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