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Questions and Answers
Which term encompasses all compounds related to opium?
Which term encompasses all compounds related to opium?
What are endogenous opioids primarily classified as?
What are endogenous opioids primarily classified as?
Which of the following drugs would be classified as an opioid analgesic?
Which of the following drugs would be classified as an opioid analgesic?
What is the primary function of analgesics?
What is the primary function of analgesics?
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Which component of the drug classification specifically refers to morphine-like substances?
Which component of the drug classification specifically refers to morphine-like substances?
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Which of the following drugs is considered a strong agonist?
Which of the following drugs is considered a strong agonist?
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What is the primary function of µ receptors in opioid action?
What is the primary function of µ receptors in opioid action?
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Which classification includes drugs that activate one receptor subtype and act as antagonists at another?
Which classification includes drugs that activate one receptor subtype and act as antagonists at another?
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Which of the following is NOT a characteristic of δ receptors?
Which of the following is NOT a characteristic of δ receptors?
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What occurs when presynaptic opioid receptors are activated?
What occurs when presynaptic opioid receptors are activated?
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Which of the following is considered a mild to moderate opioid agonist?
Which of the following is considered a mild to moderate opioid agonist?
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Which type of opioid receptor is responsible for spinal analgesia?
Which type of opioid receptor is responsible for spinal analgesia?
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Which antagonist is used for reversing opioid overdose?
Which antagonist is used for reversing opioid overdose?
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What is a typical cardiac effect produced by opioids?
What is a typical cardiac effect produced by opioids?
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What is a primary benefit of using opioids as adjuvants in anesthesia?
What is a primary benefit of using opioids as adjuvants in anesthesia?
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Which of the following effects can occur due to high doses of opioids?
Which of the following effects can occur due to high doses of opioids?
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What effect do opioids have on miosis?
What effect do opioids have on miosis?
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Which opioid is specifically indicated for the treatment of narcotic dependence?
Which opioid is specifically indicated for the treatment of narcotic dependence?
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How do opioids affect gastrointestinal (GIT) motility?
How do opioids affect gastrointestinal (GIT) motility?
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What is a common adverse effect associated with opioid use?
What is a common adverse effect associated with opioid use?
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Which of the following is a significant immune effect of opioids?
Which of the following is a significant immune effect of opioids?
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What route of administration is favored for regional analgesia due to fewer adverse effects?
What route of administration is favored for regional analgesia due to fewer adverse effects?
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What is the effect of therapeutic doses of morphine on labor?
What is the effect of therapeutic doses of morphine on labor?
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Which preparation is commonly used for chronic pain management?
Which preparation is commonly used for chronic pain management?
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Which statement about tolerance and dependence in opioid use is correct?
Which statement about tolerance and dependence in opioid use is correct?
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Which condition is morphine NOT typically used to treat?
Which condition is morphine NOT typically used to treat?
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Which mechanism underlies opioid-induced bronchoconstriction?
Which mechanism underlies opioid-induced bronchoconstriction?
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What is a consistent physical finding in patients with morphine addiction?
What is a consistent physical finding in patients with morphine addiction?
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Which of the following opioids is primarily known for its antidiarrheal properties?
Which of the following opioids is primarily known for its antidiarrheal properties?
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Which of the following conditions is a contraindication for the use of morphine?
Which of the following conditions is a contraindication for the use of morphine?
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What is a reason for why morphine should not be given as a first choice in patients with pulmonary disease?
What is a reason for why morphine should not be given as a first choice in patients with pulmonary disease?
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Why should corticosteroids be discontinued prior to the insertion of an epidural catheter for morphine administration?
Why should corticosteroids be discontinued prior to the insertion of an epidural catheter for morphine administration?
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What effect can morphine have on patients with senile enlarged prostate?
What effect can morphine have on patients with senile enlarged prostate?
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In patients with which condition might opioids have prolonged and exaggerated effects?
In patients with which condition might opioids have prolonged and exaggerated effects?
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Which of the following symptoms is a characteristic of morphine overdose?
Which of the following symptoms is a characteristic of morphine overdose?
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Why is morphine contraindicated in patients with undiagnosed acute abdominal pain?
Why is morphine contraindicated in patients with undiagnosed acute abdominal pain?
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What is a common effect of chronic administration of opioids?
What is a common effect of chronic administration of opioids?
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Study Notes
Analgesics: Opioid and Non-Opioid
- Analgesics relieve pain by acting on the central nervous system (CNS) or peripheral pain mechanisms without altering consciousness
- Opioids are drugs with morphine-like activity
- Opiates are drugs derived from the opium plant, including morphine, codeine, and thebaine, and their semisynthetic derivatives
- Narcotics induce sleep, but the term is now often associated with opioids
- Endogenous opioids include endorphins, enkephalins, and dynorphins
- Opium is derived from the juice of the opium poppy, Papaver somniferum
Opioid Classification
- Strong agonists include: morphine, hydromorphone, oxymorphone, heroin, methadone, meperidine, fentanyl, sufentanil, and alfentanil
- Mild-moderate/low agonists include: codeine, dihydrocodeine, oxycodone, hydrocodone, propoxyphene, diphenoxylate, and loperamide
- Mixed agonist/antagonist and partial agonists include: butorphanol, nalbuphine, and pentazocine
- Antagonists include: naloxone and naltrexone
Opioid Receptors
- Opioid receptors are G-protein linked and include µ (mu), δ (delta), and κ (kappa) subtypes
- These receptors are distributed throughout the brain and spinal cord
- µ Receptors mediate most of the analgesic effects of opioids, as well as respiratory depression, euphoria, sedation, and dependence
- δ Receptor activation leads to analgesia but can also induce convulsions
- κ Receptors mediate spinal analgesia, miosis, sedation, and hallucinations
Cellular Mechanisms of Action
- Opioid drugs act by interacting with receptors for endogenous opioids
- Effects vary depending on the receptor subtype and if the drug acts as a full agonist, partial agonist, or antagonist
- Some drugs act as agonists at one receptor subtype and antagonists at another
- Activation of presynaptic opioid receptors inhibits Ca2+ influx and neurotransmitter release
Cardiovascular Effects
- Opioids induce bradycardia due to vagal stimulation and histamine release
- High doses decrease blood pressure (orthostatic hypotension) due to the inhibition of the vasomotor center and peripheral vasodilation caused by histamine release
Medullary Effects
- Opioids suppress cough by inhibiting the cough center
- High doses of opioids inhibit the respiratory center, which can lead to fatal respiratory depression
- Opioids stimulate the chemoreceptor trigger zone (CTZ), leading to vomiting
Miosis
- Opioids cause miosis (pupillary constriction)
- Severe miosis is indicative of toxic doses
- Pinpoint pupils (PPP) are a diagnostic sign of opioid use and abuse
Gastrointestinal Effects
- Opioids increase sphincter tone and decrease gastric motility, leading to constipation
- Decreased gastric motility can increase gastric emptying time and reduce the absorption of other drugs
- Opioids can constrict the urinary bladder wall, causing urinary urgency, and the urinary sphincter, leading to painful urine retention
- Opioids can also constrict the gallbladder wall and sphincter
Immune Function and Histamine
- Opioids induce histamine release, causing itching
- Opioids are immunosuppressive, affecting T-helper and T-suppressor cells
Uterus
- Opioids can prolong or delay labor
- Opioids cross the placental membrane
Bronchoconstriction
- Opioids induce bronchoconstriction via vagal stimulation and histamine release
Clinical Uses of Opioid Analgesics
- Analgesia for moderate to severe and chronic deep pain, such as acute myocardial infarction (MI), bone fractures, cancer, surgery, etc.
- Morphine with atropine is the drug of choice for treating myocardial infarction due to its bradycardiac and vasodilatory effects
- Morphine with atropine is used for severe colic
- Morphine is used for acute pulmonary edema (cardiac asthma)
- Opioids are used as adjuvants in anesthesia for sedation, anxiolytic effects, and to reduce the dose of anesthetics
- Opioids are used for regional (epidural) anesthesia to achieve long-lasting analgesia
Commonly Used Opioids
- Morphine, meperidine, oxycodone, and propoxyphene are used as analgesics
- Codeine is used as both an analgesic and an antitussive
- Methadone is used to treat narcotic dependence
- Loperamide, diphenoxylate, and opium tincture are used as antidiarrheals
- Heroin is highly abused and used by approximately 80% of narcotic abusers
Adverse Effects
- CNS: Tolerance and physical dependence (addiction) with prolonged use
- Tolerance develops to analgesic and euphoric effects but not to respiratory depression
- Opioids can increase intracranial pressure
- Opioids can cause respiratory depression
- Respiratory: Bronchoconstriction
- Cardiovascular: Postural hypotension
- Gastrointestinal: Nausea, vomiting, and constipation; Increased biliary tract pressure and biliary colic
- Genitourinary: Urine retention, especially in patients with enlarged prostate; Prolongation of labor
- Eye: Miosis is a consistent finding in morphine addiction
Contraindications of Opioids
- Hypersensitivity to opioids
- Bronchial asthma, as opioids can worsen respiratory symptoms
- Infection at the injection site for epidural use, as opioids can increase the risk of infection
- Head trauma, as opioids can mask neurological signs
- Pregnancy, as opioids can cross the placenta and affect the fetus
- Consumption of alcohol or barbiturates, as opioids can enhance the effects of these drugs
- Enlarged prostate, as opioids can cause urinary retention
- Impaired hepatic or renal function, as opioids can be metabolized and excreted by these organs
- Undiagnosed acute abdominal pain, as opioids can mask pain and interfere with diagnosis
- Hypotension and hypovolemia, as opioids can worsen these conditions
- Endocrine diseases, such as Addison's disease and hypothyroidism, as patients with these conditions can have exaggerated responses to opioids
Tolerance
- Tolerance develops to analgesic and euphoric effects after 10-14 days of continuous opioid administration.
- Chronic opioid administration decreases the production of endogenous endorphins and norepinephrine (NA).
- Sudden withdrawal leads to an immediate deficiency of endogenous opioids and a rebound increase in NA release.
Toxicity
- Opioid overdose characterized by: miosis (PPP), hypotension, respiratory depression, coma, and death
- Supportive treatment is necessary for opioid overdose.
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Description
This quiz explores the key concepts of analgesics, focusing on both opioid and non-opioid classifications. Learn about the mechanisms, classifications, and specific drugs involved in pain relief. Test your understanding of how these compounds interact with the central nervous system.
