Opioids Flashcards
Opiate receptors
Mu, kappa, delta
Opiate
derived from opium, natural, morphine
Opioid
having properties similar to drugs derived from opium, semisynthetic- heroin, hydromorphone, oxycodone, hydrocodone, synthetic-methadone, meperidine
Strong mu agonists
Morphine, fentanyl, hydrocodone, hydromorphone, oxycodone, methadone, meperidine, codeine, sufentanil, heroin, oxymorphone
Partial mu agonists and mixed agonist antagonists
nalbuphine (Nubain), buprenorphine (Subutrex), pentazocine (Talwin), Tramadol (Ultram)
opioid antagonists
naloxone (Narcan), Naltrexone (Revia)
Mu receptor
located in brainstem, spinal cord, and limbic region, analgesia, respiratory depression, euphoria, reduced gastric motility, physical dependence
Delta receptor
located in brainstem and limbic region, dysphoria, hallucination, some analgesia
Kappa receptor
located in brainstem and spinal cord, analgesia, sedation, dysphoria, miosis
dopamine is released when
mu receptors are stimulated which stimulates feelings of pressure
endorphines, enkephalins
provide natural amount of pain relief
norepinephrine, serotionin
plays an inhibitory role in the descending tract, explains why antidepressants can be used for pain control
Pain receptors
opioid receptors, endogenous opioids and monoaminergic substances are released when pain is felt and play important roles in transmission of pain, many receptors provides many targets
Classification of opioids
weak agonists, strong agonists, mixed agonist-antagonists, other analgesic, antagonists, most are strong mu agonists, modest kappa agonists, and weak delta agonists
Analgesia/ euphoria
tolerance will develop, requiring increased dosing, no ceiling effect to analgesia with tolerability being only true limiting factor, provide pt is tolerating, no such thing as a max dose
Depression cough reflex
Opioids can be used as cough suppressants, efficacious but use limited by DEA red tape
Treatment of nausea
related to stimulation of chemoreceptor trigger zone in medulla
ADRs of opioids
nausea/vomiting, hypotension, constriction of pupils, increased tone of circular smooth muscle, constipation, urinary retention, sedation, delirium, respiratory depression, urticaria/ pruritis
Codeine
for mild-moderate pain, usually T3, weak by itself, considered very good antitussive, usually combined with APAP, prodrug lacks 2D6
Codeine ADRs
N/V/C less sedation than opioids, higher incidence of histamine release, keep APAP content in mind
Hydrocodone (Norco)
1 prescribed drug in the country, only PO, usually with APAP, branded under Lorcet, Lortab, Norco, Vicodin, and more, can see used q3h
Hydrocodone new product
Zohydro ER, BID, $$$, controversial, DEA CII, used for moderate to severe, no sig ADRs
Oxycodone
PO only, long and short acting, often reserved for severe pain, good alternative to APAP
Oxycodone combos
Oxycontin-extended release, Oxy IR, Roxicodone- immediate release caps, Oxyfast/Roxicodone- oral solutions, Percocet- with APAP, percodan- w/ aspirin, also combo with ibu
Morphine
first line for moderate to severe pain, T1/2- 1.5-2 hours, lasts 3-5 hrs, metabolized to renally excreted active metabolite, dose adjust required, multiple dosage forms available
Morphine MOA
strong opioid agonist, selective to mu receptor w/ primary actions in brain
Morphine brands
avinza-once daily, kadian- daily or q12h, MScontin, Oramorph SR- q8-12h, MS IR- immediate release tab, suppository, and parenteral injection
Morphine dosing
largely dependent on pt level of tolerance, renal funct, pain and more, dosing of parenteral narcotics should never be one size fits all, can be used in peds
Hydromorphone (Dilaudid)
more potent than morphine, IV and PO, 1mgIV=7 mg morphine, use q3h, usually reserved for pt whose pain is not controlled w/morphine, safer in renal failure
Meperidine (Demerol)
PO and IV, short duration (2-4 hrs), active metabolite- normeperidine very long duration, avoid in renal insufficiency, can trigger seizures, don’t use more than 48 hrs, better options available
Methadone
long acting, synthetic opioid mu agonists, half life 24-36 hrs, rarely used for pain control, but for heroin addicts
Fentanyl
highly lipophilic, synthetic and structurally related to meperidine, more potent mu agonists, shorter acting, preferred in hemodynamically instability and bronchospasm
Fentanyl dosage forms and devices
IV, buccal tablet (Fentora), Lozenge (Actiq), transdermal patch (Duragesic)
Fentanyl advantages/ disadvantages
DOC in icu, sustained release opioid, good for poor compliance, good if drug abuse, available as generic, dis: delay onset 12-18 hrs, must remove old patch
Most commonly used PCAs
morphine, hydromorphone, fentanyl
PCA advantages/disadvantage
prevents chasing pain, pt involved w/ care, dec total amt of drug used, free up nursing time; dis avoid in certain pts, transition to PO difficult, family pushing button
Pt may benefit from CI if
undergoing major surgery, severe pain expected for long time, continually maxing out pump settings, pain not controlled and not experiencing ADRs, baseline opioid tolerance exists, awakening at night
Symptoms of opioid toxicity
CNS depression, respiratory depression, pin point pupils
Treatment of opioid toxicity
respiratory support, give Naloxone (Narcan), IV
Naloxone (Narcan)
used to reverse opioid toxicity, competes for receptors, works very fast, may titrate up to desired degree of reversal, always keep in mind half life of drug, syms may subside then return
Opioid withdrawals
occurs when pt that is physically dependent on opioids undergoes repid cessation of exposure to opioids, not just concern for addicts
Common symptoms of opioid withdrawal
yawning, irritability, rapid breathing, rhinorrhea, salivation, sweating, N/V/D, dilation of pupil, HTN, tachy
Mixed agonists/Antagonist drugs
pentazocine (Talwin), Nalbuphine (Nubain), Butorphanol (Stadol)
Mixed agonists/Antagonists
not first line option, lower abuse potential, can cause withdrawal with opioid pts, lacks euphoric effects, OB pts
Buprenorphine/Naloxone (Suboxone)
used for treatment of opioid dependence, mixed opioid agonist/antagonist, attaches to empty opioid receptors, blocks other opioids from attaching, begin at first signs of withdrawal, license required
Buprenorphine
partial agonist at mu receptor and antagonist at kappa receptor
Naloxone
antagonist at mu receptor
Tramadol (Ultram, Ultracet)
centrally acting opioid analgesic for moderate pain, dual mech of action, binds to mu and inhibits norepi and serotonin reuptake, used for mild-mod pain
Tramadol (Ultram, Ultracet) ADRs
less sig, N/V/C, dizziness, resp depress, abuse tolerance less concern, seizures, caution with SSRI, SNRI, TCA, avoid in MAO-Is, dec with renal impaired and elderly
Opioids are pri ary agents used
short term unless terminal, used with non-opioids, IV options work faster, great for post-op, better to not chase pain, be mindful of acute on chronic
