Management of Acute Postoperative Pain Flashcards
according to International Association for
the Study of Pain, what is the definition of pain?
unpleasant sensory and emotional experience that arises from actual or potential tissue damage
types of causality of pain
- nociceptive
2. neuropathic
what type of pain do we normally tx in dentistry?
acute nociceptive pain
inadequate management of acute pain may cause what?
- anxiety
- increased sympathetic output
- poor rest
- inadequate oral intake
noxious stimulus causes cell damage and what to release?
chemical mediators
what happens when chemical mediators are released after a noxious stimulus?
- 1st order neuron impulse
2. peripheral nociceptors sensitized
what modulates the trigeminothalamic tract pathway?
opioids and non-opioids
how does analgesics modulate the trigeminothalamic tract pathway?
- by interrupting ascending nociceptive impulses
2. depressing impulse interpretation in CNS
what does NSAIDs block?
cyclooxygenases which activates prostaglandins that cause pain, inflammation and fever
common side effect of traditional NSAIDs
- stomach pain
2. heartburn
serious side effect of traditional NSAIDs
- GI toxicity
2. decreased renal fxn
why is traditional NSAIDs a relative contraindication for asthmatic patients?
shunt activity to lipoxygenase
if asthmatic pt takes ibuprofen, cyclooxygenase is inhibited –> activity has to go somewhere so goes towards lipoxygenase pathway –> a lot of leukotrienes are created which induces broncospasm and asthmatic rxns
absolute contraindications to NSAIDs
- allergy
- pregnancy
- erosive or ulcerative conditions of the GI mucosa
relative contraindications to NSAIDs
- asthma
- anticogulant therapy or hemorrhagic disorders
- compromised renal fxn
example of COX-2 selective NSAID
celecoxib (celebrex)
effect of celecoxib (celebrex)
- anti-inflammatory
- analgesic
- anti-pyretic
T/F: celecoxib (celebrex) protects normal physiologic processes
true
COX-2 activates what?
- prostaglandins
2. prostacyclin
effect of prostaglandins when activated by COX-2
- pain, inflammation, fever
2. renal fxn
effect of prostacyclins when activated by COX-2
- platelet inhibition
2. vasodilation
effect of prostaglandins when activated by COX-1
- gastric mucosal barrier
2. renal fxn
effect of thromboxane A2 when activated by COX-1
- platelet aggregation
2. vasoconstriction
why don’t we use COX-2 inhibitors exclusively to manage acute postoperative pain?
- poor efficacy in 3rd molar model
- expensive since it’s the only one option on the market
- increased embolic phenomena
when is COX-2 inhibitors contraindicated?
pts with sulfa allergy
mechanism of action of acetaminophen
believed to be prostaglandin synthesis inhibition in CNS
what are the effects of acetaminophen?
- analgesic
2. anti-pyretic
T/F: acetaminophen has anti-inflammatory effects
FALSE
which organ conjugates acetaminophen into non-toxic metabolites?
liver
what dosage can the liver no longer conjugate acetaminophen into non-toxic metabolites?
200-250 mg/kg/24 hr
what cyctochrome breaks down acetaminophen?
P450
what is the toxic acetaminophen metabolite?
NAPQI (N-acetyl-p-benzo-quinone imine)
what is the recommended daily maximum of acetaminophen by the FDA? by McNeil Consumer Healthcare (ppl that make Tylenol)?
FDA - 4000 mg/day
McNeil Consumer Healthcare - 3000 mg/day
what is the daily maximum amount of acetaminophen that patients with confirmed or suspected liver disease can take?
2000 mg/day
effects of opioids on mu and kappa receptors
- analgesia (mu >kappa)
- respiratory depression
- sedation
other effects of opioid on mu receptor
- euphoria
- dependence
- constipation
other effects opioids have on kappa receptors
dysphoria/psychomimetic
codeine, hydrocodone, and oxycodone are what type of agonists?
semi-synthetic opiate receptor agonists
codeine, hydrocodone, and oxycodone differ in what?
potency
rank potency of codeine, hydrocodone, and oxycodone
oxy > hydro > codeine
codeine, hydrocodone, and oxycodone have synergistic effect when combined with what?
acetaminophen
codeine, hydrocodone, and oxycodone combined with acetaminophen reduces what?
amount of opioid required for analgesis
what dictates dose/frequency when codeine, hydrocodone, and oxycodone in combo with acetaminophen?
acetaminophen
synthetic oral opiates must be converted into what?
active metabolites
how are synthetic oral opiates converted to active metabolites?
by cytochrome P450 CYP2D6
active metabolite of codeine
morphine (effect entirely from metabolite)
active metabolite of hydrocodone
hydromorphone (effect from parent drug and metabolite)
active metabolite of oxycodone
oxymorphone (effect almost entirely from parent drug)
what percent of caucasians are cytochrome p450 CYP2D6 deficient?
4-10%
pentazocine has analgesic effect on which opioid receptor?
kappa
pentazocine has antagonistic effect on which opioid receptor?
mu
how does tramadol havea central dual mechanism of action?
- weak binding at mu
2. inhibit incoming nociceptive impulses
tramadol has proven efficacy for what?
chronic pain
tramadol is no more effective than what?
codeine-acetaminophen combo
dentoalveolar surgery causes acute, post-operative mild-moderate pain lasting how long?
3-5 days
why give pre-operative analgesics prior to surgery?
inhibits prostaglandin synthesis therefore lessening niciception generated during procedure will reduce overall postop analgesic requirement
why give pre-operative local anesthetic before surgery?
- blockage of nociceptive input to CNS
- decreases central hyperexcitability
- less pain and analgesic intake at 4h and 48hr
- easier to maintain pain free state
T/F: non-opioids analgesics have superior efficacy than opioids for post-op dental pain relief
true
what is the go to for non-opioid analgesic?
ibuprofen
why is ibuprofen the go to NSAID?
- unsurpassed efficacy
- low side effect profile
- low cost
what is the only option when NSAID is contraindicated?
tylenol
NSAIDs have what type of effect?
ceiling effect so higher doses needed to achieve anti-inflammatory effects
why is non-narcotic analgesics prescribed around the clock on a fixed-dose schedule regardless of pain severity?
stable drug levels are attained
dosage of ibuprofen
600 mg q6h
maximum/day for ibuprofen
3200 mg
dosage of acetaminophen
650 mg q6h or 500 mg q6h
maximum/day for acetaminophen for healthy pt
3000 mg
maximum/day for acetaminophen for pt with liver issues
2000 mg
when are opioids indicated when managing moderate-severe pain?
for “breakthrough pain” if non-opioid regimen is OPTIMIZED
codiene + acetaminophen dosages
tylenol 2 = 15
tylenol 3 = 30
tylenol 4 = 60
norco
hydrocodone and acetaminophen
dosage of norco
5/325
percocet
oxycodone and acetaminophen
dosage of percocet
5/325
stepped approach to managing acute postoperative pain
- ibuprofen 600 mg q6h and acetaminophen 650 mg q6h
2. norco 5/325 1 tab q6h prn OR percocet 5/325 1 tab q6h PRN
maximum number of opioids prescribed for adults
7 days
maximum number of opioids prescribed for minors
5 days
opioids can’t be prescribed if dosing is greater than what?
> 30mg morphine equivalent dose (MED) over prescribed period
when is it best to treat pregnant patients?
2nd trimester
can pregnant patients have lidocaine?
yes
T/F: pregnant patients can be given NSAIDs to manage pain
FALSE! no NSAIDs
what can be given to pregnant patients in pain?
Tylenol and narcotic with OB approval
