L44- Pain Management Flashcards
list the types of pain
- nociceptive
- inflammatory
- neuropathic
- functional
define:
- (1) nociceptive pain
- (2) inflammatory pain
1- response to noxious stimulus – somatic or visceral
2- tissues damage occurring despite nociceptive defense system
define:
- (1) neuropathic pain
- (2) functional pain
1- damage or dysfunction of PNS or CNS (rather than pain receptor stimulation)
2- pain sensitivity due to abnormal processing or function of CNS –> in response to normal stimulus
define Acute Pain and the usual types of pain
- usually result of injury or surgery
- self-limiting pain
-usually Nociceptive, can be Neuropathic
define the types of Chronic Pain
All- persistent pain for mos-yrs // all pain types (nociceptive, inflammatory, neuropathic, functional)
Chronic Malignant pain: associated with progressive disease like AIDS, cancer
Chronic Non-Malignant pain: pain not associated with life-threatening condition, duration >6mos
correlate pain scale with mild, moderate, severe pain and include the general therapy for each pain categorization
Mild, 1-3/10: non-opioids +/- adjuvant
Moderate, 4-6/10: opioids (medium potency) +/- adjuvant and or non-opioid
Severe, 7-10/10: opioids (high potency) +/- adjuvant and or non-opioid
list the mild-to-moderate analgesics
NSAIDs, acetaminophen
codeine
tramadol
list the moderate-to-severe analgesics
-Morphine, oxymorphone, hydromorphone
- meperidine, fentanyl, levorphanol, methadone
- oxycodone, hydrocodone
mixed agonists:
- 2nd line: butorphanol, nalbuphine, buprenorphine
- 3rd line: pentazocine
(1) is first-line for OA
(2) is preferred in gouty arthritis
1- acetaminophen (NSAIDs if there are signs of inflammation)
2- NSAIDs
describe the principles to starting opioid therapy
-give orally at fixed intervals
-start at low dose and gradually inc to higher dose
(give next dose before previous dose effect has worn off)
-as pain subsides –> use prn
Breakthrough pain is defines as (1) and is often seen in (2) patients. (3) is usually given to relieve this pain, include dose and all formulations.
1- severe acute pain in background of chronic pain
2- cancer
3: Fentanyl at 5-15% normal dose (rapid and short acting agent)
- nasal spray, sublingual spray
- oral transmucosal lozenge (lolipop)
- immediate release transmucosal tablet, effervescent buccal tablet
- buccal soluble film
describe analgesic ceiling effect
Tolerance to agent where higher doses:
- do not relieve pain or improve Sxs
- toxicity continues to inc with higher doses
NOTE:
- Pure Opioid Agonists – no analgesic ceiling effect
- Non-Opioids – have analgesic ceiling effect
- Mixed Agonists – have analgesic ceiling effect
describe PCA and the associated analgesics
- self-administration of parenteral analgesics by Pt as needed
- Agents: morphine, hydromorphone, fentanyl, methadone
list the two analgesics that are not recommended for routine dosing and explain for each
Meperidine: (1-2 day use in young Pts)
-1/2 life 3hrs –> metabolite Normeperidine 1/2 life 15-20hrs –> dysphoria, myoclonus, seizures
Mixed Agonists:
- ceiling effect
- only for naive-opioid Pts => withdrawal reaction if not
- psychotomimetic effects w/ pentazocin, nalbuphine, butorphanol
list the 4 common and 1 uncommon AEs of opioids that can be modulated with other drugs
Common:
- pruritus
- sedation
- n/v
- constipation
Uncommon: respiratory depression
pruritus from opioids occurs in response to (1) actions and can be managed via (2) administration
1- release of Histamine from mast cells
2- hydroxyzine, diphenhydramine
- (1) describe sedation effects of opioid
- (2) may be used if needed to prevent this sedation
1- usually disappears with tolerance over several days
2- Methylphenidate, Modafinil if sedation persists
- (1) describe nausea and vomiting effects of opioids
- (2) may be used to prevent and treat n/v
1- usually disappears with tolerance over w/in a few days
2- hydroxyzine, metoclopramide, prochlorperazine
(1) is the almost hallmark or universal side-effect of opioid use, so (2) is often given at the start of opioid therapy
1- constipation; doesn’t really dec that much with tolerance
2- laxative — stool softener if needed
Tolerance to (1), an uncommon opioid side-effect, develops quickly, although if severe enough, (2) is administered.
1- respiratory depression
2- naloxone
______ are the mainstay treatments drugs for neuropathic pain
Antidepressants: TCAs, SNRIs
Anticonvulsants:
- gabapentin, pregabalin
- carbamazepine, oxycarbazepine
list the main or common causes of Neuropathic pain
- diabetic peripheral neuropathy
- postherpetic neuralgia
- cancer
- spinal cord injury
- MS
- trigeminal neuralgia
explain why antidepressants (and which agents) help treat neuropathic pain
- Descending pain pathway is Serotonergic and Noradrenergic –> inhibits pain signaling
- Anti-depressants modulate and inc 5-HT and NE transmission
-TCAs and SNRIs modulate both 5-HT and NE –> so very useful for modulating descending pain pathway [SSRIs not as effective since only works on 5-HT]
- (1) TCAs are commonly used for neuropathic pain
- (2) list the many AEs
1:
Tertiary- amitriptyline, imipramine
Secondary- nortriptyline, desipramine
2:
- Anti-mAChR: constipation, xerostomia, tachycardia, blurred vision, cognitive changes, urinary retention
- Anti-H1R: sedation, weight gain
- Anti-5-HT: sexual dysfunction
- Anti-α1: hypotension, reflex tachycardia
______ are the preferred TCAs, explain
Secondary Amines: nortriptyline, desipramine
- fewer anti-AChR effects
- fewer anti-H1R / sedation effects
- **critical for elderly population
Tertiary Amine are tend to be avoided, especially in older patients
TCAs are given cautiously in the following conditions….
- angle-closure glaucoma
- BPH, urinary retention
- constipation
- CV disease
- impaired hepatic function
TCAs are contraindicated in the following conditions….
- arrhythmias
- 2nd/3rd degree heart block
- prolonged QT
- recent acute MI
-severe liver disease
SNRIs:
- (1) agents
- (2) advantage over TCAs
- (3) AEs
1- venlafaxine, duloxetine
2- no antihistamine, antiadrenergic, anticholinergic activity as with TCAs —> fewer AEs
3- nausea, somnolence, sexual dysfunction
list the anticonvulsants used to treat neuropathic pain
- gabapentin, pregablin
- carbamazepine, oxcarbazepine
Gabapentin, Pregablin for neuropathic pain:
- (1) MOA
- (2) AEs
1- blocks V-gated Ca channels –> dec release of Glu, NE, substance P
2- dizziness, somnolence, peripheral edema
______ is drug of choice for trigeminal neuralgia
carbamazepine
______ is the advantage of oxcarbazepine over carbamazepine
near equal efficacy
better tolerated
Carbamazepine, Oxcarbazepine for neuropathic pain:
- (1) MOA
- (2) AEs
1- blocks V-gated Na channels –> dec sensory neuron firing
2:
- n/v, drowsiness, dizziness
- Rare: anemia
- Carbamazepine-induced leukopenia is uncommon and benign
list and define some of the common topical therapies for neuropathic pain
Lidocaine: localized peripheral neuropathy, particularly postherpetic neuralgia
Capsaicin:
- depletes substance P from terminals of C fibers
- high concentrations used for postherpetic neuralgia
Clonidine:
- α2 agonist (note- multiple routes of administration)
- for sympathetically maintained pain
Glucocorticoids as pain adjuncts:
- (1) is drug of choice, explain
- (2) are alternate agents
- used to improve (3) symptoms (in advanced illnesses)
1- dexamethasone
2- prednisone, methylprednisone
3- appetite, nausea, malaise, overall quality of life
list some of the predominant uses of glucocorticoids as adjuncts in pain therapy
- acute nerve compression
- inc ICP
-bone pain, visceral pain
- anorexia, nausea
- depressed mood
(1) is the main Bisphosphatase used for (2) pain, particularly in (3) conditions
1- Zoledronate (maybe pamidronate)
2- bone pain
3- bone metastasis, multiple myeloma
