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56 Cards in this Set
- Front
- Back
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What opiate receptor do morphine, and most opioids work at?
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μ-receptor
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How/where are opioids metabolized?
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Conjugated with glucuronic acid in the liver
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How does the excretion of morphine break down?
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90% urinary, 10% bile
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How does an oral dose compare to an I.M. injection of morphine?
(in terms of peak effect) |
1/5 - 1/6 of the peak effect
(due to 1st pass metabolism and slow absorption) |
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How does morphine withdrawal compare
to that of EtOH, BDZs, and barbiturates? |
LESS severe
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What are the 3 major effector systems of the μ-receptor?
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Opening of K channels
Decreased opening of Ca channels Inhibition of adenylate cyclase |
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Analgesic effects are due to morphine action where (in body)?
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Spinal cord and supraspinal structures
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What is allodynia?
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Pain caused by previously innocuous stimuli
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What type of pain is best relieved by morphine?
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Dull, continuous pain
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What effects do TCAs and SSRIs have on the effects of opioids?
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Potentiate the analgesic effects
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By what mechanism are NSAID analgesic effects additive with morphine's?
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Decreased PGs --> Decreased activation of nociceptors
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Respiratory depression is due to morphine action where (in body)?
What aspect of respiration is primarily affected? |
Medulla oblongata and pons
Rate is primarily affected NOTE: in a morphinized pt. hypoxia may become force behind resp. drive! |
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Which opioid is the preferred one for cough?
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Dextrometorphan
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What do opioids directly affect to cause N&V?
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Chemotrigger zone and Vestibular system
Note: after 1st dose, refractoriness to N&V is usually seen |
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Opioid induced nausea can be antagonized by which two drugs?
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Prochlorperazine
Phenothiazine |
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What effect do opioids have on body temperature?
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Cause HYPOthermia
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What are pin-point pupils a sign of?
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Toxicity
This effect does NOT decrease w/ tolerance |
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Opioids can cause dramatic hypotension in what type of pts.?
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Hypovolemic
(depress sympathetic tone and baroreflexes) |
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Where in the GI/GU tracts do opioids act?
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ON NERVE PLEXI
(NOT on smooth muscle or secretory cells) |
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What type of contractions do opioids INCREASE in the GI tract?
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NON-propulsive (spasmogenic)
NOTE: can exacerbate epigastric pain and biliary colic |
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What drug is good in combo w/ opioids to treat diarrhea?
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Atropine
(antagonizes spasmogenic action, potentiates anti-propulsion) |
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What takes higher doses of opioids?
Analgesia or GI effects |
Analgesia
The gut is sensitive to far lower doses |
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How does naloxone impact codeine's anti-tussive effect?
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REVERSES it
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What happens to codeine to change it to morphine?
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It gets demethylated
This happens SLOWLY |
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These two are identical to morphine, except MORE potent
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Oxymorphone
Hydromorphone |
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These two are equipotent w/ morphine, but better absorbed orally?
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Oxycodone
Hydrocodone |
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This drug has a slow release form that is widely abused
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Oxycodone
Oxycontin is the slow release form |
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What are hydro/oxy-codone used for?
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Low - moderate pain
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What happens to heroin to change it to morphine?
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It gets deacetylated
This happens RAPIDLY |
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Levorphanol
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Optic isomer has no analgesic effects
BUT, has great anti-tussive effects |
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How does naloxone impact dextrometorphan's anti-tussive effect?
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CANNOT reverse it
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What opioid is preferred for obstetrical analgesia?
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Meperidine
Has a short half-life Causes less respiratory depression (in child) Does NOT alter labor |
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Meperidine important points
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Metabolized into normeperidone, which is excitatory
LESS spasmogenic than morphine Produces less constipation and urine retention Does NOT inhbit cough Does NOT alter labor |
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How is diphenoxylate administered?
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Can ONLY be given ORALLY
(very insoluble, so it is NOT abused much) |
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What is diphenoxylate primarily used for?
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Used in combo w/ atropine for diarrhea
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What is (su)fentanyl primarily used for?
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In combo w/ droperidol for anesthesia
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Which is more potent?
Morphine or (su)fentanyl |
Fentanyl is ~80 times more potent
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This drug is often prescribed in lieu of codeine
What is it? Why is it? |
Propoxyphene
Less effective, BUT abuse liability is lower |
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Methadone is used for what (2)?
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Relieve moderate to severe pain
Replacement therapy of opiate addiction |
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How is methdaone superior to morphine?
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Better abosrption, among other things
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What is special about 1-acetylmethadol?
What is it used for? |
VERY LONG LASTING (given every 2-3 days)
Deacetylated to methadone Used in replacement therapy of opiate addiction |
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What is the receptor action of pentazocin?
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μ-receptor antagonist
powerful κ-receptor agonist |
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Which is more potent?
Penatazocin or Morphine |
Morphine
(pentazocin is only 20 - 50% as potent) |
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Why is pentazocin not used in CAD?
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High doses --> increased BP & HR, and increased NE & Epi
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What causes psychotomimetic effects of opioids?
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Binding to σ and PCP receptors
(endogenous opioids do NOT bind these) |
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This drug is equipotent w/ diphenoxylate and is used only for diarrhea
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Loperamide
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Degree of opioid withdrawal depends on what two factors?
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Degree of dependence (related to dosage, etc)
Half-life (the shorter --> the more intense) |
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How is naloxone administered?
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MUST be given I.V.
(ZERO oral bioavailability) |
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How does naltrexone compare to naloxone?
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Same effects
Typically given orally Lasts much longer |
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How is clonidine used in the context of opiates?
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Adjunct to psychotherapy for withdrawal
Attenuates intensity of autonomic components Reduces psychological craving |
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Which opiate is best suited for use in treatment of GI/GU tract disorders?
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Meperidine
It is less spasmogenic than others |
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What side effect can be problematic w/ Meperidine used in pregnancy?
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Respiratory distress in the infant
NOTE: this is still less than that caused by morphine |
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What effects do opioids have on urinary output?
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DECREASE it
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What effect do opioids have on sugar levels?
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Cause HYPERglycemia
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What effect do opioids have on gonadotrophic hormones?
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DECREASED their release from the pituitary
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Opioids w/ less abuse potential than morphine (3)?
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Diphenoxylate
Propoxyphene Pentazocin |
