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Questions and Answers
What is the effect of administering opioids in combination with nitrous oxide during anesthesia?
What is the effect of administering opioids in combination with nitrous oxide during anesthesia?
Which combination of medications is likely to cause significant decreases in mean arterial pressure?
Which combination of medications is likely to cause significant decreases in mean arterial pressure?
Why might large doses of opioids be ineffective after an initial cardiovascular response to painful stimulation?
Why might large doses of opioids be ineffective after an initial cardiovascular response to painful stimulation?
What role do opioids play in relation to the myocardium?
What role do opioids play in relation to the myocardium?
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What occurs when fentanyl is administered in the absence of prior administration of diazepam?
What occurs when fentanyl is administered in the absence of prior administration of diazepam?
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What is a primary mechanism by which opioid agonists cause depression of ventilation?
What is a primary mechanism by which opioid agonists cause depression of ventilation?
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What effect does opioid-induced ventilatory depression have on carbon dioxide levels?
What effect does opioid-induced ventilatory depression have on carbon dioxide levels?
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Which factor is likely to influence the magnitude of opioid-induced depression of ventilation?
Which factor is likely to influence the magnitude of opioid-induced depression of ventilation?
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What characterizes the breathing changes associated with high doses of opioids?
What characterizes the breathing changes associated with high doses of opioids?
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Which receptors are now recognized to have diverse roles beyond being classified as opioid receptors?
Which receptors are now recognized to have diverse roles beyond being classified as opioid receptors?
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What is the role of β-arrestin in opioid-induced ventilatory depression?
What is the role of β-arrestin in opioid-induced ventilatory depression?
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How does the reversal of opioid-induced ventilatory depression typically impact analgesia?
How does the reversal of opioid-induced ventilatory depression typically impact analgesia?
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What symptom indicates a compensatory response to the depression of ventilation caused by opioids?
What symptom indicates a compensatory response to the depression of ventilation caused by opioids?
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What structural feature is common to most opioid agonists?
What structural feature is common to most opioid agonists?
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Which opiate derivative is formed by substituting a methyl group for the hydroxyl group on carbon 3 of morphine?
Which opiate derivative is formed by substituting a methyl group for the hydroxyl group on carbon 3 of morphine?
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What distinguishes synthetic opioids from semisynthetic opioids?
What distinguishes synthetic opioids from semisynthetic opioids?
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Which of the following opioid receptors is named after the ligand morphine?
Which of the following opioid receptors is named after the ligand morphine?
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What impact do acetyl groups on carbons 3 and 6 of morphine have?
What impact do acetyl groups on carbons 3 and 6 of morphine have?
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Which group of synthetic opioids includes fentanyl?
Which group of synthetic opioids includes fentanyl?
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What is the primary responsibility of μ-opioid receptors?
What is the primary responsibility of μ-opioid receptors?
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What characteristic of opioid receptors is NOT true?
What characteristic of opioid receptors is NOT true?
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Which synthetic opioid is known for having a very high degree of potency compared to morphine?
Which synthetic opioid is known for having a very high degree of potency compared to morphine?
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What effect does activation of κ receptors have compared to μ receptors?
What effect does activation of κ receptors have compared to μ receptors?
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What role do β-arrestins have in the function of opioid receptors?
What role do β-arrestins have in the function of opioid receptors?
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How can the efficacy and tolerability of opioid agonists potentially be improved?
How can the efficacy and tolerability of opioid agonists potentially be improved?
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What is the presumed mechanism by which intraarticular morphine produces analgesia?
What is the presumed mechanism by which intraarticular morphine produces analgesia?
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What is a likely outcome of a lower pKa for an opioid compound?
What is a likely outcome of a lower pKa for an opioid compound?
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Which of the following is least likely to be affected by the activation of κ receptors?
Which of the following is least likely to be affected by the activation of κ receptors?
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What do δ receptors respond to, and what is their primary role?
What do δ receptors respond to, and what is their primary role?
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What is the primary reason for opioid-induced cough?
What is the primary reason for opioid-induced cough?
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How long does it typically take for pharmacodynamic tolerance to develop with analgesic doses of morphine?
How long does it typically take for pharmacodynamic tolerance to develop with analgesic doses of morphine?
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Which effect of opioids does not develop tolerance?
Which effect of opioids does not develop tolerance?
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What leads to physical dependence when using opioid agonists?
What leads to physical dependence when using opioid agonists?
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The development of physical dependence on morphine typically requires how many days?
The development of physical dependence on morphine typically requires how many days?
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What is cross-tolerance when discussing opioid use?
What is cross-tolerance when discussing opioid use?
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Which opioid is least likely to provoke significant reflex coughing?
Which opioid is least likely to provoke significant reflex coughing?
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Which symptom is NOT commonly associated with opioid withdrawal?
Which symptom is NOT commonly associated with opioid withdrawal?
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Study Notes
Opioid Receptors
- Opioid receptors are classified as μ, δ, and κ receptors.
- μ receptors are primarily responsible for supraspinal and spinal analgesia.
- κ receptors inhibit neurotransmitter release via N-type calcium channels.
- δ receptors respond to enkephalins and may modulate the activity of μ receptors.
Clinical Applications of Opioids
- Opioids are widely used for pain management, anesthesia, and sedation.
- Opioids may induce respiratory depression, especially at high doses.
- Opioids may trigger coughing, particularly with fentanyl, sufentanil, and alfentanil.
- Opioids can lead to pharmacodynamic tolerance and physical dependence.
Opioid-induced Respiratory Depression
- Opioids depress ventilation, leading to decreased responsiveness to carbon dioxide.
- This is characterized by an increase in resting arterial partial pressure of CO2 and a rightward shift in the carbon dioxide response curve.
- High doses of opioids may cause apnea, but individuals remain conscious and able to initiate a breath on demand.
- Opioid-induced respiratory depression is a major cause of opioid overdose mortality.
Opioid Tolerance and Dependence
- Tolerance develops to most effects of opioids, including analgesic, euphoric, sedative, and ventilatory effects.
- Physical dependence occurs with frequent opioid use and leads to withdrawal symptoms upon discontinuation.
- Opioid withdrawal symptoms include yawning, diaphoresis, lacrimation, coryza, insomnia, restlessness, abdominal cramps, nausea, vomiting, and diarrhea.
Opioid Pharmacokinetics
- Fentanyl, sufentanil, alfentanil, and remifentanil are widely used synthetic opioids.
- There are significant differences in potency and duration of action among these drugs.
- Opioid agonists are typically chiral molecules, with levorotatory isomers being biologically active.
Cardiovascular Effects of Opioids
- Opioids can induce tachycardia and hypertension through sympathetic nervous system and renin-angiotensin axis activation.
- High doses of opioids may reduce the likelihood of these cardiovascular responses.
- Combination of opioids with other anesthetics, such as nitrous oxide or benzodiazepines, may result in cardiovascular depression.
Protective Effects of Opioids on the Myocardium
- Opioids, particularly through σ and κ receptors, enhance the myocardial resistance to oxidative and ischemic stresses.
Other Relevant Information
- σ receptors were once considered opioid receptors, but now recognized for their involvement in cell signaling, metabolic regulation, and apoptosis.
- β-arrestins play a role in opioid-induced ventilatory depression and receptor desensitization.
- Lowering the pKa of an opioid compound could enhance its activity in areas of reduced pH, such as inflammation.
- Opioid agonist-antagonists primarily act on κ receptors.
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Description
Explore the functions and classifications of opioid receptors, including μ, δ, and κ types. Learn about the clinical uses of opioids in pain management and their potential for respiratory depression and dependence. This quiz covers essential aspects of opioid pharmacology.
