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30 Cards in this Set
- Front
- Back
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What is the endogenous agonist to the kappa opioid receptor?
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dynorphin
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What is the endogenous agonist to the delta opioid receptor
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leu-enkephalin
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where are opioid receptors concentrated
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Dorsal horn ot spinal cord, Cortex, Midbrain, localized to some peripheral sites
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Difference between opioids and anesthetics?
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presynaptic inhibition of Ca2+ channels and post synaptic opening of K+ channels
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What are the CNS effects of opioids?
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Analgesia (not neurogenic pain)
Euphoria Sedation - no amnesia, REM changes Respiratory Depression Antitussive Miosis Nausea and Vomiting - worse with Vestibular stimulation Muscle Rigidity |
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Peripheral effects of opioids?
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Decreased GI motility - constipation
Reduced Cardiac Preload - hypotension Urinary Retention - ADH release Reduced Uterine Tone Reduced Pulmonary Edema |
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Opioid overdose effects?
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respiratory depression. naloxone as antidote
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Morphine use?
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IV or oral- decrased bioavailability w/ 1st pass effect
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Morphine pharmacokinetics?
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hydrophilic: slow onset, long duration. Hepatic (glucuronidation) metabilism then renal clearence. Morphine-3-glucouronide and more potent morphine-6-glucuronide accumulate in renal failure. M3G produces seizures.
M3G/M6G - vasodilation, increases intrecranial pressure, immunosuppression, morphine itch. |
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C/I for Morphine?
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Bronchial asthma, pulmonary disease, head injury, EtOH use.
Pregnancy - RDS in fetus at high dose + fetal addiction |
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What are the 2 morphine derivatives w/ greater efficacy?
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Hydromorphone (Dilaudid) & oxymorphone (Numorphan)
Oxymorphone has less antitussive properties |
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Whats up with Methadone?
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Pure mu agonist. longer duration of action with less withdrawl.
interaction w/ TCAs&BDZs - alter metabolism |
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Action of Meperidine
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(Demerol) Less potent than morphine. Rapid onset. less-antitussive and constipation.
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PK of Meperidine?
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metabolite - meperidinic acid (CNS excitatory). does not inhibit uterine contraction nor prolong labor but crosses placenta and goes w/ milk. inhibits seratonin uptake ... seratonin syndrome w/ SSRIs
Pro-convulsant Seziures w/ selegiline and any MAOI/TCA |
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Fentanyl?
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Rapid onset via IV, short term, metabolized in blood not liver. Peak respiratory depression within 5 min.
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Properties of codeine
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12x less effective than morphine. antitussive but throught non mu mechanism. less addictive than morphine.
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Properties of oxycodone
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less potent than morphine. potent antitussive - not for asthmatics (OxyContin)
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Properties of hydrocodone
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less potnent than morphine. can be combined w/ ibuprofen as Vicoprofen. (Vicodin)
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Properties of Tramadol
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weak partial mu agonist. enhances 5HT trasmission. blocks NE uptake. do not combine w/ SSRIs = seratonin syndrome
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Properties of Propoxyphene
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50x less effective than codine. (Darvon)
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Properties of Loperamide and diphenoxylate
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mu agonists that work on the gut. little analgesic effect. treat diarrhea. watch out for toxic megacolon. (Imodium) and (Lomotil = atropine + diphenoxylate to stop abuse)
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Properties of Nalbuphine
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Kappa/Mu agonist as effective as morphine. bad WD symptoms. Hard to reverse w/ naloxone
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Pentazocine
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Kappa agonist w/ weak Mu agonism. can be used w/ naloxone to get analgesia w/o addiction. Used for pre-anethesia (no N/V). can cause seizures, CHF, psychosis. (Talwin)
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Butorphanol
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kappa agonist + weak mu agonist. incrases cardiac preload (CHF problems). has nasal prep (Stadol)
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Buprenorphine
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Mixed mu agonist/antagonist. Lipophilic. 25x more potent than morphine. not reversable by naloxone. for severe pain only. (Temgesic/Buprenex)
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use of naloxone
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reverse opioid action. can overshoot dose and cause WD. (Narcan)
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use of Naltrexone
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only blocks subjective effects of opioids. more potent than naloxone. used for abuse tx not OD. (Trexan)
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drugs that make up:
Empirin Vicoprofen Norcet Percodan Percocet Ultraset |
Empirin = Codeine+ASA
Vicoprofen = Hydrocodone+ibuprofen Norcet = Hydrocodone+acetaminophen Percodan = Oxycodone+ASA Percocet = Oxycodone+acetaminophen Ultraset = Tramadol+acetamiophen |
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Tx for neruropathic pain
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Anti convulsants: Carbamezepine, oxcarbazepine, lamotrigine.
Tramadol Gabapentin - non hepatic metabolism |
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Use for dextromethorphan
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antitussive (benylin, Vicks44)
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