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Definition
Phenanthrene (strong agonist)
MOA: natural opioid, affects MOR
PK: hydrophilic, poor lipid solubility, ½ life=2hrs, lower absorption and CNS entry; oral admin-1st pass metabolism, 25% bioavailabilty, less effective than paraenteral but easier
Metabolism: CYP450 -> morphine-3 and morphine-6 glucuronide (2x potent), sustained release formulation used for 8-12hr analgesia
Effects: analgesia, sedation, euphoria (sometimes dysphoria)
USE: MI pain (anxiolytic and sedating), epidural anesthesia (long-lasting), cancer pain
SE: respiratory depression -> respiratory arrest, high potential for abuse, antitussive, prolong labor, miosis
DI: MAOI, alcohol |
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Definition
Phenylpiperidine (strong agonist)
MOA: very potent MOR agonist (~100x morphine)
Less nausea, more muscle rigidity
PK: highly lipophilic, faster absorption and CNS entry
Multiple routes available: paraenteral (I.V., epidural, intrathecal; oral mucosa (lozenge lollipop); transdermal patches for 72 hr analgesia
USE: anesthetic (combined with droperidol)-greater hemodynamic stability and no histamine release
Derivatives: sufentanil, alfentanil -> anesthetic adjuvants, epidural
DI: several (aprepitant, antibiotics, diltazem, verapamil) |
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Definition
Phenylheptalamine (strong agonist)
MOA: potent MOR agonist, racemic mix also blocks NMDAR
USE: analgesia, instead of heroin addiction
PK: better bioavailability than morphine, long-lasting; long ½ life=25-52hrs (strong binding to protein -> accumulation, maintained low conc. when discontinued)
Milder, but more prolonged withdrawal than morphine
If taken as prescribed, minimal euphoria and prevents withdrawal SEs
Risk of opioid OD if taken with heroin |
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Definition
Phenylpiperidine (strong agonist)
MOA: MOR agonist
PK: less potent and shorter acting than morphine-faster onset (~10min) and duration (1.5-3hr)
Unusual profile compared to morphine-does not prolong labor, not antitussive, less constipation
Not recommended for chronic pain (>48hrs) -> toxic metabolite normeperidine can accumulate -> dysphoria, irritability, tremors, myoclonus, seizures
DI: MAOIs -> cerebral edema (5-HT syndrome)
Anti-muscarinic activity can lead to tachycardia -> not used for MI |
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Definition
Phenanthrene (mild to moderate agonist)
MOA: weak MOR, but metabolized to morphine (~10% of population have polymorphims of CYP2D6 -> do not efficiently convert codeine to morphine
PK: excellent oral bioavailabilty (~60%) -> less 1st pass metabolism
USE: mild-moderate pain, antitussive; doses exert minimal SEs, histamine release -> itching, usually combo w/ acetaminophen or aspirin for pain relief |
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Definition
Phenylheptylamine (mild to moderate agonist)
MOA: MOR agonist chemically related to methadone
USE: mild-moderate pain
Orally less potent than codeine-combined with aspirin, effective analgesia; sometimes used because of overconcern of abuse liability of codeine
Adverse interactions with alcohol and sedatives can be fatal
Irritant when IV or subcutaneous; buildup in body -> toxic psychosis, pulmonary edema, cardiotoxicity
Reduced use because other equally efficacious medications available without adverse interactions
Risk of fatal overdose |
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Definition
Phenanthrene (mild to moderate agonist)
MOA: MOR receptor agonist
USE: Mild-moderate pain
PK: better oral availability than morphine; used in lower doses in combo w/ aspirin or acetaminophen; synergistic pain relief (Percodan or Percocet)
Metabolism by CYP450, CYP2D6 system – potential drug interactions
Widespread abuse of sustained release OxyContin |
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Definition
Benzomorphan (mixed agonist-antagonist and partial agonist)
MOA: KOR agonist, weak MOR antagonist/partial agonist
USE: moderate pain -> only for pts not using other opioids, ceiling effects for analgesia and respiratory depression
Formulated with naloxone (IV -> prevents euphoria, oral -> doesn’t block)
Less nausea than morphine
SE: sedation, sweating, dizziness, psychomimetic effects, anxiety, increase HR/BP |
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Definition
Morphinan (mixed agonist-antagonist and partial agonist)
MOA: similar to pentazocine, 30x more potent than pentazocine as an agonist at KOR and 20x more potent as an analgesic
USE: moderate-severe pain
Better for acute than chronic pain |
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Definition
Phenanthrene (mixed agonist-antagonists and partial agonists)
Similar to naloxone
When admin paraenterally -> eqipotent to morphine and 5x more potent than pentazocine
Fewer psychotomimetic effects than pentazocine, greater MOR antagonist activity |
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Definition
Phenanthrene (antagonist)
Fast onset (min) and offset (1-2hr)
Multiple injections may be needed to treat OD
Minimal oral bioavailabilty-almost complete 1st pass metabolism
If given alone to opioid-naïve person -> little effect |
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Definition
Phenanthrene (antagonist)
More potent than naloxone
Longer duration of action (1/2 life=10 hrs, effect for days)
Greater oral bioavail than naloxone
Helpful in drug addiction -> alcohol dependence, reduced heroin-seeking |
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Definition
(strong agonist)
similar to codeine but with lower affinity for opioid receptors
MOA: unique dual mechanism of pain relief- weak MOR agonist and monoaminergic reuptake blockade
less potential for abuse or respiratory depression
post-operative analgesic equivalent to codeine
cancer pain management-tramadol is moderate agent |
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