Analgesics

Question 1

principles of pain therapy (pre-opioid crisis)

Answer 1

give scheduled, verify effectiveness
allow for dose titration
provide long acting analgesics around the clock or short-acting analgesics PRN for breakthrough pain (severe pain)
NOT 1-2 tabs without indicating when to use 2 vs 1

Question 2

non-opioids

Answer 2

NSAIDs and acetaminophen
if 1 class fails, try another

Question 3

opiates

Answer 3

codeine and morphine

natural agents from opium

Question 4

adjuvants

Answer 4

anticonvulsants, TCAs, SSRIs and SNRIs

Question 5

opioids

Answer 5

Tramadol, Fentanyl, Oxycodone, Methadone, etc

modifications of natural opiates (synthetics)

Question 6

NSAID combo’s

Answer 6

dual MOAs work in synergy

efficacy > sum of individual components

Question 7

Acetaminophen MOA

Answer 7

inhibits both COX isoenz’s
COX inhibition may be more pronounced in brain
inhibits hypothalamic heat-regulating center
thus explaining its antipyretic effect

Question 8

Acetaminophen Toxicity

Answer 8

at high dose: hydroxylation –> rearrangement –> reactive radical formation –> reacts with proteins and nucleic acids in the liver
glutathione in liver usually neutralizes this
toxicity based on amount of ingestion/plasma [] and time from ingestion

Question 9

acetaminophen adjustment for renal impairment

Answer 9

metabolites accumulate
CrCl 10-50: administer 16 hrs
CrCl < 10: administer q 8 hrs

Question 10

acetaminophen and ADHD risk

Answer 10

114,744 kids between 99’-09’
long term acetaminophen in preg had 2-fold inc risk
use for < 8 days during preg had dec risk

Question 11

opioid vs non-opioid for extremity pain

Answer 11

pain scores are relatively the same when combo’ing acetaminophen + ibuprofen compared to acetaminophen + opioid

Question 12

opioid receptors

Answer 12

u (mu) - classical analgesic receptor

basis of mixed agonist-antagonist agents

Question 13

endorphins

Answer 13

derived from small endogenous peptide hor’s

accounts for variability of response to pain

Question 14

other opiate/opioid SE’s

Answer 14

anticipate and prophylax for dec GI peristalsis

tolerance doesn’t develop to these effects

Question 15

Tramadol

Answer 15

now a controlled substance so less abuse potential, reclassified in 2014 (Class III)

Question 16

codeine

Answer 16

metabolized by CYP2D6 to morphine
CYP2D6 inhibitors dec its effect  
10% of pop lacks this enz  
Tylenol with codeine is C-III
Guaifenesin with codeine is C-V

Question 17

morphine

Answer 17

parenteral - to -oral dose ration of 1:3

Question 18

hydromorphone

Answer 18

alcohol destroyed time-release mech –> overdose

no active opioid metabolites

Question 19

oxycodone

Answer 19

metabolized by CYP2D6 to oxymorphone (also active)

useful in pt’s with this enz def or on inhibitors ; also useful in non-responders to codeine and hydrocodone

Question 20

CYP2D6 inhibitor meds

Answer 20

antiemetic phenothiazines, haloperidol, fluoxetine, paroxetine

Question 21

Meperidine

Answer 21

lipophilic, more rapid onset, short duration (2-3 hrs)
metab to active metab noremeperidine (neurotoxic)
long-metabolite t1/2 life
useful in controlling post-anesthesia shivering

Question 22

methadone

Answer 22

unique pharm-racemix mix of I and d isomers
I isomer –> opioid activity
d isomer –> NMDA antagonist and NE/5-HT reuptake inhibitor

Question 23

duragesic cautions

Answer 23

not usually used in opiate naive pt’s
monitor RR for first 24 hrs
replace q 72 hrs (don’t just add additional patches, look for multiple patches when admitting out-pt’s!)

Question 24

CDC opioid prescribing guidelines

Answer 24

nonpharm therapy and non-opioid therapy are preferred for chronic pain
clinicians should prescribe IR opioids instead of ER
for acute pain, use the lowest effective dose of IR opioids for 3-7 days

Question 25

CDC opioids prescribing guidelines cont

Answer 25

rx lowest effective dose. reassess risks and benefits when doses inc to > 50 morphine MME/day and avoid incing to > 90 MME without careful justification
eval benefits and harms within 1-4 weeks and again every 3 mo or more freq

Question 26

CDC opioids prescribing guidelines cont again

Answer 26

incorporate strategies to mitigate risk: offering naloxone
monitor a pt’s controlled substance abuse
use UDS before starting opioid therapy and check at least annually
avoid rx opioids and bozo’s concurrently
offer or arrange evidence based tx for pt’s with opioid use dx

Question 27

injectable Acetaminophen (Afirmed)

Answer 27

1000 mg/100 mL (post op x 4 doses, $$$$)
adults/adolescents > 50 kg: 1000 mg q6h, max 4 g/d
adults/adolescents < 50 kg: 15 mg/kg q6h, or 12.5 mg/kg q4h; max 75 mg/kg/d