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Pharmacology
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Which of the following is true regarding seizures as one of the multiple side effects from the use of opioids?
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(A) Morphine and related opioids can cause seizure activity when moderate doses are given
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(B) Seizure activity is more likely with meperidine, especially in the elderly and with renal dysfunction
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(C) Seizure activity is mediated through stimulation of N-methyl-d-aspartate (NMDA) receptors
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(D) Naloxone is very effective in treating seizures produced by morphine and related drugs including meperidine
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(E) Seizure activity is most likely related with the fact that opioids stimulate the production of γ-aminobutyric acid (GABA)
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(B) Extremely high doses of morphine and related opioids can produce seizures, presumably by inhibiting the release of GABA (at synaptic level).
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Normeperidine a metabolite of meperidine is prone to produce seizures and tends to accumulate in patients with renal dysfunction and in the elderly.
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Naloxone may not effectively treat seizures produced by meperidine.
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Which of the following is true regarding respiratory depression related to the use of opioids?
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(A) Opioid agonists, partial agonists, and agonist/antagonists produce the same degree of respiratory depression
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(B) Opioids produce a leftward shift of the CO2 response curve
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(C) Depression of respiration is produced by a decrease in respiratory rate, with a constant minute volume
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(D) Naloxone partially reverses the opioid-induced respiratory depression
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(E) The apneic threshold is decreased
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(E) Opioids produce a dose-dependant respiratory depression by acting directly on the respiratory centers on the brainstem. Partial agonist and agonist-antagonist opioids are less likely to cause severe respiratory depression, as are the selective K-agonist.
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Therapeutic doses of morphine decrease minute ventilation by decreasing respiratory rate (as oppose to tidal volume).
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Opioids depress the ventilatory response to carbon dioxide; the carbon dioxide-response curve shows a decrease slope and rightward shift.
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The apneic threshold is decreased and also the increase in ventilatory response to hypoxemia is blunted by opioids.
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Naloxone can effectively and fully reverse the respiratory depression from opioids.
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The use of which of the following opioids would produce the greatest incidence of delayed respiratory depression?
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(A) 25 μg intravenous (IV) fentanyl (bolus)
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(B) 4 mg IV morphine (bolus)
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