Pain Flashcards
1
Q
Pain definition?
A
unpleasant sensory and emotional experience associated w/ or resembling that associated w/, actual or potential tissue damage
2
Q
Is pain a symptom or diagnosis?
A
Both
Ex: flank pain –> UTI
Idopathic pain
3
Q
Ratio of ppl w/ chronic pain in Canada?
A
1 in 5
1 in 3 over 65yrs old
4
Q
who has highest prevalence of chronic pain?
A
women over 65
5
Q
Race in Canada w/ highest prevalence of chronic pain?
A
indigenous
6
Q
Model of pain used today?
A
biopsychoscocial;
biological, sociological, psychological
7
Q
Acute pain characteristics?
A
< 3 months
organic cause common
pain reduction is goal
usually not med dependant
psych usually not present
environmental factors not usual
depression uncommon
insomnia not usually
8
Q
Chronic pain characteristics?
A
3-6 months +
organic cause may not be present
functionality is goal
med tolerance common
psych often a major concern
significant environmental
depression common
insomnia common component
9
Q
Nociceptive pain?
A
arise from damage to body tissue
sharp, aching, or throbbing pain
Ex: burn
10
Q
Neuropathic pain?
A
direct damage to nervous system, usually peripheral
burning, shooting/radiating, tingling, numbness
Ex: shingles pain
11
Q
Nociplastic pain?
A
change in way sensory neurons function rather than direct nervous system damage; neurons become more responsive
similar to neuropathic pain
Ex: fibromyalgia
12
Q
Somatic pain?
A
arises from: skin, bone, muscle, or connective tissue
Sharp, hot, stinging, or throbbing pain
Locallized w/ surrounding tenderness
Ex: burn, laceration, arthritis
13
Q
Visceral pain?
A
arises from internal organs
dull, ramping, colicky, gnawing, aching, squeezing, pulsing pain
poorly localized
Ex: pancreatitis, peptic ulcers
14
Q
Nociceptive pain pathopysiology?
A
Transduction: stimulation of noxious stimuli, cytokine and chemokine activate nociceptors
Conduction: chem signals converted to electrical signals and AP produced along alpha-delta and C nerves to spinal cord
Transmission: movement of impulses along spine including more chemical signals w/ glutamate and substance P
Perception: signals recieved by thalamus, make pain conscious
Modulation: signals can be made stronger w/ glutamate/ Sub P or inhibited by endogenous opiods like GABA, NE, and 5HT
15
Q
Which is the fast channel in conduction?
A
alpha-delta
16
Q
WHich is the slow channel in conduction?
A
C
17
Q
Pain produced by alpha-delta stimulation?
A
sharp, localized
18
Q
Pain produced by C-nerve?
A
achy, poorly localized
19
Q
Receptor activation involves which channels?
A
voltage-gated Na channels
20
Q
Channels used in transmission to regulate excitatory NTs?
A
N-type voltage-gated Ca channels
21
Q
What acts as the relay station in the brain?
A
thalamus
22
Q
where does perception occur?
A
higher cortical structures
23
Q
Modulation drugs that strengthen pain signals?
A
Glutamate
Substance P
24
Q
Modulation drugs that decrease pain signals/inhibt
A
endogenous opiods
GABA
NE
serotonin
25
Is there noxious stimuli in neuropathic pain?
No
26
Peripheral pain characteristics?
PNS
sharp, shooting/radiating, tingling, freezing, burning, itching pain
generally localized with nerve fibre
27
Central pain characteristics?
CNS
shooting/radiating, tingling, freezing, burning, itching pain
poorly localized
28
Acute pain treatment approach?
Assess pt
Select treatment: most effective analgesic with fewest AE's, lowest dose for shortest duration, scheduled for first few days then prn
Identify non-pharm strategies
Educate pt
Communicate and document plans for transition
29
Non-pharm therapies for acute pain?
education
distraction and relaxation
positioning
cold <48hrs post injury
acupuncture
exercise
RICE
heat >48hrs psot injury
massage
TENS
30
Acet dosing?
325-500-650-1000mg q4-6h, max of 4g/d
Chronic max is 3.2g/d
31
NSAIDs MOA and dosing?
inhibtion of COX1 and COX2, decreasing formation of PG precursors
Ibu: 400mg po q4h
Naproxen: 250-375-500mg po BID
32
Opiods dosing and MOA?
bind opiod receptors, suppress neuronal firing
less than50-90 MEQ/d
33
Child acet dosing
10-15mg/kg/dose q4-6h
max 75mg/kg/d or 4000mg which ever is lower
34
CI's of NSAIDs?
CKD
CrCl under 40mL/min
hyperkalemia
cirrhosis/ liver impairment
GI ulcers
IBD
uncntrolled HF
MI
thrombocytopenia
transplant
35
ASA dosing?
<300mg/d to reduce platelet aggregation
300-2400mg/dantipyretic and analgesic (325-600mg po q4h prn)
2400-4000mg anti-inflam
4000mg max/d
36
Diclo dosing?
50mg po BID
75-100mg SR po OD
max 100mg/d
37
ketorolac dosing?
10mg po QID prn
max 40mg/d, 5 days use limit b/c increase GI bleed
38
Naproxen sodium vs naproxen base max difference?
NS: 1500mg/d
NB: 1000mg/d
39
Which COX enzyme inhibtion is cardioprotective?
COX-1 inhibition (low dose ASA)
40
NSAID/COXIB that show increased CV risk?
Diclo >=150mg/d
Meloxicam
Celecoxib >200mg/d
Rofecoxib
Valdecoxib
41
Mechanism of how NSAIDs increase BP/ Cardiac risk?
Vasoconstrict, decrease renal blood flow, increase Na proxismal reabsorption
42
How are NSAIDs a GI risk?
COX-1 inhibtion leads to:
decreased PGs
decreased gastroduodenal mucosal protection
increased GI ulcer risk
43
NSAID GI risk factors?
age>60
comorbid conditions
history of GI bleeds or presence of H. pylori
multiple NSAIDs
high dose NSAIDs
SSRI, anticoag, antipaltelet therapies
HF
44
How to manage NSAID GI risk?
add misoprostol or PPI
--> arthrotec 75
--> Vimovo
45
Why do NSAIDs pose a renal risk?
COX1/COX2 inhibition leading to vasoconstriction of afferent arteriole
46
Advantage of Celecoxib?
COX-2 selective; reduces GI risk, minimal platelet effect
47
Celecoxib must be reduced in poor CYP_____ metabolizers
2C9
48
Celecoxib dosing?
400mg po for first day single dose
200mg po once daily for up to 7 days, max dose of 400mg/d for up to 7days
49
NSAID/COXIB DI's?
anti-HTN effect (HTN drugs)
lithium, methotrexate, steroids, tenofovir, warfarin (increase= toxicity)
Heparin, warfarin, corticosteroids, SSRI (increase GI risk)
ACEI and ARB, diuretics increase nephrotoxicity
Decrease ASA efficacy if co-adminsitered
50
WHO ladder?
Nonopiod(acet, ASA, NSAIDs)
Weak opioid (Codeine)
Strong opioid and nonopiod (morphine, hydromorphone, fentanyl)
51
Drug used in pregnancy for pain?
Acet is safest, others not recommended
52
Chronic secondary pain?
diagnosed when pain orginates as a symptom of another underlying health condition
53
4Ps of pain treatment?
Prevention
Psychological
Physical
Pharmaceutical
54
WHat population is acet thr first choice for in chronic use?
Dementia b/c effective and safe in this population
55
What medication has been newly added to low back pain treatment?
Duloxetine (SNRI)
56
stepwise approach to neuropathic pain treatment?
Gabapentinoids (TCAs, SNRIs)
Tramadol or opioids
Cannabinoids
Forht line agents?
57
Amitriptyline dosing?
25-100mg/d HS
58
Duloxetine dosing?
40-60mg/d
59
Venalfaxine dosing?
75-225mg/d
60
Desvenlafaxine dosing?
200-400mg/d
61
pregabalin dosing?
300-450mg/d divided BID or TID
62
Gabapentin dosing?
1800mg/d (900-3600mg divided TID or QID)
63
Gabapentinoid MOA?
block release of excitatory NTs by binding to specific Ca channels in CNS
64
AEs of gabapentinoids?
dizziness
drowsiness
N/V
mood changes
tremors
nystagmus
ataxia
peripheral edema
wt gain
65
DIs of gabapentinoids?
CNS depresants
anticholinergics
Serotonergic agents and pontentiators
66
How are gabapentinoids eliminated? bioavailability?
100% renal
F is inversley proportional to dose; F goes down as dose goes up
67
How must gabapentinoids, TCAs and SNRIs be d/ced?
Tapers to avoid withdrawal
68
TCA MOA?
inhibits reuptake of serotonin and NE, blocks sodium channels, blocks N-methyl-d-aspartate (NMDA) agonist induced hyperalgesia
69
AEs of TCAs?
anticholinergic;
dry mouth
dry eyes
constipation
urnie retention
sedation
confusion
QT prolongation
postural hypotension
70
CIs of TCAs?
If MAOI used in past 7 days
severe liver impairment
71
TCA DI's?
CYP2D6 substrates
CNS depressants
anticholenergic
serotonergic
antipaltelet
NSIADs
bupropion
carbamazepine
cyclobenzaparine
72
Are TCA dosing for pain and depression te same?
no, pain usually 1/3 to 1/5 the dose of depression dosing
73
MOA of SNRIs?
inhibit reuptake of serotonin and NE at neuronal junctions, Duloxetine has weak inhibiton of dopamine reuptake
74
AEs of SNRIs?
drowsiness
sedation
cosntipation
hypotension
increased HR/BP
hyponatremia
75
CI of SNRIs?
MAOI use in past 7 days
76
DI's of SNRIs?
Duloxetine: CYP2D6 inhibtors
Venlafaxine: CYP 2D6 inhibtors
Serotonergic agents
antiplatelets and NSAIDs
smoking
77
at what dose does venlafaxine inhbit NE reuptake?
>225mg
78
Timetable for full analgesic effect in neuropathic pain?
up to 6 weeks once titrated to target dose
79
Best treatment for Nociplastic pain?
exercise
80
Is an opiate and opioid?
Yes, opiates are naturally derived (opium, morphine, heroin, codeine) where as opioids are synthetic or semi-synthetic (ex fentanyl)
81
Which opioid receptor is responsible for over dosed stopping breathing?
mu
82
mu receptor characteristics?
analgesia****
euphoria, physical dependence, respiratory depression, reduced GI motility, sedation
83
delta receptor characteristics?
analgesia, euphoria, physical dependance
84
kappa receptor characteristics?
analgesia sedation, mood?, Not physically depedant.
85
Which receptor is NOT physically dependant?
Kappa
86
What occurs in the presynaptic neuron when binding of the opioid receptors?
decreases Ca influx
decreases transmiter release
87
What occurs in the postsynaptic neuron when the mu receptor is bound?
increase in K conductance
88
opioid MOA pharmacsit perspective?
opioid molecule bind to opioid receptors in CNS and PNS supressing neuronal firing from the presynaptic neuron and also inhibit postsynaptic nerves in some areas, altering transmission and perception of pain
89
opioid MOA patient explanation?
opiods work in the brain and nerves to quiet and slow down pain signals, making it feel like there is less pain
90
Opioid indications?
severe acute pain associated w/ surgery or medical conditions
treatment o chronic/terminal cancer pain
management of dyspnea in chronic lung diseases
91
Advantages of opioid use in chronic non-cancer pts?
potent analgesic effect
fast onset
relatively low risk of major organ toxicity
92
Disadvantages of opioid use in chronic non-cancer?
AEs:
- CNS depression
- falls/fractures
- constipation
- apnea
- hypogonadism
- hyperalgesia
- dependence
Risk of diversion
Tolerance
long term benefit evidence is lacking
93
Strong reccomendation?
indicates that almost all fully informed pts would choose the recommended course of action
94
Weak recommendation?
indicates that the majority of informed pts would choose suggested course of action but, an appreciatable minority would not.
95
duration of IR products?
4-6hrs
96
Q12hr products?
oxycodone
hydromorphone
morphine
97
Q24h products?
Morphine
Tramadol
98
Which buccal/sublingual tablets have a very short duration?
fentanyl (fentora)
99
Bucall or sublingual option that is long duration?
buprenorphine w/ naloxone (Suboxone)
100
duration of therapy of suppository? Drug?
4hrs
oxycodone (supeudol)
101
Which transderma option is Q72hrs?
fentanyl patch
102
WHich trandermal option is Q7d
buprenorphine patch
103
Which opioid is a subQ monthly injection?
buprenorphine
104
Injectable opioids?
morphine
hydromorphone
codeine
fentanyl
buprenorphine
105
Which morphine metabolite is active analgesic?
morphine-6-glucuronide
106
WHich morphine metabolite is not active analgesic?
morphine-3glucuronide
107
At what CrCl should morphine be monitored closely/ avoided?
20-30mL/min
108
Morphine MEQ?
1
hehehehehe
109
Codeine MEQ?
0.15
110
what would 200mg of oral codeine equate to of oral morphine?
30mg (200mg x 0.15)
111
WHich enzyme converts codeine to morphine?
CYP2D6
112
Factors that can cause codiene toxicity?
ultrarapid CYP2D6 metabolism
CYP3A4 inhibition
renal failure
113
Contraindications of codeine?
12 or under
18 or under post tonsilectomy and or adenoidectomy
114
What dose is codeine antitussive?
>=15mg q4-6h
115
Codeine CR dosing?
intial: 50mg q12h
2 day minimum increase interval
50mg/d suggested dose increase
max dose: 300mg q12h
116
Codeine IR dosing?
Intial: 15-30mg q4h prn
minimum 7 day increase interval
suggested dose: 15-30mg/d
Maximum dose: 600mg/d or acet max 4g/d
117
MEQ of oxycodone?
1.5
118
20mg oxycodone morpine equivalent?
30mg
119
Metabolizer of oxycodone?
CYP3A4 major
CYP2D6 minore to active metabolite
120
Characteristics of oxyneo?
forms gel when wet
difficult to break tablets
121
Percocet ingredients?
5mg oxycodone
325mg acet
122
Percodan ingredients?
oxycodone 5mg
ASA 325mg
123
Targin ingredients?
oxycodone
naloxone
124
Oxycodone CR dosing?
Intial: 10mg q12h
minimum 2 days increase interval
suggested: 10mg/d
125
Oxycodone IR dosing?
5-10mg q6h prn max 30mg/d
minumum increase interval 7d
suggested: 5mg/d
Max: acet 4g/d (combo product)
126
Hydromorphone MEQ?
5
127
what does 1 mg of hydromorphone correlate to morphine?
5mg
128
Whenis hydromorphone a good option?
in renal impairment
129
Hydromorphone CR/PR dosing?
CR: 3mg q12h max of 9mg/d suggested 3mg/d
PR: 4mg q24h maximum 8mg/d suggested 4mg/dH
130
Hydromorphone IR dosing?
1-2mg q4-6h prn
max 8mg/d
suggested 1-2mg/d
131
Interval increase time of hydromorphone CR/PR?
CR: 2d
PR 4d but 14d recommended
132
Interval increase time of hydromorphone IR?
7d
133
Tramadol MOA?
Mu receptor agonist
inhibits serotonin and NE reuptake
134
Binding affinity of tramadol for mu receptor in recpect to morphine?
~600x less potent than morphine
135
Metabolizer of tramadol?
CYP2D6 to active
136
Active metabolite of tramadol?
O-desmethyl tramadol
137
Risks of tramadol?
seizures
serotonin syndrome
hypoglycemia
QT prolongation
138
which tramadol CR is not maxed at 300mg? what is its maximum?
zytram XL
400mg
139
Tramadol CR suggested dose?
75-100mg q24h
140
Tramadol IR dosing?
max 400mg/d
sugested 25mg/d --> 1-2tab q4-6h
141
Which non-formulary drug is similar to tramadol?
tapentadol
142
Fentanyl MEQ?
~100
143
what would be the morphine equivalent of 25mcg/h fentanyl patch?
100mg morphine (in a day not per hour)
144
Controverse of switching with fentanyl patch?
converting TO patch is safe
but
Converting FROM patch is aggressive
145
Counselling points for fentanyl patches?
remove old patch before applying new patch
apply to clean, dry, non-hairy area
DO NOT shave hair if neede clip hair close to skin
do not use external heat on patch
146
How long to hold patch firmly on skin when applying
atleast 30 seconds
147
which fentanyl patch do you use when titrating or tappering?
12mcg/h
148
what kind of membrane are fentanyl patches?
matrix membrane
149
Methadone MOA for pain?
mu receptor agonist
NMDA receptor antagonist
150
Risks of t\methadone?
QTc prolongation
serotonin syndrome when combined with serotonergic drugs
151
Role of buprenorphine?
rotation from other opiods;
switching when at low doses.
151
What is the main difference in regards to the mu receptor with buprenorphine?
partial agonist; therfore cannot OD alone on buprenorphine
151
What is the maximum starting methadone dose?
30mg/d
152
Buprenorphine metabolized by?
CYP3A4
153
Does constipation and miosis (pinpoint pupils) get better over time with opioid use?
NO
154
General AEs with opioids used acutely?
sedation
respiratory depression
constipation
Nausea
Mioisis
itching/rash
155
How is itching/rash a pseudoallergy with opioids?
histamine release from cutaneous mast cells, not a true allegy or immunoresponse
156
When is toelrance to sedation of opioids generally seen?
3-4d,can take 10d but can also never go away
157
General AEs of opiods used long term?
hypogonadism
sleep apnea
opioid induced hyperalgesia
tolerance
dependence
toxicity
158
How do opioids cause hypogonadism?
influence HPA axis and HPG axis, morphine cuases a strong prgoressive decrease of cortisol plasma levels
modulate hormone release
159
Management of opioid induced hyperalgesia?
taper down, opioid rotation, switch to buprenorphine or methadone
160
SIgns of opioid OD?
difficulty walking, talking, staying awake
blue lips/nails
small pupils
cold/clammy skin
dizziness
confusion
drowsiness
chocking/gurgling or snoring sounds
not breathing
inability to wake up
161
What do you give for an opioid OD?
Naloxone
162
Naloxone MOA?
binds same receptors as opioids in the brain but, more tightly and dispalces opioids from the receptors.
No biological response from naloxone binding
163
Why might we need to give multiple doses of naloxone for an opioid OD?
wears off in 30-90 minutes so overdose may return
164
How much more potent is IV morphine over oral morphine? (all opioids)
2x
165
Physical withdrawl of opioid treatment?
clonidine
166
Sweating from opioid withdrawl treatment?
oxybutynin
167
