Term
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Definition
• Mu agonist • MYDRIASIS
• Less potent than morphine (1/10)
• Shorter duration of action
• Better oral:parenteral ratio
• High doses more likely to produce excitation; tremors and seizures may occur due to accumulation of the metabolite
• Contraindicated with MAO inhibitors (seizures)
• Should be used with caution in asthmatic patients
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Term
| Propoxyphene (dextropropoxyphene, Darvon) |
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Definition
• Less selective mu agonist
• Orally effective but less potent than codeine
• Uses to produce analgesia similar to codeine
• Combined with aspirin for enhanced effect
• Excitatory in high doses
• Abuse liability like codeine
• Deaths from propoxyphene overdose: respiratory and circulatory collapse, pulmonary edema, cardiac arrhythmias, convulsions, coma.
• Respiratory depression from propoxyphene is antagonized by naloxone.
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Term
| Naltrexone (Trexan; ReVia) |
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Definition
• Also relatively "pure" antagonist
• More effective orally than naloxone due to slower metabolism (24-hour duration of action with moderate oral doses)
• Can cause hepatic toxicity (monitor liver function with chronic use to treat compulsive abuse; concomitant use with disulfiram not recommended; could have synergistic effects with ethanol)
• Will precipitate withdrawal; will block analgesic effect of opioids
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Term
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Definition
• Heroin substitutes acetyl groups on the phenolic and alcoholic OH (3,6 positions) to become diacetylmorphine). It is deacetylated in the body to acetylmorphine and morphine. - PURE AGONIST
- Most Lipophilic of all Opioid (crosses BB barrier)
- Opioid withdrawl is NOT fatal
- Withdrawl symptoms: mydriasis, diarrhea, vasoconstriction, dysphoria
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Term
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Definition
• Mu agonist
• Similar to morphine in action, duration and potency, when given parenterally
• High oral efficacy with resulting longer duration of action
• Methadone maintenance in opioid dependence. Addict is dependent upon methadone rather than morphine or heroin.
• Cumulation can occur due to binding to tissue proteins
• Side effects and toxicity similar to morphine
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Term
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Definition
• Weak antagonist or partial agonist at mu receptor; agonist at kappa receptor
• Specifically synthesized to find analgesic without abuse potential
• Has both agonist and antagonist properties
• Less potent than morphine
• Naloxone will antagonize the respiratory depression.
• Anxiety, nightmares and hallucinations with repeated high dose (kappa and/or sigma receptor).
• Abuse potential lower than codeine, but is compulsively abused. Type of dependence differs in some
respects from morphine.
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Term
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Definition
• Effective orally
• Often combined with aspirin for increased effectiveness
• Used extensively for antitussive action
• 10% demethylated to morphine (responsible for analgesic effect); mu agonist
• Excitatory effects in children and some adults
• Less potent than morphine
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Term
| Fentanyl (Sublimaze), Sufentanil (Sufenta), and Remifentanil (Ultiva) |
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Definition
• Mu Agonists
• High potency and short duration of action (due to high lipid solubility and redistribution)
• Used in anesthesia and postoperative analgesia; fentanyl is available in transdermal (patch) formulation for severe chronic pain
• Do not cause histamine release
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Term
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Definition
- Agonist- antagonist and Partial Agonist Drug (mixed)
- Drugs in this group are either competitive antagonists or partial agonists at the mu receptor and generally possess agonist activity at kappa receptors.
- Produces less respiratory depression in overdose (lower "ceiling") and less bile duct spasm
- Advantages= reduced abuse liability and reduction of some adverse effects while retaining strong analgesic
properties. - Disadvantages = most have more "psychotomimetic" activity (kappa and sigma receptor) and will precipitate
withdrawal in opioid-dependent person.
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