Pain Meds Flashcards
Which group of pain meds inhibit COX?
NSAIDs
What inflammatory mediator causes inflammation–>pain?
prostaglandins
What does COX 1 and 2 do?
use arachidonic acid to produce prostaglandins during inflammation
physiologic role in renal function
COX 1 in all tissues, COX2 induced
What drug irreversibly binds COX 1 and 2 to decrease prostaglandin and thromboxane A2?
aspirin
What to use aspirin for?
pain fever inflammation stroke MI prevention (via - Cox1 in platelets)
Side effects of aspirin
ulcer
bleeding risk
multiple drug interactions
Reye syndrome in kids with flu or chicken pox
increased serum creatinine d/t loss of prostaglandin effects in kidneys
What drug reversibly binds COX 1 and 2 to decrease prostaglandin synthesis?
ibuprofen
pain, fever, inflammation
What is the difference between naproxen and ibuprofen?
same MOA
naproxen has longer half-life (2 vs 12 hours)
Side effects of ibuprofen
fetal renal dysfunction–> oligohydraminos after 20 weeks
closure of ductus arteriosus after 30 weeks
increased risk MI and stroke
–> DONT USE IN CABG
increased risk of GI bleeding
What drug inhibits prostaglandin synthesis via COX2?
celecoxib
pain, arthritis, dysmenorrhea
Side effects of celecoxib
fetal renal dysfunction–> oligohydraminos after 20 weeks
closure of ductus arteriosus after 30 weeks
increased risk MI and stroke
–> DONT USE IN CABG
increased risk of GI bleeding (less with COX2 vs 1 and 2)
Why do you take aspirin 2 hours before other NSAIDS?
non-aspirin NSAIDS interfere with antiplatelet effects–> decrease protection against MI and stroke
Why d/c high dose aspirin 1 week before surgery/pregnancy?
increase risk of bleeding with warfarin, heparin, other anticoagulants
MOA of non-aspirin NSAIDS
inhibit COX1 and 2
pain, fever, inflammation
increased risk gastric ulcer, renal impairment, bleeding
different from aspirin:
- reversible effects
- increases risk of MI/CVA
use lowest effective dose for shortest possible time
Coxibs vs aspirin or non-aspirin NSAIDs
less gastric ulceration
selectively blocks COX2
doesn’t inhibit platelet aggregation–> no risk for bleeding
increased risk MI and stroke
Commonly used NSAIDs
aspirin celecoxib (celebrex) diclofenac ibuprofen (motrin) indomethacin ketorolac (toradol) naproxen (aleve, naprosyn)
What NSAID is recommended is a patient has cardiovascular risk?
naproxen
Contraindications for NSAIDs
CKD gastric or duodenal ulcer heart failure uncontrolled HTN allergy ongoing anticoagulant tmt
When to use acetaminophen
pain and fever
DOES NOT treat inflammation
Side effects of acetaminophen
med error/overdosing–> hepatotoxicity (depletes glutathione)
no GI, bleeding or renal risk
Suspected MOA of acetaminophen
activate descending serotonergic inhibitor pathways in CNS
tmt for acetaminophen toxicity
acetylcysteine
substitutes depleted glutathione
Increased risk of bleeding with acetaminophen and ____
warfarin
inhibits its metabolism
First line agents for neuropathic pain
calcium channel ligands
serotonin-norepi reuptake inhibitor (SNRI)
tricyclic antidepressant
amitriptyline
tricyclic antidepressant (inhibits NE and 5-HT reuptake)
treat neuropathic pain
Side effects of amitriptyline
SI in kids and ya
anticholinergic effects
increased bleeding risk
duloxetine
inhibitor of 5-HT and NE reuptake
weak dopamine reuptake inhibitor
treat neuropathic pain with concurrent depression
Side effects of duloxetine
SI (main)
N, dizziness, sweating, sexual dysfunction, insomnia/agitation, increased BP
pregabalin (Lyrica)
binds a2s subunit of CNS calcium channels (NOT GABA) to decrease excitatory AP
neuropathic pain a/w DM neuropathy, postherpatic neuralgia, fibromyalgia, partial seizures
gabapentin similar
Second line tmt for neuropathic pain
antiepileptic
opioid
tramadol
Second line for nociceptive pain
weak opioid, nonopioid and adjuvant (TCA, SNRI, anticonvulsant)
Third line for nociceptive pain
strong opioid, nonopioid and adjuvant (TCA, SNRI, anticonvulsant)
Third line for nociceptive pain
strong opioid, nonopioid and adjuvant (TCA, SNRI, anticonvulsant)
tramadol
partial u-opiate receptor agonist
block NE and 5-HT reuptake
severe pain, premature ejaculation, RLS
Side effects of tramadol
overdose/death via respiratory depression with med error
addiction, abuse
interact with CYP450 drugs
increase respiratory depression with use with benzo, other CNS depressants
What to use for patients not effectively treated with opioids or non-opioids in neuropathic pain?
tapentadol
mod-strong opioid agonist, blocks NE reuptake
Third/Fourth line tmt for neuropathic pain
3: NMDA antagonist, analgesic combo, baclofen/tizanidine
4: botox, intrathecal ziconotide
ketamine
noncompetitive NMDA receptor antagonist
dissociation/anesthesia, analgesia
dexmedetomidine
selective alpha 2 agonist in brainstem
– inhibit NE release
sedation, pain
clonidine
alpha 2 agonist for HTN and severe pain
ziconotide
N voltage calcium channel on dorsal horn afferent nerves–> block excitation to reduce sensitivity to pain
Side effects of ziconotide
severe psych sx, neuro impairment
increased risk for patient harm when used in error
When to use ziconotide
only for chronic severe pain
given intrathecal when refractory to other treatments
lasmiditan
5-HT receptor agonist
decrease stimulation of trigeminal system, treat migraine
ubrogepant
calcitonin antagonist
treat migraine with or without aura
dihydroergotamine
ergot alkaloid
migraine
cluster headaches
orthostatic hypotension
pelvic congestion with pain
Side effects of dihydroergotamine
contraindicated with potent inhibitors of CYP3A4
cerebral ischemia
ischemia of extremities
