2. Chronic Non-Malignant Pain MT1 Flashcards
know the three factors that contribute to an individuals health based on the biopsychosocial model of pain
BIO
1. biology (e.g. pain)
PSYCHO
2. psychology (e.g. mental health treated helps with the pain)
SOCIAL
3. social context (e.g. social determinants of health)
what are the three main types of pain and any subtypes of those
- Acute pain (<30 days)
- subacute pain (1-3 mths)
- Chronic (>3mths)
- nociceptive pain
- neuropathic pain
this is a type of pain caused by damage to the body tissue; it usually feels sharp, aching or throbbing.
nociceptive pain
this type of pain can occur when your nervous system is injured or not working properly; it is often characterized as being a shooting or radiating pain
neuropathic pain
what are some factors that need to be considered when choosing a pain medication for a patient?
- patient choice
- cost, access, insurance coverage
- patient characteristics (age, weight, renal/hepatic function, comorbidities)
- severity/pattern of pain
- type of pain/diagnosis
- response to prior drugs
- therapeutic drug monitoring
- pharmacogenomics (drug receptors, drug metabolism)
know some examples of peripheral vs central neuropathic pain
PERIPHERAL
- carpal tunnel syndrome
- nerve trauma
- phantom limb pain
- peripheral neuropathies (e.g. HIV related, chemotherapy-induced, diabetic neuropathies)
CENTRAL
- central post-stroke pain
- spinal cord injury pain
- brain injury
- multiple sclerosis (MS)
what do “SMART” treatment goals stand for?
S - specific!!!!!
M - measurable
A - action oriented
R - realistic
T - time bound
what are the first line options for management of neuropathic pain
VOLTAGE GATED ALPHA2 LIGAND
gabapentin/pregabalin
SERATONIN-NE REUPTAKE INHIBITORS (SNRI)
duloxetine/venlafaxine
SECONDARY AMINE TRICYCLIC ANTIDEPRESSANTS (TCA)
nortriptyline, amitriptyline)
what are the second line options for management of neuropathic pain?
Tramadol or opioid analgesics
what are the third line options for management of neuropathic pain?
Cannabinoids
If a first line agent for managing neuropathic pain is not quite successful, what are some options that may be considered before trying a second line option?
- switch to another first line agent
- try combining first line agents
what are the three options when combining TCA’s, SNRI’s and gabepntinoids?
- TCA first then add pregabalin
- Pregabalin first then add TCA
- Duloxetine first then add pregabalin
what is the time to effectiveness for an optimal response at any particular dose of an analgesic?
2-4 weeks
When adding agent from another class to help increase analgesia, what should be monitored, especially when combining a TCA & SNRI?
adverse effects!!!!! combining TCA & SNRI can increase risk of serotonin syndrome!
this is a first line agent for managing neuropathic pain; blocks the reuptake of serotonin (5HT) & norepinephrine (NE).
- is useful for concurrent conditions such as insomnia and depression
ADVERSE AFFECTS:
- anticholinergic (dry mouth, constipation, urinary retention in BPH, tachycardia)
- delirium
- orthostatic HYPOtension
- lower seizure threshold
- sexual dysfunction
- QT prolongation and cardiac arrhythmia
e.g. amitriptyline, nortripyline and desipramine
tricyclic antidepressants (TCA’s)
this is a first line agent for managing neuropathic pain; decreases neuronal excitability
ADVERSE EFFECTS:
INCREASED RISK OF OVERDOSE WITH OPIOIDS
- weight gain
- edema
- cns sedation
GABA derivatives
- pregabalin (BID dosing/less CNS side effects)
- gabapentin (TID dosing)
this is a first line agent for managing neuropathic pain; blocks serotonin (5HT) and norepinephrine (NE). useful for concurrent conditions such as anxiety and depression
ADVERSE EFFECTS:
- GI
- sleep disturbance
- CNS drowsiness
- increase BP (at high doses)
e.g. duloxetine and venlafaxine
*duloxetine is also indicated for chronic low back pain and fibromyalgia
SNRI
this is a second line agent for managing neuropathic pain; metabolized by CYP 2D6 to active metabolite
- weak SNRI thus does not work that well for neuropathic pain; risk of serotonin syndrome!!
- weak mu receptor agonist thus risk of addiction, respiratory depression and cns adverse effects
Tramadol
this is the drug of choice for Trigeminal neuralgia (severe facial pain) and is 4th line for chronic pain. it is a strong CYP450 inducer and autoinducer (metabolizes itself - drug works at first then stops working thus need to increase dose).
ADVERSE EFFECTS:
BONE MARROW SUPPRESSION and risk of infections (should get WBC’s checked
- hyponatremia
- hepatitis
carbamazepine
this is a second line option for postherpetic neuralgia (common complication of shingles - burning pain of nerves and skin) and is fourth line for chronic pain. it is a sodium channel blocker. most effective for !!Localized!! neuropathic pain; minimal systemic absorption
supplied as an ung (apply TID-QID prn)
Topical anesthetics (topical lidocaine)
this is a fourth line option for managing neuropathic pain. is used for post-herpetic neuralgia and hand osteoarthritis. it acts by desensitizing pain receptors.
this medication is made from chili peppers therefore wear gloves or wash hands after application.
comes in strengths of 0.025%, 0.05% and 0.075%
AE: local burning, stinging and erythemia
topical capsaicin
this is a third line option for managing chronic neuropathic pain.
AE: dizziness, fatigue, nausea, euphoria, impaired memory, disturbance in attention, psychosis and addiction.
should start with a low dose of a non inhaled option
cannabinoids
cannabinoids are not recommended for those at high risk of major harms including:
- have a history or a high risk of psychosis
- have a history or high risk of substance use disorder
- are pregnant or breastfeeding
- are under the age of 21
what are some options to manage neuropathic pain in pregnant women?
non pharm!!!!!
- acetaminophen
- NSAIDs (ibuprofen/naproxen) avoid in third trimester
- topical lidocaine (limited systemic absorption)
- amitriptyline
- try to avoid opioids, if only option use at lowest dose for shortest period of time due to neonatal withdrawal and rest. depression
what should be the first recommendation when considering therapy for patients with chronic non-cancer pain?
We recommend optimization of non-opioid pharmacotherapy and non-pharmacological therapy first.
what should be the recommendation for patients with chronic non-cancer pain, without current or past substance use disorder and without other active psychiatric disorders, who have persistent problematic pain despite optimized nonopijoid therapy
we suggest ADDING a trial of opioids rather than continued therapy w/o opioids
true/false: opioids are stimulants
false - opioids are depressants
this opioid should be avoided in renal insufficiency
morphine