Analgesia Flashcards
Sedative Agents
aka anxiolytics
sometimes same drug as hypnotic - low dose
Hypnotic Agents
higher dose anxiolytics - induce sleep
sedative/hypnotic ADRs general
Residual drowsiness, REM rebound (vivid dreams), Dependence, Tolerance, Excessive Depression (longterm), Respiratory Depression, Potential for abuse
elderly - CNS depression, Confusion, Falls - limit use
CNS depressants
Benzos
Benzo -like drugs (zolpidem)
Barbiturates
classes of sedatives/hypnotics
CNS depressants
Benzos
Benzo -like drugs
Barbiturates
other misc?
benzodiazepines
the pams and lams
the pams and lams
DOC for anxiety/insomnia
potentiates endogenous GABA (limit to CNS depression), lipid soluble xs BBB
avoid abrupt w/d
short t1/2
short term use only - potential for abuse (less than barbiturates)
no analgesia
indic: anxiolytic, anti-szr, anesthesia induction, alc w/d, insomnia, muscle spasms, acute agitation
avoid alcohol, opioids
ADR - CNS depression, Complex sleep behaviors
zolpidem (ambien)
“Benzo-like”
first choice for insomnia
same mechanism as benzos
okay during pregnancy - not encouraged (benzos xindic)
Ramelteon
melotonin agonist, rapid onset short t1/2
Barbiturates
powerful resp. depressants
high potential abuse
tolerance/dependence
liver enzyme inducer
no reversal agent- benzos preferred
Benzos
Have a greater margin of safety than the Barbiturates
Lower potential for abuse- BUT STILL ABUSED!
Less tolerance and dependence
Fewer drug interactions
Lower risk of respiratory depression
Opioid analgesics
most effective agent for severe acute pain
mimic endogenous opioid peptides
receptor activation: mu - strong activation, kappa - weak
sedation, euphoria, dependence, tolerance, decreased GI motility, respiratory depression, vasodilation - hypoTN
check BP, RR
tolerance develops to analgesia, euphoria, sedation, resp depression but not constipation and miosis
avoid anticholinergics - exacerbate constipation and urinary retention
Nonopioid
do not cause sedation
generally no dependence
Buprenorphine (suboxone)
agonist-antagonist
low abuse potential
analgesia ceiling
different MOA
Opioid interactions - antiemetics
FGA -phenothiazines - reduces N/V
Opioid interactions - clonidine
enhances opioid induced analgesia
Morphine
strong opioid (prototype)
increased effectiveness if admin’ed before pain level intolerable
first pass effect - oral dosing > perenteral
ADR: itching
Fentanyl
synthetic opioid 100x stronger than morphine
indic: need for fast action
transdermal patch for severe persistent (24 hrs slow release) - no heat pads
Meperidine (demerol)
rigors post surgery
not used anymore - short t1/2, many d-d, toxic metabolit
strong opioid
Methadone
strong opioid
very long half-life
different dosing for pain than for SUD
indicated for chronic pain, treatment of heroin SUD (DOT)
ADR: prolonged QT
CYP450 inhibitors raise levels
Hydromorphone (Dliaudid)
Strong opioid
less n/v than morphine
repiratory depression major concern - caution IV vs PO
Codeine
Similar to Morphine
less analgesia/resp depression
lower potential for abuse
more likely than others to cause constipation
Oxycodone
moderate to strong
high abuse potential
oral admin
in combo w/ aspirin - percodan
in combo w/ acetaminophen - percocet
Hydrocodone (Vicodin)
most widely prescribed
analgesia and antitussive
PO admin
Norco - w/ acetaminophen
cough - combo w/ antihistamines and decongestants
Pentazocine/Butorphanol
agonist/antagonist – produce less analgesia (ceiling) than morphine
with a lower potential for abuse
can precipitate w/d if given to opioid dependent
best practices opioids
schedule dosing
fixed schedule more effective than prn
prn dose for breakthrough and procedural pain
Naloxone
short t1/2, req rpt dosing
opioid w/d symptoms
early - agitation, anorexia, irritability, tremor, itching, gooseflesh
peak - violent sneezing, weakness, n/v/d, abd cramps, muscle pain, spasm, kicking movements
avoid by weaning
NSAIDs
COX inhibitors
ADR: GI bleeding, PUD, perforation, prolonged bleeding times, kidney damage, suppression of contractions, inc risk for MI, stroke
First Gen NSAIDs
Aspirin, Diclofenac, Ibuprofen
ADRs: GI upset (give with food), bleeding, GI bleed, peripheral edema (sodium/water retention)
aspirin protective for stroke/MI - all others may inc risk
Second Gen NSAID - celecoxib
less GI ulceration, still risk for renal impairment (from vasoconstriction)
risk for MI/stroke (vasodilation suppressed)
RA, acute pain, osteoarthritis, dysmenorrhea, post op pain
xind: pregnancy, sulfonamide allergy
inhibition of cox-2
suppresses inflammation, pain, fever, renal impairment
inhibition of cox-1
gastric ulceration, renal impairment, bleeding
Aspirin
ADR: gastric distress, bleeding, renal impairment, reye’s syndrome, hypersensitivity, erectile dysfunction
Cox1 - prevents MI and stroke - platelet aggregation
xindic - children (reye’s), pregnancy (suppress
spontaneous uterine contractions, induce premature closureof the ductus arteriosus, and intensify uterine bleeding), ED
can lead to acute irreversible kidney impairment
bronchospasms in asthmatics
Ibuprofen (non-aspirin NSAIDs)
reversible inhibition of COX
increased risk of MI/stroke
renal impairment
suppress inflammation, pain, fever
Ketorolac (toradol)
IV/IM NSAID
acute mod to severe pain - strong analgesia
effect equal to opioids
use ltd to 5 days
GI bleeding, PUD, kidney damage
xind: pre-op, PUD, GI bleed, intracranial bleed, l&d
tylenol toxicity
4g - max dose, OD 25g adult
leading cause of acute liver failure
accumulationg of toxic metabolite
12 -24 hrs - GI cramping, n/v
day 2 - no obvious s/s, relief, uop drops, hematura, pain URQ
48-72 hrs - hepatic necrosis irreversible
give acetylcysteine 8-10 hrs p/s OD
Acetaminophen
Non-narcotic with NO antiinflammatory effect
Suppresses COX in CNS - no peripheral effect
reduces pain, fever (not inflammation)
does not cause GI ulceration, does not suppress platelet aggregation, does not impair renal fxn, fewer d-d, no risk of reye’s
hepatic necrosis - OD - risk inc by undernourishment, alcohol, liver dx
rare - SJS, AGEP, TEN - rash - d/c
OD treated w/ acetylcysteine
best if given 8-10 hrs post ingestion
Tramadol
mod to severe pain
analog of codeine, not considered opiate
weak agonist mu
low pot abuse, resp depression,
ADR: sedation, dizziness, HA, constipation, seizures (rare)
Clonidine
alpha 2 adrenergic agonist
blocks nerve impulses that transmit pain signals
ADR: hypoTN, brady, rebound HTN, dry mouth, CNS depression
Dexmedetomidine
alpha 2 adrenergic agonist
used to facilitate sedation/analgesia
IV only
ADR: hypoTN, brady
Flumazenil
Benzo induced hypoTN, respiratory depression - reversal
Methylnaltrexone
opioid antagonist - selective MU in only GI tract
methyl group - does not x BBB
no decrease in pain control
ADR - abd pain, diarrhea, do not use in obstruction
Opioid induced constipation
Reye’s Syndrome
Liver injury, encephalopathy
esp in children
inc risk aspirin
Acetylcysteine
Acetominophen overdose/toxicity
PO or IV
best if given within 8-10 hours after ingestion (at least within 24hrs)
ASA poisoning
lethal dose 25g, child 4g
mild - tinnitus, CNS - dizzy, drowsy, confusion, hyperventilation -> resp alkalosis
progressed - initial inc –> resp depression, acidosis, dehydration, hyperthermia
severe anticoagulation
Stupor -> coma-> death r/t respiratory failure
trtmt: correct fluid/acid/base imbalance
alkanization w/ HCO3 to speed up excretion, dialysis
antagonists-agonists
Buprenorphine
pentazocine
butorphenol
