exam 2 BONUS- pharm management of chronic pain Flashcards
treatment of chronic pain requires —-
physical medicine and pharmacological and psychological management protocols
most patients with chronic orofacial pain are ______ not _____
managed, not cured
limitations of pharm management of chronic orofacial pain
- empirical (clinical evidence)
- lack of randomized clinical studies
- challenging bc of fluctuations in conditions
- treatments assoc. with significant placebo effect
- lack of adequate pts with more specific condition
musculoskeletal orofacial pain
- myalgia
- myofacial pain
- TMJ
- arthritis
neuropathic pain
trigeminal neuralgia, other chronic pain
neurovascular disorders
- tension headache
- migraine
- cluster headache
drug categories for chronic orofacial pain
muscle relaxants -NSAIDs corticosteroids antidepressants antiseizure alpha adrenergic blockers triptains topical agents
treatment of musculoskeletal pain
- physical med and medications with emphasis on physical meds
- muscle relaxants for acute pain
- sleep and pain tied together
- blocking histamine relieves muscle stiffness and pain and promotes sleep
muscle relaxant examples
cyclobenzaprine (flexeril) carisoprodol (soma) methocarbamol (roboxin) diazepam (valium) baclofen (lioresal)
cyclobenzaprine (flexeril)
- mode of action unknown
- acts in CNS (locus coeruleus)
- increases norepinephrine inhibiting alpha motor neurons in ventral horn of spinal cord and causing decreased muscular tone
carisoprodol (soma) and methocarbamol (roboxin)
- relaxation of voluntary muscles through depressant action on CNS
- alterations in neuronal excitability involved
- reduce neuronal activity in brainstem, thalamus, and basal ganglia
- depression of spinal cord interneurons
diazepam (valium)
facilitates inhibitory actions of GABA on neurons
causes skeletal muscle relaxation
baclofen (lioresal)
analog of GABA and agonist for subset of GABA receptors (I.e. GABAb)
- may inhibit motor tone by decreasing release of excitatory amino acid transmitters
- may decrease calcium conductance and/or increase potassium conductance
- indicated for multiple sclerosis or traumatic spinal cord injury
- treatment for trigeminal neuralgia
ketorolac (torodol)
- acute and pre-emptive pain management (TMJ mobilization with lysis, lavage, and manipulations)
- can cause renal impairment
- should not be used in those with serum creatinine > 5 mg/dL
- limit to 5 days
- oral and parenteral
diclofenac sodium
- oral, topical gel and patch
- TMJ pain
- topical agent useful for TMJ capsulitis and myalgia associated with TM disorders
- oral diclofenac combined with misoprostol limits GI side effects
naproxen sodium
preferred NSAIDs for treatment of TMJ (500 mg bid due to longer half life)
adrenocorticosteroids treat—
acute inflammatory pain, headache and neuropathic pain
high dose tapered off
mechanisms of adrenocorticosteroids
modulation of GABAa receptors located outside BBB suppresses neurogenic inflammation
intra-articular therapy
reduces pain and swelling assoc with inflammatory disease of muscles and joints
cortisone and hydrocortisone
inject into joint
beneficial but diffuse out rapidly, lacking sustained effect
betamethasone
disodium phosphate ester used with insoluble acetate ester –> RAPID effect from phosphate ester and SUSTAINED effect from acetate ester
(adreno)
triamcinolone acetonide
low solubility and long duration
adreno
how many steroid shots can you get?
up to three with 4 week period between injections
when are antidepressants used?
- chronic orofacial pain can cause depression, anxiety, and reduced quality of life
- when other options are not enough and pain is accompanied by depression
most effective antidepressant
tricyclic antidepressant with effects on both serotonin and norepinephrine
(amitriptyline and nortriptyline)
nortriptyline
TCA
better tolerated than amitriptyline
duloxetine and venlafaxine (SNRIs)
used for chronic muscle pain and neuropathic pain
- patients with fibromyalgia
- improvements in quality of life but adverse effects for duloxetine, esp nausea and dry mouth
SSRIs examples
escitalopram
citalopram
fluoxetine
SSRIs are effective for treating ______ associated with _____
anxiety assoc with chronic neuropathic pain
SSRIs have more favorable adverse effects than _____
TCAs
treatment for chronic mastigatory myofascial pain
botulinum toxin type A
mechanism of botox
reduction in neurogenic release of pain causing substances such as glutamate, calcitonin-gene-related peptide and substance P by masticatory nociceptors to reduce pain in tender region of the muscle
common neuropathies in orofacial region
trigeminal neuralgia traumatic trigeminal neuropathy posterpetic neuralgia diabetic neuropathy cancer-induced neuropathy AIDs induced neuropathy
diagnostic criteria for trigeminal neuralgia
- episodic sharp pain with periods of remission
- no obvious local cause
- pain triggered with minor stimulation
- normal radiograph
- normal thermography
- positive block (nerve block relieves pain)
- sympathteic block does not define this disorder
most common neuropathy seen in orofacial region
trigeminal neuralgia
gold standard for treatment of trigeminal neuralgia
anti-seizure meds (carbamazepine, oxacarbazine, gabapentin)
carbamazepine
gold standard for trigeminal neuralgia
use dependent Na + channel blocker inhibiting repetitive discharges
-liver tests and complete blood count required
-extended release formulation
-induces CYP3A4 enzyme system which also accelerates its own metabolism; required dose adjustment 1-2 weeks of therapy
oxcarbazepine
- like carbamazepine but doesn’t induce liver enzymes
- better tolerability and safety margin
- does not require LFT and CBC monitoring but does require electrolyte monitoring for Na (can cause hyponatremia
- can be titrated more rapidly than carbamazepine –helpful in pts in acute trigeminal neuralgia
gabapentin
- analog of GABA but decreases hyperalgesia thru selective inhibition of subunits of voltage dependent L-type Ca++ channels
- this ion channel maintains mechanical hypersensitivity in neuropathic pain–suppresses but does not stop, neuronal activity
- side effects–relatively benign (drowsiness, nausea and fatigue) compared to other anti-seizure meds
are antidepressants more or less effective than carbamazepine?
less
how do adrenocorticosteroids work?
following nerve injury–> neuroma forms in proximal part–> neuronal sprouts–> spontaneous discharge–> steroids reduce neuronal activity bc of stabilization of neuronal membrane conductivity
-injection into neuroma
sodium channel subtype inhibitors
(local anesthetics)
- lidoderm (5% lidcaine patch) useful in management of peripheral neuropathic conditions
- FDA approved for post-herpetic neuralgia
treatment of abortive migraine
- nonopioid analgesic for mild to moderate
- triptan for moderate to severe migraine
- use of opioids and butalbital for migraine treatment is discouraged
short acting oral triptains
sumatriptan almotriptan eletriptan rizatriptan zolmitriptan *all similar in efficacy and speed of onset
____ triptan have faster onset of action than oral triptans
intranasal
_______ is the fastest acting and most effective triptan formulation
subcutaneous sumatriptan
prevention (prophylaxis) of migraine
topiramate, valproate, and beta blockers (propranolol, timolol, and metoprolol)
burning mouth syndrome
- burning pain in mouth every day for months+
- oral mucosa appears normal
- disorder of peripheral nerves with central brain changes
- no specific test
- most commonly seen in peri- and post-menopausal women
- no specific treatment
- poor prognosis but won’t get worse
symptoms of burning mouth
- burning, scalding, tingling in mouth or numbness
- dry mouth or altered taste
- painful
- usually tongue but can also be in lips or roof of mouth or throughout mouth
primary BMS
burning mouth syndrome
if tests do not reveal an underlying medical problem
-caused by damage to nerves that control pain and taste
secondary BMS
treating medical problem will cure secondary BMS
- hormonal changes
- allergies
- dry mouth
- meds
- nutrient deficiencies
- infection
- acid reflux
treatment of BMS
- depends on person
- go away when underlying medical condition is treated
- sip cold beverage, melt ice chips in mouth, chewing gum
- avoid irritating substance
- topical capsaicin and clonazepam
- systemic capsaicin for mouth –> gastric probs but good result
- combination of gabapentin with lipoic acid (antioxidant)
advantage of topical agents
direct application to tx area
decrease side effects
direct effects on local receptors may have greater benefits than systemic application
topical meds are incorp in ______ for skin app or _____ for oral app
- pleuronic lecithin organogel (PLO) for skin
- orabase for oral
PLO
pleuronic lecithin organogel
penetrates epidermal barrier, carrying the agent to the locus
-systemic admin also occurs
triamcinolone (kenalog)
orabase
composed of gelatin, pectin, and sodium carboxymethylcellulose in plastibase
capsaicin-responsive vanilloid receptors
on small-diameter unmyelinated nociceptors (C fibers)
- target of novel sites of drug action
- TRPV1 receptors
capsiacin action
causes release and eventual depletion of neuronal stores of substance P, eventually causing inhibition of neuronal ability to synthesize more SP
persistent application of capsaicin does what?
desensitizes chronic peripheral neuropathy, causing relief from pain
how is capsiacin applied?
intraorally
-with acrylic stent and 0.025% capsaicin mixed with orobase-b paste to give sticky quality to hold in place and limit dispersion throughout the oral cavity
topical agents examples
ketamine, eutectic mixtures of local anesthetics (EMLA) and 5% lidocaine patch (lidoderm)
