in those at high risk
what would the dosing be of weak opioids?
codeine 30-60mg every 4 hours. Max 240mg in 24 hours
DHC- 30mg every 4-6 hours max 240mg in 24 hours
tramadol 50- 100mg every 4 hours. max 400mg in 24 hours
when would doses be lowered for weak opioids?
lower doses in elderly people, CKD, hypothyroidism and adrenocorticoid insufficency
what would the adverse effects be of weak opioids?
CNS depression- sedation
GI- nausea, vom, constipation
dependence /tolerance- limit use 3 dat OTC
tramadol- seizures, hallucinations, confusion, hyponatraemia, hypoglycaemia
what should you be cautious with all weak opioids?
caution with other CNS depressants and alcohol
when should you avoid MAOI?
avoid during use of weak opioids and for 2 weeks after stopping MAOI
why do you have to be cautious about tramadol?
drugs which can lower the seizure threshold
warfarin- raised INR
SSRI- serotonin syndrome and inc seizure risk
what are the strong opioids?
morphine- immediate or modified release
morphine paranteral
diamorphine
what are the main forms of oral morphine?
immediate release
oramorph - 10mg/5ml
oramorph concentrated 20mg/ml
sevredol tabs 10/20/0 mg
12 hour mr- MST or zomorph
24 hour- MXL
How would you dose in chronic pain?
initiation: 5-10mg every 4 hours of immediate release morphine, adjusted according to response
adjustments: increments of no more than 1/3 to 1/2 if the total daily dose every 24 hours
once the immediate release medication controls the pain, how do you stwitch to MR?
1- calculate the total daily dose of morphine
10mg every 4 hours= 60mg
2- give the same total daily dose but select the MR product and dosing frequency
eg 60mg daily= 30mg zomorph BD
3- calculate an appropiate breakthrough dose
what is the usual breakthrough dose- nb?
1/6-1/10th of the TOTAl daily dose of morphine
when would you give parenteral admin of opioids?
patient unable to swallow
GI dysfunction
how would you give parenteral morphine?
morphone IM/SC every 4 hours
if morphine IR to SC/IM give 50% of dose same frequency
if morphine MR to SC/IM
give 50% of total daily dose- divide and administer every 4 hours
how would you give diamorphine Parenterally?
highly soluble opioid
use for high dose SC injections
powder prep is diluted in a small vol of water for injections
what is the adverse effects of opioid analgesia?
euphoria drowsiness nausea and vom constipation tolerance addiction respiratory depression
what is oycodone?
semi synthetic analogue of morphine- different profile, strong kappa agonist, mu agonist
what are the metabolites of oxycodone?
partly metabolised to oxymorphone -caution in hepatic impairment
what is a fentanyl patch?
semi-synthetic analogue of morphine
- potent mu agonist
- highly lipophilic
what are the metabolites of fentanyl patch?
norfentanyl
how should you apply fentanyl patches?
apply to non-hairy, non- irritated and non-irradiated skin on a flat surface of the torso or upper arm
skin should be clearned with water only and the skin shoudld be dry befre the patch is applied
how long should fentanyl patches be applied for?
72 hours and the new patch should be applied to a differnt skin site after removal of the previous patch
how should fentanyl patches be evaluated?
evaluation should not be made before the system has been worn for 24 hours
prev analgesic therapy should be phased out gradually from time of first patch application
requires close monitoring for efficacy and adverse effects
Dose should be adjusted at 48-72 hour intervals in steps of 12-25 micrograms/ hr if necessary
how do you convert morphine doses to fentanyl?
m 30mg=12 patch m60=25 120-50 180=75 240=100
what is alfentanil?
synthetic derivative of fentanyl
more rapid onset, shorter duration of action
inacive metabolites
injection form
when is alfentanil used?
nd line- renal failurem SC prn short acting
what is buprenorphine patch?
semi-synthetic analogue of morphine
partial mu agonist, kappa antagonist, delta antagonist
what are buprenorphines metabolites?
norbuprenorphine and others
how does the potency of buprenorphien vary?
transtec- low dose strong opioid: 35mgc=30-60mg PO morphone
butrans- weak opioid 5mch=30-60mg po codeine
how long are the buprenorphine patches stay on for?
transtec= 4 days butrans= 7 days
when is buprenophine used?
2nd line
stable pain
concordance
low dose
what is hydromorphone
semi-synthetic analogue of morphine- potent mu selective agonist
metabolites: H3G and other minor ones
when is hydromorphone used?
2nd line mild-moderate renal impairment
when increaseing a dose what do you have to ensure?
not normally > 50/5 higher than the previous dose
what is neuropathic pain?
group of disorders characterised by various aetiolgies affecting the nervous system
infection, inflammation, metabolic disease, trauma or compression and chemical- induced nerve damage
what may the nerve lesion of neuropathic pain be related to?
CNS
PNS
would patients with neuropathic pain respond to anti-inflammatory/ opioid analgesics?
no
how does amitriptline work?
analgesic
blocks pre-synaptic re-upatke
NMDA receptor antagonist
what is gabapentin/ pregabalin?
same moa
chem analogue of GABA
binds to site in CNS, interact with alpha 2 delta calcum channels in CNS
what are gabapentin/ pregabalin licensed for?
neuropathic pain
what is duloxetine used for?
selective inhibitor of both serotonin 5HT and NA reuptake
how does duloxetine work?
possesses central pain inhibitory actions, probably related to itse potential of serotonergic and na activity in CNS
how is duloxetine metabolised?
extensively metabolised via VYP450 isoenzymes
what would be some examples of specalists neuopathic pain?
ketamine
methadone
what are adjunctive therapies you could have with opioids?
corticosteroids
bone pain
msk
bowel obs
what are some examples of non-drug pain relief?
application heat/cold massage TENS radiotherapy nerve blocks acupuncture psychological therapies
