Opiates Flashcards
what plant is opium derived from?
poppy flower
Name 3 opiates that are strictly mu receptor agonists
codeine, oxycodone, hydrocodone
name 3 opiates that can activate both mu and kappa receptors
nalbuphine, butorphanol, buprenorphine
Name the phenanthrenes
natural: codeine, morphine, semisynthetic: hydrocodone, hydromorphone, oxycodone, oxymorphone
name the phenylpiperidines
meperidine, fentanyl
name the phenylheptylamines
methadone (+propoxyphene)
are opiates narcotics?
no - don’t refer to opiates as narcotics
if a phenanthrene isn’t effective for a pt, name 2 drugs you could switch to
meperidine, fentanyl
if fentanyl isn’t effective for the pt, name a drug you could switch to
methadone
True or false: opiates are used as backup therapy, first line depends on the type of pain
TRUE - opiates are backup therapy
according to WHO, mild pain can be treated with
non-opiate analgesics with or without adjuvant medications
according to WHO, mild to moderate pain can be treated with
weak opiate + non-opiate analgesic with or without adjuvant meds
according to WHO, moderate to severe pain can be treated with
strong opiates with our without non-opioid analgesic medication with or without adjuvant medications
NRS
numeric rating scale - should be included on scripts
what is the name of the faces scale for pain?
Wong baker faces rating scale
what are examples of nociceptive pain?
tissue injury, joints, MSK, burns, incisions
what are examples of neuropathic pain?
carpal tunnel, DM, CA, shingles
does neuropathic pain respond well to opiates?
no
where do opiates work in the brain?
site of action is the PAG and it blocks GABA. From the PAG it moves to the medulla which mediates NE and serotonin. MOR blocks Ca2+ and opens K+ channels causing hyperpolarization. Also acts at post-synaptic and K1 receptors
MOA of opiates
inhibition of painful stimuli in the substantia gelatinosa of the spinal cord, brainstem, reticular activating system, thalamus, and th elimbic system
effects of opiates
sedation, euphoria, mental clouding, respiratory depression, miosis, decreased peristaltic motility, depression of the cough reflex and orthostatic HOTN
ADR of opiates
increased esophageal reflux, N/v in the CTZ, peripheral vasodilation, increased histamine, prolongs labor, decreased urinary void reflex
which mu receptor is best known?
mu1
where are mu receptors found?
primarily supraspinal than spinal - all over: PAG, superficial dorsal horn, amygdala
what type of pain do mu receptors relieve
somatic pain more than visceral pain
ADR of mu receptor agonists
respiratory depression, euphoria, dependence, decreased GI motility, miosis
where are kappa receptors mostly located?
spinal more than suprespinal
what type of pain is relieved by kappa receptor agonists?
visceral pain
ADR of kappa receptor agonists?
sedation, miosis, dysphoria
primary location of delta receptors
spinal more than supraspinal
ADR of delta agonists
tachycardia, tachypnea, dysphoria, hallucinations, mydriasis, hypertonia
what is the “relative” of oxycodone with a longer T1/2?
oxycontin
what are opiates used for?
pain relief
are opiates susceptible to first pass effect?
yes
how are opiates metabolised?
CYP450/2D6 (genetic variability in metabolism)
how are opiates excreted?
in the urine, small amount in the feces (watch with renal impairment - may build up opiates)
what drugs will decrease opiates in the system by stimulating 3A4?
st. john’s wart, antiseizure drugs
what drugs will increase opiates in the system by inhibiting 3A4?
azoles, macrolides
what drugs will increase opiates in the system by inhibiting 2D6?
fluoxetine, paroxetine, wellbutrin, rionavir
what other drugs will increase CNS effects of opiates?
alcohol, sedatives, muscle relaxants, phenothiazines (falling, falling asleep may occur)
what drugs can be a PCA?
fentanyl, morphine
are parenteral opiate doses lower or higher than po?
lower
Name all the dosage forms for opiates
oral, IM, IV, topically (patch), buccallu, sublingual, nasal
contraindications for opiate use
allergy to opiates, acute bronchial asthma/upper airway obstruction, MAOi use in the last 14 days
cautions for opiate use
history of intolerance, serioud adverse effects, lack of efficacy of opioid therapy, pt with sleep apnea not on CPAP, COPD pts, arrhythmias
if a pt has an opiate allergy is it safe to move to a different group?
yes
how should you take someone off of an opiate?
taper it for a few days or weeks
what is addiction defined as?
increased feedback from the VTA
true or false: start at the lowest possible dose for opiate rx
TRUE
what is opiate ceiling dose dependant on?
side effect profiles
how are opiates dosed for routine use?
treat pts for 48 hours with immediate release opioids and then convert 2/3 of the estimated daily dosing to a sustained-release regimen
how is constipation prevented with opiate use?
treat empirically with docusate sodium 100mg bid
what is a rescue dose of opiates
5-15% the daily dose
what is the time of onset and peak effect of opiates?
onset: 45mins, peak effect: 60mins
how do you treat an opiate user who is already constipated?
milk of magnesia
what other therapy should you provide for your opiate using pts besides docusate sodium?
anti-emetics and diphenydramine
what are some ways to monitor opiate therapy?
use standard pain assessment tools, assess of adverse events, dependency and interference with ADLs, VS (orthostatic BP), resp. function, cardiac sounds, abdominal sounds, bowel/urinary fxn
how do you convert from one opiate to another?
equipotent doses - look them up
what should elderly pts avoid when treating pain?
NSAIDs (GI bleed, MI, stroke, HTN, decreased kidney function) use acetaminophen!
ADR of opiates in the elderly
use short term only, increased fx risk, death, CV risk (codeinde, oxycodone)
what are ebenfits of using tramadol?
decreased fx risk
MC opiates used in peds
oxycodone, hydrocodone, codeine (avoid!)
are opiates safe to use in peds?
yes - risks are not much greater in children than in adults
what is hydrocodone usually paired with?
acetaminophen
what determines the ceiling dose of vicodin
the acetaminophen - not the hydrocodone
what can vicodin treat?
moderate to severe pain
is vicodin more or less constipating than codeine?
less
what is the #1 prescribed drug in the US?
vicodin
is hydromorphone mor or less strong than morphine
7-10 times the analgesic activity of morphine
benefits of using hydromorphone?
less histamine release and no active metabolites, better tolerated in renal impairment and hemodynamic instability, less n/v, less sedation and constipation
ADR of hydromorphone?
increased respiratory depression
what is “hillbilly heroine”
oxycodone (oxycontin)
Whaich drug is 100x more potent than morphine?
fentanyl
benefits of using fentanyl?
less sedation, less constipation, less histamine release, safest in renal failure, no active metabolites, lower ADR
why are IM/IV effects seen sooner than po?
lipphilic drug so fast effects, short duratino of action
Nonopiate actions of methadone
inhibition and reuptake of monoamines (serotonin and NE), inhibition of NMDA receptors (decreases pain threshold)
benefits of methadone
long acting, ess sedation and euphoria, longest T1/2 (12-190hrs), opiate detox use
how is methadone dosed?
every 4-8 hours then once pt is stable q8-12 hours
ADR of methadone
QT prolongation
what is codeine?
less potent than morphine, prodrug converted by 2D6 into morphine
codeine is more likely to cause
constipation and nausea than other opiates
30mg of codeine = how many mg of morphine
1mg
if you cant convert codeine what does that mean?
no morphine!
75mg of demerol = how many mg of morphin
5-7.5 (1/10 potency)
ADR of demerol
seizure, delerium, tremors (d/t metabolite)
is demerol use reversible with naloxone?
no
max dose of demerol
less than 48 hours with max of 600mg every 24 hours with normal renal functioning
What are the 2 metabolites of morphine - compare them
M3G (myclonus, confusion, hyperalgesia), M6G (2-4x more potent than morphine
