Pain Meds Flashcards
what medication would you not want to take in with an OTC pain killer?
Tylenol (because it’s commonly combined w/ other meds for OTC painkillers & cold meds)
T/F, acetaminophen is an anti-inflammatory
False
MOA of acetaminophen
unknown: it’s an analgesic & antipyretic - raises pain threshold
(Centrally acting, may block cytokines in the dorsal horn, blocks PG release in CNS)
indications of acetaminophen
- temporary relief of minor aches/pains
- fever reduction
what is acetaminophen first line for?
treatment of knee, hip osteoarthritis per ACR
Regular strength tylenol dose
325 – 650 mg q4 – 6h prn pain
Extra strength tylenol dose
1000 mg q6h prn pain
max daily dose of tylenol (adult)
4 g/day
max daily dose of tylenol (peds)
5 doses (50-75 mg/kg)/day (pts 12 & under)
why do you not want to exceed 3 alcoholic beverages per day when taking tylenol?
LIVER WARNING!!!
which tx is more effective in knee osteoarthritis, acetaminophen or hyaluronic acid inj?
Most effective: hyaluronic acid injections
Least effective: acetaminophen
what are nociceptors?
Primary sensory neurons that respond to noxious stimuli
at what age should parents talk to a PCP prior to administering tylenol to their child?
2 yrs/2 mos…can’t remember
what is the 2 step strategy for WHO Pain Treatment Peds 2012
Mild pain:
Acetaminophen or ibuprofen
< 3 mos of age, acetaminophen
Moderate to severe pain:
Opioids
which opiod is the DOC for peds w/ mod-sev pain?
Morphine is drug of choice (DOC)
why do we want to avoid giving codeine to peds?
pharmacogenomic variability (codeine is a prodrug of morphine, metabolized by 2D6)
why do we want to avoid tramadol in peds?
lack of evidence
what was the WHO Pain Ladder Adults 1986 originally created for?
CA pts
what’s another name for acetaminophen/tylenol?
paracetamol, APAP
what is APAP/acetaminophen metabolized by?
NAPQI (N-acetyl-p-benzo-quinone imine)
when does APAP/acetaminophen reach Cmax?
30 – 60 min
what med is the leading cause of acute liver failure in the US
acetaminophen
48% of acetaminophen-related cases (131 of 275) associated with accidental overdose
what were the majority of acetaminophen-associated OD cases from?
intentional overdose (70%)
FDA limits Rx combo meds to ___ mg acetaminophen
325 mg
what is the boxed warning for acetaminophen?
severe liver injury
allergic rxn
alcoholics
pts taking P450, 2E1 inducers
pts fasting, malnourished, dehydrated
pt’s w/ a viral illness
are at a higher risk of what, when taking APAP?
hepatoxicity
what doses of acetaminophen induce hepatoxicity?
10-15 g
>20 g can be fatal
what does TK stand for?
think PK
toxicity kinetics
vs pharmokinetics
how long after tylenol OD will serum concentrations peak?
4 hrs
what organs are affected by APAP toxicity? (5)
Liver (cell damage) Renal (ATN) Heart Pancreas CNS
list the early sx of APAP toxicity (5)
Nausea, Vomiting, AMS (maybe), metabolic acidosis, increased PT/INR
MOA of NSAIDs
Inhibit cyclooxygenase enzymes (COX)
what are COX?
Prostaglandin synthase enzymes
what is the difference between COX-1 & COX-2?
COX-1: Physiologic, Constitutive (found in nearly all cells at constant levels)
COX-2: Pathologic, Inducible (released in response to cell mediators; pyretic, pain, inflammatory actions)
why is there a risk of renal ischemia w/ chronic NSAID use in pts w/ renal insufficiency, CHF or cirrhosis?
PGs help maintain renal blood flow in compromised kidneys & NSAIDs inhibit PG synthase enzymes
why should pts avoid NSAIDs in their 3rd trimester?
PGs induce uterine contractions during labor; may cause premature closure of PDA (Patent ductus arteriosus)
what med is used to help prevent premature labor?
Indomethacin
which is better to be selective for, COX-1 or COX-2?
COX-2
what pain relievers are best for runners (during/after)?
APAP (because NSAIDs can further damage kidneys)
name 3 indications for NSAIDs
- Acute/chronic pain (form any cause, caution w/ long-term use)
- Cancer pain
- Anti-inflammatory
name some common ADRs of NSAIDs
Nausea, dyspepsia, anorexia, abdominal pain, flatulence, diarrhea
how can you reduce GI SEs?
take w/ food/milk
enteric-coated products should not be taken with milk or antacids
what’s the big risk w/ NSAIDs?
GI bleed: particulary w/ chronic use, elderly, CVD, h/o peptic ulcer or GI bleed
(ulcer, GI perf & death more rare)
For chronic NSAID use, PPIs (-prazole) reduced risk of gastric & duodenal ulcers AND ___ & ___
GI bleed & dyspeptic sx
For chronic NSAID use, double-dose H2RAs (-tidine) reduced gastric & duodenal ulcers AND ___
abd pain
what is Yosprala (aspirin/omeprazole) used for?
patients who need ASA for CV risk, but are at risk for ulcers
what is another concern of NSAID use? (NOT GI/kidney)
HF
what is misoprostol?
Synthetic prostaglandin E1 analog
MOA for misoprostol
Inhibits gastric acid secretion
Protects GI mucosa, reduces incidence of gastric & duodenal ulcers
misoprostol ADRs
Nausea, DIARRHEA, Abdominal pain
worse w/ higher doses, ~25% pts experience SEs
warnings for misoprostol
abortifacient (induction of laobr/uterine rupture after 8th wk of pregnancy
teratrogenic (preg cat X; deformities if used during 1st trimester)
what test to you need to run before prescribing misoprostol to a female pt?
pregnancy test (need to counsel on abortive effect, document!, pt cannot share med w/ others)
what risk is associated w/ COX-2 inhibitors?
CV (MI)
all NSAIDs can raise BP
which NSAID is safest for CVE?
naproxen
what is aspirin (acetylsalicylic acid)
Nonselective COX inhibitor
suicide inhibitor - irreversible
what is the max daily dose of ASA?
4 g/day
ASA MOA
Anti-platelet
Analgesic, anti-inflammatory
Anticancer?
daily max dose of ibuprofen?
3200 mg/day (Rx)
2400 mg/day (OTC)
daily max dose of naproxen?
1500 mg/day
which NSAID would you especially not want to Rx if pt has an ASA allergy?
naproxen
what is first-line for gout flares?
indomethacin
(take for up to a wk)
can also use naproxen
3 indications for indomethacin
Gout flares
Close PDA in neonates
Can be used for premature labor (< 48 hrs)
Which med is a “true COX-2 inhibitor”?
celecoxib
Stage 1 APAP toxicity
No liver injury Asymptomatic or Early signs/symptoms Normal LFTs Nausea, vomiting, diaphoresis, pallor, malaise
Stage 2 APAP toxicity
Liver injury 24 - 36 hours AST elevated (may be > 1000) RUQ pain, hepatomegaly Possible nephrotoxicity Increased PT, bilirubin, sCr, BUN Proteinuria, hematuria, casts
Stage 3 APAP toxicity
Maximum liver injury 72 to 96 hours Hepatic failure Encephalopathy Coma Hemorrhage Nausea/vomiting may return High ammonia level AST/ALT elevated > 10,000 IU/L Abnormal: PT, creatinine, Glucose, pH, Bilirubin, lactate Fatality (Usually 3 – 5 days after OD, Multiorgan failure, Hemorrhage, ARDS, Sepsis, Cerebral edema)
Stage 4 APAP toxicity
Recovery
Hepatic regeneration
Several days to weeks
What is used to predict the likelihood of tylenol toxicity & determine the need for antidote?
Rumack-Matthew Nomogram
What is the antidote for tylenol toxicity?
NAC (N-acetylcysteine): admin w/in 8 hrs of OD, use w/ possible/probable risk of hepatotoxicity, preg cat B
MOA of NAC
Prevents hepatic injury by limiting formation of NAPQI
NAC dosage
IV/PO (fewer ADR PO)
IV anaphylaxis possible: rash, urticaria, pruritus, flushing, N/V, bronchospasm, potentially fatal - antihistamines, steroids, beta agonist, epi
