Pain Flashcards
Nociceptive pain
Pain that occurs as a result of tissue damage/trauma/injury
Pathophysiologic pain
Pain that occurs from damage or malfunction of the nervous system (neuropathic pain)
APAP max daily dose
4000 mg daily
APAP pediatric dose
10-15 mg/kg q4-6 hours, max 5 doses per day
What does APAP have a boxed warning for?
hepatotoxicity (associated with >4g per day dosing and/or use of multiple APAP-containing products)
What is the antidote to APAP overdose?
N-acetylcysteine (PO or IV)
What nomogram is used to determine the need for NAC treatment/severity of APAP overdose?
The Rumack-Matthey nomogram
What is the MOA of NSAIDs?
Inhibition of COX enzymes –> decreased prostaglandin production –> decreased inflammation/pain
What does blocking COX-1 result in?
Decreased formation of TxA2 –> decreased platelet activation and aggregation
What boxed warnings do all NSAIDs have (not including ASA)?
GI risk: increased risk of GI bleeds/ulceration
CV risk: increased risk of MI and stroke
NSAID use is CI after CABG surgery
What are SE for all NSAIDs?
Decreased renal clearance; caution in renal failure
Increased BP
Premature closure of ductus arteriosus - avoid in 3rd trimester of pregnancy
GI upset - can be reduced with EC formulations and by taking with food
Photosensitivity
Edema
What 2 drugs can be used to close a ductus arteriosus after birth?
IV indomethacin or ibuprofen
Adult ibuprofen dosing
OTC: 200-400 mg q4-6h; max 1.2 g/day
Rx: 400-800 mg q6-8h; max 3.2 g/day
Peds ibuprofen dosing
5-10 mg/kg/dose q6-8h
Max 40 mg/kg/day
What is a unique SE of indomethacin?
High risk for CNS SE - avoid in psych conditions
What is the dosing frequency for naproxen?
q8-12h
What are unique warnings for ketorolac?
Increased bleeding
Acute renal failure
Liver failure
Anaphylaxis
What is the max duration of therapy for ketorolac?
5 days (total for all formulations used)
At what dose must ketorolac be given IM?
60 mg dose
When must a ketorolac dose be reduced?
if pt >65 yo
Which NSAIDs are COX-2 selective?
Celecoxib (Highest selectivity)
Diclofenac
Meloxicam
Etodolac
Nabumetone
Celecoxib should not be used in pts with a _________ allergy.
Sulfonamide
What is the max daily dose for voltaren?
32 g per day
What is the cardioprotective ASA dosing?
81-162 mg qd
What is the analgesic dosing for ASA?
325-650 mg q4-6h
What population should salicylates be avoided in?
Children and teens (esp with viral illness)
DDIs for NSAIDs
Can increase lithium levels
Can increase methotrexate levels
MOA for opioids
Mu receptor agonists
Boxed warnings for opioids
1) Addiction, abuse, and misuse can lead to OD and death
2) Resp depression
3) Increased risk of death when used with CNS depressants, BZDs, or alcohol
4) Accidental OD/exposure in peds
5) Do not crush/dissolve/chew ER formulation - can result in OD
6) Life-threatening withdrawal in neonates with prolonged use in pregnancy
SE for opioids
Constipation, N/V, somnolence, dizziness, lightheadedness, resp depression, pruritus
What enzyme is codeine metabolized via?
CYP2D6
What populations can codeine not be used in?
Nursing mothers, all children <12 yo, children <18 yo post-tonsillectomy/adenoidectomy
Active metabolite of codeine?
Morphine
What enzyme is fentanyl metabolized via?
CYP3A4
Who is eligible to be converted to a fentanyl patch?
Pts who have been using equivalent to at least 60 mg/day morphine for at least 7 days
Can you cover a fentanyl patch?
Yes but only with Bioclusive or Tegaderm
How should fentanyl patches be disposed of?
Flushed down toilet
How often are fentanyl patches changed?
q72h
What enzyme is hydrocodone metabolized via?
CYP3A4
What med error is common with hydromorphone?
High potency (HP) injection (10 mg/mL) should only be given to opioid tolerant pts; often confused with dilaudid (1 mg/mL)
What warnings/SE are unique for methadone?
QT prolongation
Risk of serotonin syndrome with MAOi and serotonergic agents
Blocks reuptake of NE
Can decrease testosterone –> sexual dysfunction
What enzyme is methadone metabolized via?
CYP3A4
What warnings are unique for meperidine?
Renal impairment and elderly at increased risk for CNS toxicity (seizures)
Increases risk of serotonin syndrome
Meperidine active metabolite
Normeperidine
What SE is common with morphine?
Pruritus (histamine induced - treat w/ benadryl)
What enzyme is oxycodone metabolized via?
CYP3A4
Special admin instructions for oxymorphone
Take on empty stomach
When converting between opioids, how much should the daily dose be reduced by?
25% (only if the exam asks to reduce)
How should most opioids be taken?
With food
First line for OIC?
bisacodyl +/- stool softener
MAO for PAMORAs
Peripherally-acting mu-opioid antagonists: blocks opioid receptors in the gut to decrease constipation without affecting analgesia
Warnings/SE for PAMORAs
GI obstruction/perforation, abdominal pain, flatulence
Examples of PAMORAs
Methylnaltrexone (Relistor)
Naloxegol (Movantik)
Naldemedine (Symproic)
What enzyme is tramadol metabolized via?
CYP2D6 (and some 3A4)
What warnings do tramadol and tapantadol both have?
Increased seizure risk
Risk of serotonin syndrome
CI within 14 days of MAOi
How often are buprenorphine patches changed?
Weekly
Warnings for buprenorphine
Can prolong QTc
CNS depression
When must pregabalin and gabapentin be dose adjusted?
CrCl <60
SE for gabapentin
Dizziness, somnolence, peripheral edema, weight gain
Counseling points for ER gabapentin (Horizant)
Take with food
Not interchangable with IR
SE for pregabalin
Dizziness, somnolence, peripheral edema, weight gain, mild anxiolytic
What is carbamazepine approved for?
Trigeminal neuralgia (only FDA approved agent for this indication)
What is milnacipran (Savella)?
An SNRI indicated only for fibromyalgia
SE for muscle relaxants
Sedation, dizziness, confusion, asthenia
What population is at risk for baclofen OD
Elderly
SE/warnings for cyclobenzaprine
Dry mouth
Serotoneric
What enzyme is tizanidine metabolized via?
CYP1A2
SE for tizanidine
Hypotension
Dry mouth
(alpha 2 agonist)
What enzyme is carisoprodol metabolized via?
CYP2C19
What is dantrolene primarily used for?
Malignant hyperthermia
How many lidocaine patches can be worn at once and for how long?
Up to 3 patches worn for up to 12 hours/day
What drug(s) are recommended for the treatment of menstrual associated migraines w/ aura?
Progestin only OC (avoid stroke risk of estrogen)
Diagnosis criteria for migraines
1) At least 5 attacks
2) HA lasting 4-72hrs and occur sporadically
3) >/=2 of the following: unilateral location, pulsating, mod-severe pain, aggravated by physical activity
4) N/V, photophobia, and/or phonophobia occurs during HA
Supplements used for migraine
Caffeine, butterbur, feverfew, Mg, riboflavin, peppermint (topical)
Triptan MOA
5-HT1 agonists
Cause vasoconstriction of the cranial blood vessels, inhibit neuropeptide release, and decrease pain transmission
What drugs are first line for acute migraine treatment?
Triptans
Examples of triptans
Sumatriptan (Imitrex, Onzetra)
Rizatriptan (Maxalt)
Zolmitriptan (Zomig)
CI for triptans
1) CVD
2) Uncontrolled HTN
3) Ischemic heart disease
4) Use within 24 hrs of another triptan or ergot
5) MAOi (suma, riz, and zolm)
Warnings/SE for triptans
Increased BP
Serotonin syndrome
Paresthesia
“Triptan sensations” = pressure/heaviness in neck or chest region; dissipates after administration
When can a triptan dose be repeated after?
2 hours (as long as does not exceed max daily dose)
Max daily dose for sumatriptan = 200 mg
How many sprays do triptan nasal sprays contain?
1 dose - do not prime
Which triptan is approved for children under 12 years old?
Rizatriptan (approved for ages 6+)
Preferred site for sumatripan injections
Lateral thigh or upper arm (subq)
Ergotamine MAO
Nonselective serotonin agonist that causes cerebral vasoconstriction
Usually 2nd line if triptan ineffective
What enzyme are ergots metabolized via?
CYP3A4
CI for ergots
Administration with CYP3A4 inhibitors –> serious and life threatening peripheral ischemia
Pregnancy
Uncontrolled HTN
Ischemic heart disease
Use within 24 hours of triptans or other ergots
Examples of ergots
Dihydroergotamine (Migranal, DHE 45)
Ergotamine + caffeine (Cafergot)
Warnings for ergots
CV events
Cerebrovascular events
DDIs
Do you have to prime DHE sprays?
Yes
Examples of CGRP receptor antagonists
Rimegepant (Nurtec) - prevent and treat
Ubrogepant (Ubrelvy) - treat acute only
Aimovig - prevent
Emgality - prevent
MAO of lasmiditan (Reyvow)
Selective serotonin agonist - targets 5-HT1F receptor
Does not cause vasoconstriction –> not CI with CVD
What is the risk of not tapering off butalbital therapy?
Worsening HA, tremors, risk for delirium and seizures
When should migraine prophylaxis be considered?
Use of acute treatments >2 days/week or >3x per month
Decreased QoL
Acute treatments are CI
What antihypertensives can be used for migraine prophylaxis?
BB (propranolol preferred)
What antiepileptics can be used for migraine prophylaxis?
Topiramate (can also cause weight loss)
Valproic acid/divalproex
What antidepressants can be used for migraine prophylaxis?
TCAs (amitriptyline preferred)
Venlafaxine
To reduce risk of rebound HA, acute treatment should be limited to how many times/week
2-3 times per week
RF for gout
Male, obesity, EtOH, HTN, CKD, lead, older age
Meds that can increase uric acid
ASA (low doses)
Calcineurin inhibitors (tacrolimus, cyclosporine)
Diuretics
Niacin
Pyrazinamide
Some chemo and pancreatic enzyme products
What foods can worsen/cause gout?
Organ meats
High fructose corn syrup
Alcohol
Sugar (fruit juice, sweet drinks, desserts)
Salt
Beef, lamb, pork, sardines, shellfish
What drugs are used for acute gout treatment?
Colchicine
Steroids
NSAIDs
What drugs are used for chronic gout prevention?
Xanthine Oxidase Inhibitor (Allopurinol or febuxostat)
Can add on probenecid or lesinurad if needed
Warnings/SE for colchicine
Myelosuppression
Increased risk for myopathy
N/D
Neuropathy
Colchicine treatment dosing
1.2 mg PO then 0.6 mg in 1 hr (within 36 hours on onset)
Hold prophylaxis dose for 12 hrs after treatment dose
Colchicine prophylaxis dosing
0.6 mg qd or bid
Colchicine DDIs
CYP3A4 or P-gp inhibitors
Pts at high risk for allopurinol hypersensitivity rxn should be screened for what gene?
HLA-B*5801 allele
MOA of xanthine oxidase inhibitors
Blocking XO stops production of uric acid
MOA of probenecid
Inhibits reabsorption of UA in the proximal tubule
Can also be used to increase beta-lactam levels by decreasing clearance
Counseling points for allopurinol
Skin rxns with (+) allele
SE: rash, acute gout flare, N/D, increased LFTs
When first starting, should be given with colchicine or NSAID for first 3-6 months
Take after meal to decrease N/D
Counseling points for febuxostat
Can be used if allopurinol allergy
Increased risk of CV death, hepatotoxicity, some risk for skin reactions
When first starting, should be given with colchicine or NSAID for first 3-6 months
Counseling points for pegloticase
Only for severe gout (IV)
Box warning for anaphylaxis: must premedicate with benadryl and steroids
CI with G6PD deficiency
Do not use with XOI or probenecid (increased risk of anaphylaxis)
DDI for XOIs
Avoid with mercaptopurine and azathioprine
Separate from antacids
Counseling points for rasburicase (Elitek)
Used in the treatment of tumor lysis syndrone
CI with G6PD deficiency - d/c if signs of hemolysis
