MSK/Pain Flashcards
what does NSAIDs stand for
Non-sterioidal anti-inflammatories
example for NSAIDs
Diclofenac, Naproxen (oral/topical), Ibuprofen, Etoricoxib
how does NSAIDs work
inhibit the prostaglandin synthesis by reducing cyclooxygenase (COX) mainly COX 2
what are the 2 isoforms of cyclooxygenase
COX 1 - constitutive form (always there) - stimulate prostaglandin synthesis which is essential to preserve integrity of gastric mucosa, maintain renal perfusion (by dilating afferent glomerular arterioles) and inhibit thrombus formation at the vascular endothelium
COX 2 - inducible form - expressed in response to inflammatory stimuli - stimulate production of prostaglandin which cause inflammation and pain
indication for NSAIDs
midl-moderate pain as required (alternative for paracetamol)
regular treatment for pain related to inflammation particularly of the MSK eg RA, severe OA
contra-indication for NSAIDs
severe renal impairment HF LF peptic ulcer disease GI bleeding cardiovascular disease renal impairment
where is NSAIDs eliminated from the body
liver
Side effect of NSAIDs
GI toxicity
renal impairment
inc risk of CV events
fluid retention
different NSAIDs have different side effects - non-selective COX 2 inhibitor have a greater risk than selective for CV event
Non-selective NSAIDs - lowest CV risks are ibuprofen and naproxen
interaction of NSAIDs
many drugs can cause increase adverse effect of NSAIDs
GI ulceration - low-dose aspirin, corticosteroid
GI bleeding - anticoagulants, SSRIs, venlafaxine (SSNRI)
renal impairment - ACE inhibitors, diuretics
in risk of bleeding - warfarin, reduce the therapeutic effects of antihypertensives and diuretics
how should pt take NSAIDs
with meals ideally with PPIs
what is an example of weak opioids
tramadol, codeine, dihydrocodeine
how does weak opioids work
so weak opioids like codeine and dihydrocodeine is metabolised in the liver and produce a small amount of morphine or dihydromorphine
they are agonist of opioid mu receptors
who might find codeine and dihydrocodeine ineffective ?
10% of white caucasians
what has been described as moderate opioids
tramadol which is a synthetic analogue of codeine
how does tramadol work
same as codeine but also work on serotonergic and adrenergic pathway and act as a serotonin and noradrenaline reuptake inhibitor
how does opioid mu receptor work
activation of this receptor in the CNS will reduce neuronal excitability and plain transmission
in medulla, reduce the response of hypoxia and hypercapnoea reducing the respiratory drive and breathlessness
by relieving pain, breathlessness and associated anxiety, opioids reduce sympathetic nervous system (fight or flight) activities
this in turn reduces the cardiac work and oxygen deman as well as relieving symptoms