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Opioid Analgesics
Neuro Module
96
Medical
Graduate
11/23/2009

Additional Medical Flashcards

 


 

Cards

Term
What type of tissue damage causes pain? (stupid question)
Definition
both actual and potential
Term
What type of pain is caused by tissue damage?
Definition
nociceptive pain
Term
What type of pain is caused by nerve damage?
Definition
neuropathic pain
Term
What type of pain (nociceptive or neuropathic) responds better to opioids?
Definition
nociceptive
Term
What two locations on the morphine molecule are important for its metabolism and analgesia?
Definition
3,6 hydroxyl groups
Term
What happens when you change the 3 or 6 hydroxyl groups of the morphine structure?
Definition
decreases its metabolism by the liver
Term
How do morphine and naloxone differ in molecular structure?
Definition
the 17 position
Term
What is the purpose of thebaine if it is an inactive opioid?
Definition
thebaine is one of the drugs in the steps to make oxycodone (hydroxylated opioid)
Term
What drug is an intermediate in the production of oxycodone?
Definition
thebaine
Term
How is the structure of heroin different than morphine?
Definition
it has two CH3 groups. one at 3 and one at 6
Term
What illegal drug is inactive but can be converted to morphine easily?
Definition
heroin
Term
What is the difference in structure between codeine and morphine?
Definition
codeine has a 3 CH3 group that makes it less metabolized and less analgesic than morphine
Term
What is another name for methylmorphine?
Definition
codeine
Term
What is true of the ADME of opioids?
Definition

absorbed well by all routes

Distributed to all metabolic tissues (less in the brain)

Metabolized by liver (glucoronidation)

polar compound after glucoronidation is excreted

Term
What does the liver do to morphine in metabolizing it?
Definition
glucoronidation into a polar molecule
Term
What are the nine effects of morphine?
Definition

analgesic (Euphoria)

respiratory depression

miosis

GI depression

Urinary retention

Cardiovascular (orthostatic hypertension)

Sphincter of Oddi contraction

Antitussive

Emesis

 

Term
How does morphine cause emesis?
Definition
it crosses into CTZ center to stimulate nausea/vomit
Term
What effects of morphine can one become tolerant to (2)?
Definition

analgesia

Respiratory depression

Term
What can't an individual become tolerant to with respect to morphine's effects?
Definition
GI depression and miosis
Term
What effect of morphine can easily be examined in a patient that you want to check complient of morphine use?
Definition
miosis
Term
What type of pain is relieved better with morphine?
Definition
the continuous dull pain
Term
What does morphine do for more sharp pain?
Definition
it still reduces it like dull pain but does not totally get rid of it
Term
How does morphine cause analgesia?
Definition
by euphoria (making one feel well and tranquil)
Term
What is dysphoria?
Definition
a feeling of fear
Term
How is emesis exacerbated in using morphine?
Definition
standing up
Term
What is the cardiovascular effect (hypertension) of morphine due to?
Definition
vasodilation secondary to histamine release
Term
What cardiovascular symptom is experienced with the use of morphine?
Definition
orthostatic hypertension/fainting
Term
How is the respiratory drive supressed with the use of morphine?
Definition
the central chemoreceptors lose senstivity causing the respiratory system to respond to peripheral hypoxia at the carotid body instead; therefore the respiratory system will not activate at the higher levels of CO2 and you become acidotic
Term
What does the increased CO2 secondary to the decreased respiratory drive cause in addition to acidosis?
Definition
causes autoregulation in the CNS leading to vasodilation and increased intercranial pressure
Term
What part of breathing is supressed by morphine (voluntary or involuntary)? Why is this important?
Definition

involuntary

 

this is important because you can reduce the respiratory effects (increased ICP and acidosis) by getting them to voluntary breath off the CO2

Term
With the use of morphine what can make the respiratory depression worse?
Definition
others CNS acting drugs (ETOH, benzos, Barbituates)
Term
What type of patient do you not want to give morphine to?
Definition
pregnant women
Term
What drug specifically takes advantage of the antitussive effect of morphine by changing the structure of morphine?
Definition
dextromethorphen
Term
What is the use for dextromethorphen?
Definition
antitussive (cough supressant)
Term
At what location does morphine have its antitussive effect?
Definition
at the pulmonary receptors
Term
How does morphine cause miosis?
Definition
stimulating parasympathetic fibers
Term
What three effects are seen in morphine's GI actions?
Definition

increases anal sphincter tone

decreases peristalsis --> diarrhea

decreases awareness to GI stimului

Term
How does morphine effect the bladder?
Definition
it contracts the detrosor muscle while at the same time contracting the urinary sphincter
Term
How does morphine make biliary colic worse?
Definition
contraction of the sphincter of oddi
Term
What are the three signs of a morphine overdose?
Definition

pinpoint pupils

coma

depressed respiration

Term
What three receptors does morphine bind to?
Definition
κ, μ, δ
Term
How do you treat codeine overdose?
Definition
naloxone (narcan)
Term
What three general areas of the brain does morphine bind to?
Definition

limbic system

reward system

pain pathway

Term
What is a major difference between the μ and κ receptor effects?
Definition
 μ will have analgesic effects at supraspinal regions and cause euphoria whereas κ will produce dysphoria and just spinal analgesia
Term
What are three endogenous stimuli for the morphine receptors?
Definition

endorphin

enkephalin

dynorphin

Term
Which morphine receptor does not produce any effect?
Definition
delta
Term
Where do the opioids have there effects specifically on nerves?
Definition

both presynaptically by increasing G-protein Gi that inhibits Ca influx (primary neuron)

 

and postsynaptically by hyperpolarizing (secondary neuron)

Term
What do opioids do to secondary neurons?
Definition
they hyperpolarize them to reduce the transmission
Term
How do opiods effect primary neurons?
Definition
they active an inhibitory G protein to reduce Ca influx and thus decrease neurotransmitter release from presynaptic neuron
Term
Why does morphine not have very good oral efficacy?
Definition
because it is greatly reduced by first pass in the liver by glucoronidation
Term
What is heroin converted to first prior to being converted to fully active morphine?
Definition
monoacetylmorphine
Term
What makes methadone a great drug to begin getting someone off heroin addiction?
Definition
it is less intense, longer acting, and slower onset
Term
Why don't addicts like to use methadone?
Definition
because it is oral and psycologically is different
Term
What are the initial signs (w/in hours) of opioid withdrawal?
Definition
dysphoria (fear)
Term
What are the main signs of opiod withdrawal in 8-16 hours (5)?
Definition

lacrimation

sweating

rhinorrhea

mydriasis

anorexia

Term
What are six signs of opoid withdrawal in 36 hrs?
Definition

muscle twitching

cramps

V/N/D

weakness

chills

increased vital signs (BP, Respiratory rate, temp)

Term
After how many hours do opioid withdrawals symptoms usually peak?
Definition
48-72 hours
Term
How long does an opioid withdrawal usually last?
Definition
ten days
Term
What is true of the withdrawal symptoms of opioids versus ETOH or barbituates?
Definition
it is not life threatening (specifically no seizures)
Term
What makes a particular opioid have a more severe withdrawal?
Definition

the longer the half life the less intense but more prolonged

 

the shorter the half life (morphine) the more intense

Term
What are the 5 strong opioid agonists in this lecture?
Definition

morphine

fentanyl

heroin

methadone

merperidine

Term
What are the four mild-moderate opioid agonists of this lecture?
Definition

CHOP

 

codeine

hydrocodone

oxycodone

prropoxyphene

Term
What are the three mixed action opioid drugs discussed in this lecture?
Definition

pentazocine

butorphanol

buprenorphin

Term
What are the two opioid antagonists discussed in this lecture?
Definition

naloxone

naltrexone

Term
What drug offers the same effect as morphine except for the GI, urinary, and biliary effects?
Definition
meperidine
Term
What drug leads to the excitatory syndrome when given in large doses?
Definition
meperidine
Term
If meperidine is given in large doses what can it cause?
Definition
excitatory syndrome
Term
What are some (3) clinical characteristics of the excitatory syndrome?
Definition

tremors

hyperreflex

and dilated pupild

Term
A patient comes to you who took a large dose of particular opioid, but she was not sure the name.   She is showing signs of tremor, hyperreflex, and dilate pupils (mydriasis).  What drug did she probably take?
Definition
meperidine
Term
What type of patients can you not use meperidine for?  Why?
Definition
cannot use meperidine for pain patients that need it for long term b/c it is readily converted to normeperidine by N-demethylation.  normeperidine has a very long half life.
Term
What is normeperidine and how is it produced?
Definition
it is the product of N-demethylation of meperidine
Term
What is true of the potency of fentanyl compared to morphine?
Definition
it is 80x more potent than morphine
Term
What is duragesic?
Definition
transdermal fentanyl
Term
What protects codeine from fast metabolism?
Definition
C3 methyl group
Term
What gene polymorphism leads to different metabolism of codeine?
Definition
CYP2D6
Term
What ethnicity has slow metabolism of codeine?
Definition
caucasians
Term
Which type of metabolizers of codeine are at greater risk of overdosing?  Ultra rapid metabolism, or slow?
Definition
ultrarapid becuase it will be converted to morphine faster by CYP2D6
Term
How does codeine become active?  What does it convert to initially?
Definition
converts to morphine in the liver by CYP2D6
Term
What age group does not have CYP2D6, what clinical implication does this have?
Definition
neonates...so dont give codeine to them
Term
How is hydrocodone given always?
Definition
with another drug (acetaminaphine or ibuprofen)
Term
What is darvon the trade name for?
Definition
propoxyphene
Term
What opioid drugs have been associated with ototoxicity?
Definition
some of the mild-moderate opoids most specifically vicodin (hydrocodone+acetaminaphin)
Term
What is pentazocine (what is its activity at receptors)?
Definition
a weak antagonist of μ and an agonist of κ
Term
What side effect does increased doses of pentazocine not induce when compared to morphine?
Definition
decreased respiratory drive is not seen with pentazocine
Term
What unique type of patients can you not give pentazocine in due to a side effect?
Definition
cardiac patients b/c it increases work of the heart
Term
What cardiac effects does pentazocine have?
Definition
increased HR and BP
Term
Due to the fact that pentazocine is a μ antagonist what can it cause if given to a opioid dependent patient?
Definition
it can cause a withdrawal 
Term
What is pentazocine combined with in the oral form and why?
Definition
it is combined with naloxone (Talwin-NX) to prevent abuse
Term
What is the reason behind given Talwin-NX?
Definition
In giving oral talwin NX you are given pentazocine with a small does of naloxone.  So when you take talwin-NX orally, the naloxone is metabolized by first pass and has not antagonistic effect.  However, if you were to abuse the drug and change its form to enable it to be injected, you would not have the benefit of first pass and it would induce a withdrawal symptom
Term
What are two uses for naloxone?
Definition
it is used for reversal of overdose and used to determine if a suspected individual is abusing opioids (will cause an acute withdrawal syndrome for up to 2 hours in a positive abuser)
Term
What mixed opioid is more potent and longer lasting than morphine?
Definition
buprenorphine
Term
What is buprenorphine derivied from?
Definition
thebaine
Term
WHat is the difference in administration of naloxone and naltrexone?
Definition
naltrexone can be administered orally
Term
What is the use of naltrexone?
Definition
it is great for highly motivated past opioid abusers who are afraid that they may try opioids and dont want to lose all their work in detoxing
Term
Which has a higher length of duration?  Naltrexone or Naloxone?
Definition
Naltrexone
Term
What drug is demerol?
Definition
meperidine
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