L20-21 Pain Management Flashcards
most challenging pain to treat
neuropathic pain
- relative resistance to opioids
cancer pain is usually acute/chronic?
chronic
- hard to manage at end of life
- progressively more symptomatic, req bg pain control
most widely used non-opioids
paracetamol
use of codeine in renal/hepatic impairment
try to steer away
which opiate least potential for abuse
tramadol
nociceptors
specialised neural receptors in the brain
small myelinated A-delta fibers carry signals for
mechanical and thermal stimuli
C fibers carry signals for
all 3 (mechanical, thermal, chemical) stimuli
nociceptive somatic pain
- site is tender
- pain is localised to injury site
- constant and sometimes throbbing or aching, stabbing or pressure
- skin, muscle, bone
where does nociceptive visceral pain originate from?
viscera, mediated by stretch receptors
nociceptice viscera pain
- poorly localised, referred to a distant cutaneous site which may be tender
- deep, dull, cramping, gnawing
- organ or viscera
neuropathic pain
- burning, squeezing, tingling, shooting, electric/shocking pain, sharp
- no area of tenderness or area of exquisite sensitivity to normal innoculus stimuli
- resistant to opioids
tapentadol
new, not meant for chronic cancer pain
why is aspirin generally avoided?
irreversible antiplatelet effects
NSAIDs precautions
- elderly: >65yo
- bleeding disorder
- asthma, bronchospasm
- gi diseases (ulcer, bleeding)
- cv disease
- renal or hepatic dysfunction
- receiving anticoagulants
NSAIDs side effects
- GI
- reversible platelet inhibition
- renal effects: edema, htn, renal failure
- cns: headache, dizziness, nervousness and visual disturbance
- cv effects: edema, cv accident, htn, MI
- hypersensitivity rxn
- hematological: hemolytic anemia, pancytopenia, thrombocytopenia
pentazocin
agonist at kappa, antagonist at mu
- not available in sg
which side effect of codeine gets better?
drowsiness
- constipation gets worse
adm of morphine w food may
increase F, 35% after high fat meal
is morphine or fentanyl more potent?
fentanyl, approx 100x
fentanyl onset of action
v fast
- im: 7-15min
- iv: almost immediate
(highly lipophilic)
TD fentanyl indicated for pt w
- intolerable undesirable SE from morphine
- renal failure
- dysphagia
- tablet phobia or poor oral compliance
