Pain, opioids, drug abuse

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Pain, opioids, drug abuse
2013-10-27 14:58:25
pharm week

pain, opioid agonists and antagonists powerpoint, chapter 28, chapter 37
Show Answers:

  1. define acute pain
    • from illness or injury
    • ends at some point, with or without medical treatment
  2. what is the drug of choice to treat myocardial infarction?
  3. define chronic pain
    • persists >3 months
    • persists >1 month after fixing acute tissue injury
    • accompanies non-healing lesion
  4. cardiovascular effects of uncontrolled pain
    • increased heart rate
    • vasoconstriction (systemic vascular resistance)
    • increased BP
    • increased myocardial oxygen consumption
    • altered regional blood flow
    • deep vein thrombosis
  5. respiratory effects of uncontrolled pain
    • decreased lung volumes
    • decreased cough effort
    • increased sputnum retention
    • hypoxemia
  6. effects of uncontrolled pain on GI tract
    • decreased gastric/bowel motility
    • urinary retention
  7. psycho-neuro-endocrine effects of uncontrolled pain
    • increase of epinephrine
    • glucagon release -> increased glucose levels -> healing prolonged and increased risk of infection
    • anxiety, fear, sleeplessness
  8. what are adjuvants?
    • any non-pharm method for controlling pain
    • examples: elevation/positioning, ice, heat, distraction, etc.
  9. what are the WHO's 3 steps in approaching chronic pain?
    • 1.  Non-opioid +/ adjuvant
    • 2.  opioid +/ non-opioid +/ adjuvant
    • 3.  opioid +/ non-opioid +/ adjuvant

    between steps 2 and 3, change (usually increase) dose of opioid
  10. what kind of analgesic does not have a dose ceiling?
  11. 3 opioid receptors
    • Mu- most common
    • Kappa - weak, involved with agonist-antagonists
    • Delta - don't interact with opioid analgesics
  12. effects of mu activation by opioids
    • respiratory depression
    • cough suppression
    • orthostatic hypotension
    • constipation
    • nausea/vomiting
  13. what is the most commonly used opioid (agonist)?
  14. what three actions of morphine help manage pain?
    • 1)  reduce perception of pain
    • 2) psychological response to pain is reduced
    • 3) induces sleep
  15. true or false: morphine affects all the senses and causes loss of consiousness
    false: does not affect other senses, does not cause loss of consciousness
  16. morphine is most effective against what kind of pain?
    • constant, dull pain
    • moderate to severe
  17. what can happen with prolonged use of morphine?
    tolerance/physical dependence
  18. what is the main adverse effect you should be on the lookout for when administering morphine?  who is most at risk?
    • respiratory depression
    • -opiate naive
    • -compromised pulmonary status
    • -neuromuscular disease
    • -very old or very young
  19. when should you titrate opioid doses?
    • when they are not effective enough
    • every 2 hours with short-acting agents
    • until >50% reduction in pain
    • when there is breakthrough pain or need a rescue dose
  20. why does only a small amount of each dose of morphine actually produce analgesic effects?
    • poor lipid solubility
    • can't cross BBB easily
    • only small fraction reaches CNS (needs to get to CNS to relieve pain)
  21. should oral doses of morphine be larger or smaller than parenteral doses?  why?
    • larger
    • first pass metabolism
  22. methods of morphine administration
    • PO
    • IM
    • IV
    • subQ
    • epidural
    • intrathecal (injection into spinal cord)
    • suppositories
  23. how should you titrate opioid doses?
    • small increments
    • 25-100% of baseline dosage (based on pain rating)
  24. True or false: Once opioid administration ends, all side effects also end.
    False: respiratory depression lasts longer than analgesic effects, and longer than antagonist effects (i.e. when administering Narcan)
  25. PRN
    As needed
  26. ATC
    around the clock
  27. PCA
    patient controlled analgesia
  28. what should you do if a patient is opioid naive?
    assess response to the first dose carefully
  29. true or false: opioids always cause a drop in BP
    false: if patient is well hydrated, BP should not drop
  30. are opioids better tolerated when the patient is lying down (supine) or sitting up?
    Supine: if upright, may cause nausea/vomiting, orthostatic hypotension/dizziness
  31. what's fentanyl?
    • an opioid with rapid onset, short duration of action
    • 100x more potent than morphine
    • used for surgical anesthesia
  32. true or false: as tolerance of opioids increases, tolerance of all side effects also increases
    false: you will always be constipated
  33. what are the withdrawal effects of opioids?
    insomnia, pain, restlessness, increased GI activity
  34. what should you know about meperidine (Demerol)?
    • it is a BAD DRUG and you shouldn't use it!
    • -> seizure risk

    • -short half life
    • -reacts poorly with other drugs
    • -continued use can cause toxicity due to build up
  35. when is meperidine ok to use?
    • short term
    • preferred for labor
    • less likely to depress fetal respiration and uterine contractions
    • -have naloxone on hand
  36. what is codeine good for treating?
    • cough
    • mild to moderate pain
  37. if opioids make a patient nauseous, what drug should you avoid giving them?
    • codeine
    • causes more emesis
  38. true or false: codeine is always an effective analgesic in all patients
    false: some people lack the enzyme to convert it to morphine -> no analgesic effect
  39. if codeine is an opioid, why might it have a dose ceiling?
    often combined with other drugs like acetaminophen that do
  40. if an agonist-antagonist is given along (not with a pure opioid agonist), what will the effect be?  If taken with an agonist?
    • alone: analgesia
    • with agonist: antagonizes analgesia produced by agonist
  41. what's Butorphanol?  how does it interact with morphine?
    adverse effect?
    • weak agonist at kappa
    • antagonist at mu: kicks off morphine
    • may cause withdrawal
    • ae: risk fatal dysrhythmia
  42. when should you give naloxone (Narcan)?  
    what is the goal?
    mode of administration?
    • opioid antagonist: give for opioid overdoses
    • goal: stop respiratory depression
    • IV
  43. how should Narcan be administered (related to duration of action)?  what can occur if administered incorrectly?
    • short duration of action: small, repeated doses
    • give too much -> withdrawal
  44. drugs that relieve pain without causing loss of consciousness
  45. general term for any drug, natural or synthetic, that has actions similar to those of morphine
  46. term for a drug that may mean an analgesic, a CNS depressent, and/or any drug capable of causing physical dependence
  47. define tolerance
    a larger dose is required to produce the same response that could formerly be produced with a smaller dose
  48. what is cross tolerance?
    resistance to a medication as a result of tolerance to a pharmacologically similar drug
  49. How should opioid administration be stopped?
    gradually -> minimize withdrawal (abstinence syndrome)
  50. what affect does regular use of opioids during pregnancy have?
    physical dependence in fetus -> withdrawal after delivery
  51. Three classic signs of opioid overdose:
    • coma (profound- patient can't be aroused)
    • respiratory depression
    • pinpoint pupils (abnormally constricted pupils)
  52. is it better to administer opioids on a fixed schedule, or PRN?  why?
    fixed schedule (breakthrough pain may be managed with additional rescue doses)

    prevents needless discomfort, reduces patient anxiety related to pain
  53. True or false: pharmaceutical scientists have produced new opioid analgesics that are superior to morphine due to their low potential for respiratory depression and abuse.
    false: new opioid agonists have been created, but none are considered superior to morphine.  All still have similar adverse effects.
  54. oxycodone
    similar pain relief to codeine
  55. hydrocodone
    • vicodin
    • most prescribed drug in US
    • similar pain relief to codeine
    • always combined with other drugs
  56. define drug abuse
    drug use that is inconsistent with medical or social norms
  57. define addiction
    continued use of psychoactive substance despite physical, phsychologic or social harm

    physical dependence is NOT the same as addiction
  58. Is it common for patients to experience physical dependence when opioids are used short term for pain relief?
    • No, rarely
    • when physical dependence does occur, developing addictive behavior is also rare
  59. what is the best way to minimize physical dependence and abuse of opioids?
    administration of lowest effective dosages for shortest time needed
  60. what is PCA?
    • Patient Controlled Analgesia
    • allows patient to self-administer opioids parenterally on PRN basis
  61. who is a candidate for PCA?
    • postoperative patients
    • patients experiencing pain as a result of:
    • cancer
    • trauma
    • MI
    • labor
  62. how is PCA controlled to prevent overdose?
    • time control mechanisms
    • limits dosage allowed per hour
    • regulates minimum interval between doses
  63. Why is PCA preferable to regular IM injections?  (besides not having to get stuck with needles a bunch)
    • provides more regular, small doses versus larger doses
    • avoids peak/troughs, keeps plasma drug levels more steady
  64. are opioids good for alleviating pain in head injuries?
    • use with caution: head injuries can cause resp. depression and elevation of ICP
    • opioids may exacerbate
  65. why should you limit opioid use in cancer patients?
    trick question!  You shouldn't!  They've got cancer, we're much more worried about that than them getting hooked on their meds.  give them as much as they need to relieve the pain.
  66. what are some guidelines for safely using opioids to treat non-cancer chronic pain?
    • try non-opioids first
    • discuss benefits and risks with patients
    • try to use only one prescriber and one pharmacy
    • comprehensive follow-ups
    • stop if they don't work
    • document everything
  67. Intense, subjective need for a particular psychoactive drug
    psychologic dependence
  68. what is the reward circuit and what role does it play in drug addiction?
    system in brain that normally reinforces behaviors that contribute to survival

    addictive drugs activate reward circuit, release dopamine -> reward/reinforce drug use
  69. what phenomenon occurs during synaptic remodeling in the brain with use of addictive drugs?  how does this encourage addiction?
    down regulation

    • 1) brain produces less dopamine
    • 2) fewer dopamine receptors

    • -> reduced response to drug, natural stimuli also can't activate circuit as well
    • -> less pleasure from natural stimuli makes user depressed
  70. what is the principal federal legislation addressing drug abuse?
    • Controlled Substances Act
    • (Comprehensive Drug Abuse Prevention and Control Act of 1970)
  71. Under the Controlled Substances Act, drugs are assigned to one of five categories: Schedule I, II, III, IV, V.  Drugs in which category have high potential for abuse and no approved medical use?
    Schedule I
  72. Drugs in Schedules II-V all have approved medical uses.  What determines their assignment to each category?
    potential for drug's abuse/ability to cause dependence
  73. Of drugs with medical applications, drugs in which category (Schedule I-V) have the highest potential for abuse/dependence?
    • Schedule II
    • (Schedule I has no medical use)
  74. What does the label on Schedule II-V drugs prohibit?
    transferring of the drug to any person other than the patient for whom it was prescribed
  75. what role do prostaglandins and substance P play in pain reception?
    can enhance sensitivity of pain receptors to activation
  76. what role do enkephalins and beta-endorphins play in pain reception?
    • suppress pain conduction 
    • (endogenous opioid compounds)
  77. pain that results from injury to tissues
    • nociceptive pain
    • -may be somatic or visceral
  78. pain that results from injury to peripheral nerves
    neuropathic pain
  79. somatic pain v. visceral pain descriptions
    • somatic: localized, sharp
    • visceral: vaguely localized, diffuse/aching
  80. neuropathic pain descriptions
    burning, cold, shooting, jabbing, tearing, numb, dead
  81. why can switching from one opioid to another be beneficial?
    • different opioids have different side effects
    • switching may decrease adverse effects while maintaining pain control
  82. when can breakthrough pain occur and how does it develop?
    • can occur any time in dosage schedule
    • develops quickly, reaches peak intensity in minutes, may persist for hours