58. Pain Flashcards
Acetaminophen effects
Reduces pain and fever
does NOT provide anti-inflammatory effects
MOA for acetaminophen is not well defined but is thought to involve ____
inhibition of PG synthesis in the CNS
acetaminophen rectal suppository brand name
FeverAll
acetaminophen IV injection brand name
Ofirmev
APAP/hydrocodone brand name
Norco
acetaminophen/codeine brand name
Tylenol #3
acetaminophen/caffeine brand name
Excedrin Tension Headache
acetaminophen/aspirin/caffeine brand name
Excedrin Extra Strength, Excedrin Migraine
acetaminophen/caffeine/pyrilamine brand name
Midol Complete
acetaminophen max dosing for adults
<4g/day
acetaminophen pediatric dosing (<12 yo)
10-15mg/kg q4-6h
acetaminophen infant and children’s suspension concentration
160mg/5mL
Boxed warnings for acetaminophen
hepatotoxicity, a/w >4g/day or use of multiple APAP-containing products
Antidote for acetaminophen overdose
N-acetylcysteine (NAC, Acetadote) - glutathione precursor (increases glutathione), administered IV or PO
_____ nomogram uses the serum acetaminophen level and the time since ingestion to determine whether hepatotoxicity is likely (and the need for NAC)
Rumack-Matthew
Non-aspirin NSAID boxed warnings
GI risk - bleeding/ulceration
CV risk - MI/stroke
Contraindicated in CABG surgery (antiplatelet therapy (commonly aspirin) is recommended after CABG surgery)
Aspirin MOA
irreversible COX-1 and 2 inhibitor
Side effects of all NSAIDs
Use cautiously or avoid in renal failure
Increased BP - avoid in uncontrolled HTN
Do NOT use in third trimester of pregnancy (can cause premature closure of ductus arteriosus)
Nausea - take with food or use EC formulation
Photosensitivity
What is the concern of use of NSAIDs in pregnant patients?
Do NOT use NSAIDs in 3rd trimester of pregnancy, NSAIDs can prematurely close ductus arteriosus
After birth, the ductus arteriosus should close on its own. In some cases, it remains patent (open) and ___ can be used within 14 days after birth to close it.
IV NSAIDs (indomethacin, ibuprofen)
Which non-aspirin NSAIDs are non-selective?
Ibuprofen (Advil, Caldolor, Motrin IB)
Indomethacin (Indocin)
Naproxen (Aleve)
Ketorolac (Toradol, Acular Sprix)
Others: piroxicam (Feldene), sulindac
Which non-aspirin NSAIDs have increased COX-2 selectivity?
CElecoxib (Celebrex)
Diclofenac (Voltaren)
Meloxicam (Mobic)
Others: Etodolac, Nabumetone
Ibuprofen OTC max duration of self-treatment
<10 days
Why should indomethacin (Indocin) be avoided in psych conditions?
High risk for CNS side effects
Why do prescribers and patients sometimes prefer naproxen?
Dosed BID (less frequent dosing)
Ketorolac max combined duration IV/IM and PO/nasal in adults
5 days
Ketorolac warnings
Acute renal failure and liver failure
Important notes for ketorolac nasal spray
Prime 5 times before use (no additional priming needed if additional doses are used, discard 24 hrs after opening)
Celecoxib (Celebrex) contraindications
Sulfonamide allergy
Pt has a sulfa allergy. Which NSAID should be avoided?
Celecoxib
Which non-aspirin NSAID has highest COX-2 selectivity?
Celecoxib
Diclofenac/misoprostol (Arthrotec) boxed warnings
Avoid in females of childbearing potential
____ is used to replace gut-protective prostaglandins to decrease GI risk when using diclofenac.
Note: can increase uterine contractions (which can terminate pregnancy) and causes cramping and diarrhea
Misoprostol
Cardioprotection dosing of aspirin
81-162 mg once daily
Why should aspirin be avoided in children and teenagers with any viral infection?
Potential risk of Reye’s syndrome
What brand names are the EC/buffered aspirin formulations?
Ascriptin, Bufferin, Ecotrin
Which brand names of aspirin is ER capsule and Rx only?
Durlaza
Salicylate overdose can cause ___
tinnitus
___ is a popular OTC topical found in BenGay, IcyHot, Salonpas, and Thera-Gesic
Methyl salicylate
Example of a non-acetylated salicylate
Magnesium salicylate (Doan’s Extra Strength)
Multiple NSAIDs should not be used together except the addition of low dose aspirin for cardioprotection when indicated. If using aspirin for cardioprotection and ibuprofen for pain, how should you separate doses?
Aspirin 1 hr before or 8 hrs after ibuprofen
NSAIDs can increase levels of ___ and ___
lithium and methotrexate
Opioids MOA
Mu receptor agonists (produce pain relief but also cause euphoria and respiratory depression)
Opioids Boxed warnings
Addiction, abuse, misuse»_space; overdose, death
Respiratory depression (can be fatal)
Concurrent use with BZD or other CNS depressants can increase risk of death
Do not consume alcohol with ER formulations, increased drug plasma levels»_space; fatal overdose
Accidental ingestion/exposure in children can be fatal, never share medication (including patches)
Crushing, dissolving, or chewing ER products can cause delivery of potentially fatal dose
Avoid prolonged use in pregnancy (neonatal opioid withdrawal)
Define physiological adaptation (physical dependence)
Physical withdrawal symptoms when opioid is stopped or dose is late/missed
S/sx: anxiety, tachycardia, shakiness, SOB
Note: not the same as addiction
Side effects of opioids
Constipation, N/V (esp with acute, high-dose use), somnolence, dizziness/lightheadedness, risk of respiratory depression, pruritus common (esp in opioid-naive pts, can premedicate with diphenhydramine)
Drug schedule for codeine vs codeine/acetaminophen vs oral solution combo products (cough syrups)
Codeine = CII
Tylenol #3, #4 = CIII
Cough syrups = CV
Fentanyl patch dosing frequency
1 patch Q72H (can be Q48H)
Which brand name of fentanyl comes in a lollipop formulation?
Actiq (oral transmucosal lozenge on a stick)
Fentanyl is available in different strengths ranging from ____
12-100 mcg/hr
Fentanyl is not used in opioid naive patient. What makes a pt a candidate to switch to fentanyl patches?
Using equivalent to morphine 60mg/day for at least 7 days
Hydrocodone IR + acetaminophen combo products have the ___ mg of acetaminophen regardless of hydrocodone strength.
325mg
Which opioids are CYP3A4 substrates (use with 3A4 inhibitors may cause fatal overdose)?
Hydrocodone, fentanyl, methadone, and oxycodone
Hydromorphone (Dilaudid) initial opioid-naive dosing for oral and IV
PO: 2-4mg q4-6h PRN
IV: 0.2-1mg Q2-3h PRN
Boxed warning for hydromorphone (Dilaudid)
Risk of medication error with high potency injection (use in opioid-tolerant pts only)
Note: potent opioid, higher risk for overdose
Boxed warning for methadone
QT prolongation
What is the concern of methadone dosing?
Variable half-life, hard to dose safely
What is the concern of methadone use in some male pts?
May decrease testosterone and contribute to sexual dysfunction
Warnings for meperidine (Demerol)
Renal impairment/elderly at risk for CNS toxicity - avoid with or within 2 weeks of MAOi
Increased risk of serotonin syndrome with other serotonergic drugs
Note: no longer recommended as an analgesic
Things to note regarding normeperidine (metabolite of meperidine)
renally cleared and can accumulate and cause CNS toxicity including seizures
Which brand names of morphine are injections?
Duramorph, infumorph
Morphine side effects
Pruritus, dry mouth, hyperhidrosis
Diphenhydramine can be given to block histamine-induced pruritus
Oxycodone IR, CR, ER brand names
IR = Roxicodone
CR = OxyContin
ER = Xtampza ER
Oxycodone/acetaminophen brand name
Endocet, Percocet
All oral opioids should be taken with food to lessen nausea except one. Which opioid is recommended to take on an empty stomach?
Oxymorphone
Morphine, Hydromorphone, Oxycodone conversion for IV/IM and PO
Morphine IV/IM 10mg = Hydromorphone IV/IM 1.5mg
Morphine PO 30mg = Hydromorphone PO 7.5mg = Oxycodone PO 20mg
T/F: opioids are typically first-line for chronic pain treatment d/t strength and efficacy
False
Opioids that cross-react in opioid allergy
Drugs that have cod or morph (norph)
Codeine, hydrocodone, oxycodone, morphine, hydromorphone, oxymorphone, burprenorphine, heroin (diacetyl-morphine)
Opioid-induced respiratory depression risk factors
Hx of previous overdose
substance use disorder
large doses (≥50mg morphine or equivalent)
Use of BZD, gabapentin, or pregabalin
Comorbid illnesses, such as respiratory or psychiatric disease
Note: Naloxone should be readily available to pts with increased risk
T/F: constipation with opioid use is transient and will lessen over time
False - most opioid side effects usually lessen over time EXCEPT constipation
What is first-line treatments for opioid-induced constipation?
Stimulant (e.g. senna, bisacodyl) or osmotic (e.g. PEG) laxatives with or without stool softeners
Bisacodyl comes as tablet (ppx) or suppository (treatment)
If laxatives are not sufficient for opioid-induced constipation, what can be used?
Peripherally-acting mu-opioid receptor antagonists (PAMORAs)
What are some examples of PAMORAs?
Methylnaltrexone (Relistor)
Naloxegol (Movantik)
PAMORA warnings and side effects
GI perforation
Abdominal pain and flatulence
Tramadol and tapentadol MOA
Mu-opioid receptor agonists and inhibitors of NE reuptake
Tramadol also inhibits reuptake of serotonin
Tramadol (Ultram) drug schedule
C-IV
Tapentadol (Nucynta) drug schedule
C-II
Warnings for centrall acting analgesics (tramadol, tapentadol)
Lower seizure threshold
Caution with other serotonergic drugs
Avoid tramadol with CYP2D6 inhibitors
S/sx of opioid overdose
Extreme sleepiness, slow or shallow breathing, fingernails or lips turning blue/purple, extremely small “pinpoint” pupils, slow heartbeat and/or BP
Naloxone is available in 2 options. What are they and what are the differences?
Narcan (nasal spray): onset is slower than injection, comes as single-use nasal pray 4mg in 1 nostril, repeat in alternating nostrils if needed
Naloxone (injection): repeat every 2-3 minutes until EMS arrives
Side effects of naloxone or nalmefene
Opioid-dependent: acute withdrawal symptoms (pain, anxiety, tachypnea, diarrhea, agitation)
Buprenorphine MOA
partial mu-opioid agonists
agonists at low doses and antagonist at higher doses (lower doses to treat pain, higher doses to treat addiction)
Naloxone MOA
Opioid antagonists
How does buprenorphine/naloxone combo drug work?
Used as alt to methadone for opioid use disorder
Buprenorphine suppresses withdrawal symptoms and naloxone helps prevent misuse
Buprenorphine patch (Butrans) application
Apply to upper outer arm, upper chest, side of chest or upper back
Change weekly
Do not use same sit for at least 3 weeks
Can only be covered with Bioclusive or Tegaderm, do not exposre to heat)
Adjuvants are commonly used in pain a/w ____
neuropath, postherpetic neuralgia (PHN), fibromyalgia and osteoarthritis (OA)
____ injection can be added to opioids in intrathecal (epidural) pain infusion pumps for pts with cancer pain when other agents are insufficient
Clonidine
Which gabapentin formulation is indicated for postherpetic neuralgia (PHN) and restless legs syndrome?
Gabapentin enacarbil (Horizant)
Side effects of gabapentin, pregabalin
Dizziness, somnolence, peripheral edema/weight gain
Others: ocular effects, ataxia, nystagmus, tremor, dry mouth, mild anxiolytic
Which adjuvant pain med for neuropathic pain is FDA-approved for treatment of trigeminal neuralgia?
Carbamazepine (Tegretol)
Which adjuvant pain med for neuropathic pain is approved for use in fibromyalgia, PHN, and neuropathic pain a/w DM and spinal cord injury?
Pregabalin (Lyrica)
Muscle relaxants used for pain
Baclofen (Lioresal)
Cyclobenzaprine (Amrix, Fexmid, Flexeril)
Tizanidine (Zanaflex)
Carisoprodol (Soma) - CIV
Methocarbamol (Robaxin)
Poor CYP___ metabolizers will have increased carisoprodol conc, while rapid metabolizers will concert to active metabolite faster (increased tox/sedation)
2C19
All muscle relaxant side effects
sedation, dizziness, confusion, asthenia (muscle weakness)
Tizanidine (Zanaflex) side effects
Hypotension, dry mouth, increased LFTS
Cyclobenzaprine (Amrix, Fexmid) side effects
Dry mouth
Serotonergic - do not combine with other serotonergic agents
Lidocaine (Lidoderm) dosing
Apply to painful area 1-3 patches/day and wear up to 12 hrs/day
Do not apply more than 3 patches at one time
Can cut into smaller pieces (before removing backing)
Which topical adjuvants for pain is approved for PHN (shingles) pain?
Lidocaine
Which medications are approved for fibromyalgia?
Pregabalin (Lyrica)
Duloxetine (Cymbalta)
Which morphine product can be opened and sprinkled on apple sauce or soft food?
Kadian (morphine ER capsules)