CHAPTER 14: OPIOIDS Flashcards
NARCOTICS: purpose
provide treatment for acute or chronic pain
- effect on brain and spinal cord, alter impulses from peripheral nerves
PAIN: 3 types
- PAIN is subjective, ppl respond differently
nociceptive: caused by direct pain receptor stimulus (direct damage to body)
neuropathic pain: caused by nerve injury (ex: diabetes)
psychogenic pain: associated w emotional, psychological, or behavioral stimuli
PAIN: acute v. chronic
acute: caused by tissue injury, person aware of injury and leads to seek care
chronic: constant/intermittent pain, keeps occurring past time area would be expected to heal, interfere w daily living
Narcotics: opioids intro
- 3 types
-primary effect
Opioids: natural, semisynthetic, or synthetic
- produce morphine like effects
primary effect: relieve pain from surgery, injury, or chronic disease
substance of abuse
endogenous neurotransmitters
- molecules
- found where
narcotics have diff type of opioid receptors that respond to naturally occurring molecules/pain reducers:
- enkephalins
- dynorphins
- endorphins
found in CNS, peripheral nerves, gi tract cells
diff types of opioid receptors details
Mu: primary pain blocking (analgesia), resp depression
delta: modulate pain transmission, react w enkephalins in periphery
kappa: some analgesia, mydriasis, sedation
Opioid Receptors MOA
- goal?
all G PROTEIN COUPLED RECEPTORS
- Gi–> inhib adenylyl cyc, activate K+ channel, deactivate Ca2+ channel (hyperpolarize)
open and close based on AP
GOAL IS LESS TRANSMISSION OF PAIN SIGNAL
Narcotic Agonists: therapeutic use
- agonist to specific opioid rec in CNS to produce analgesia, euphoria, and sedation
-relieve mod/severe acute/chronic pain
-preop meds
-analgesia during anesthesia
-antitussive (anti COUGHING)
Narcotic Agonists: MORPHINE
- receptor
- actions
- routes
- Mu receptor
ACTIONS: euphoria, resp depression (dose dep), miosis, emesis, constipation, histamine release, dec release hormones
high dose: hypotens/bradycardia
ROUTES: SC, IV, IM, oral only ER form
some metab still active
Narcotic Agonists: Codeine
- actions
- cautions
- less potent than morphine–> convert into morphine in LIVER
ACTIONS: analgesia, antitussive
CAUTIONS: life-threatening resp depression, death in children
Narcotic Agonists: Oxycodone and Oxymorphone
- stronger or weaker
- formulations of each
- semisynth analog of morphine
parenterally STRONGER than morphine - formulate w aspirin and acetaminophen sometimes
oxycodone: PO ER form
oxymorphone: PO immediate acting and ER (also avail IM labor, SC, IV)
Narcotic Agonists: Fenatnyl
- synthetic
- use for anesthesia (IV, epidural, intrathecally)
- oral transmucosal for treat cancer pain
Narcotic Agonists: Methadone
- synthetic
- mu rec AGONIST
- SNRI and NMDA ANTAGONIST
- for nociceptive and neuropathic pain
- less euphoria, longer duration compared to morphine
- used for controlled withdrawal of abusers
- long half life, accum in fat tissue, can lead to toxicity
narcotic agonists: ADVERSE EFFECTS
- CNS, CV, GI, GU, Others
CNS: lightheaded, dizzy, anxiety, fear, psychoses, hallucination, impaired mental process
CV: orthostat hypo
GI: nausea, vomit, constipation (OIC)
GU: ureteral spasm, urine retention, lose libido
OTHER: sweat, physical/psych dependence, withdrawal
narc induced respiratory depression, apnea, cardiac arrest, shock
methylnaltrexone- CONSTIPATION
- opioid antagonist
- mu receptor blocked–> responsible for constipation
- SC once a day
- doesn’t cross BBB
antagonist to treat the effect of agonists
DRUG-DRUG Interactions
barbiturates, phenothiazines, MAOIs–> resp depression, hypotension, sedation/coma
SSRI, MAOI, TCA–> inc risk of serotonin syndrome if taken w tapentadol (blocks NE reuptake)
MIXED AGONISTS/ANTAGONISTS
- narcotic agonists-antagonists
- act on certain opi rec but block others
- less abuse potential
- similar analgesic effect like morphine
narcotic agonists-antagonists is/isnt used for which kinds of PTs
- opioid naive PT: never taken opi before, drug is used to treat their pain
- PT previously exposed to opi, may worsen withdrawal
narcotic agonists-antagonists: therapeutic uses
- relief mod/severe pain
- pre-anesthetic med, supplement surgical anesthesia
- relieve chronic pain in those susceptible to narcotic dependence
Buprenorphine
- type of agonist
- partial ago of mu, antagonist of K rec
- lipophilic
- high affinity for receptors/long duration action
- ceiling effect: less euphoria, lower abuse potential
- office based treatment
Pentazocine
- agonist K, partial agonist mu receptors
- less euphoria
- HIGH DOSE= resp depression, inc BP, tachy, hallucination
- hospital settings
DRUG DRUG INTERACTIONS: mixed ago/antagonists
tripelennamine: inc hallucinogenic and euphoric effect w pentazocine (Ts and Blues)
trip= antihistamine
NARCOTIC ANTAGONISTS
- bind strongly to opi rec but DON’T activate
- BLOCK receptor, reverse effects of opioids (resp depression and sedation)
Narcotic antagonists: Indications
- complete or partial reversal or narcotic depression
- opi overdose
Narcotic Antagonists (2)
Naloxone/narcan: reverse AE of narcotics, nasal or autoinjection
- COMPETITIVE antagonists of ALL 3 RECEPTORS
Naltrexone: orally, manage alc/narcotic dependence AFTER PT is detoxified
- tablet or injection
- COMPETITIVE antag of ALL 3 receptors
- LONGER duration of action
hepatotoxicity
Narcotic Antagonists: Adverse Effects
CNS: excitement, reversal analgesia
CV: tachy, BP changes, dysrhythmias, pulmonary edema
Acute Narcotic abstinence syndrome
nausea, vomit, tachy, hypertension, anxiety
- naloxone challenge should be administered before giving naltrexone to avoid acute reactions
naloxone challenge: off drug at least 7-10 days before moving to naltrexone, we use naloxone bc of shorter duration of action so we don’t risk withdrawal symptoms
