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37 Cards in this Set
- Front
- Back
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What are the endogenous opioid peptides?
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Enkephalins, Endorphins, Dynorphins
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What are the opioid receptors? What does activation of the receptors cause?
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Mu, kappa, delta
Activation causes: -Inhibition of adenylyl cyclase -Activation of K+ current (outward) -Suppression of Ca2+ current (inward) |
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Name the different opioid agonist congeners.
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Morphine, Meperidine, Fentanyl, Methadone
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What are the opioid mixed agonist-antagonists?
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Pentazocine, Nalbuphine, Butorphanol, Buprenorphine
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What are the opioid antagonists?
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Naloxone, Naltrexone, Nalmefene.
(opioid antagonists = Nal-) |
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How does morphine produce its analgesic effect?
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1. Inhibits ascending pain transmission from the periphery.
2. Activated descending inhibitory pain pathway from the brainstem. |
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Where does morphine predominately act upon in the pain pathway?
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Morphine predominately acts on the spinal cord (70%), followed by the brain (25%), then the receptors at 5%
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What are the major pharmacological effects of opiates?
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Analgesia
Respiratory depression Constipation and decrease micturation. |
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What are the effects of morphine?
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Depressed respiration --> death
Depressed cough reflex (dextromethorphan/codeine) Depressed temperature regulating center CTZ stimulated --> emesis Stimulated EW nucleus (miosis) Truncal muscle rigidity Convulsions Neuroendocrine: Decreased FSH & LH Decreased testosterone Increased prolactin Supressed immune system CVS: Hypotension, vasodilation Increased release of histamine Depressed vasomotor center Decreased blood vessel tone For angina: decreased PL, decreased chronotropic For dyspnea (due to LVF): decreased AL & PL GIT: Increased gastric emptying time Decreased intestinal secretion Spasm of anal & ileocecal sphinters Constipation Sphincter of Oddi contricted --> biliary colic Urinary retention Prolonged labor (phew!) |
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What are teh pharmacokinetics of morphine?
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Significant FIRST PASS metabolism PO so, IV, SC, epidural & intrathecal require less
Morphine converted to morphine-6-glucuronide which is the active metabolite Duration of action ~6 hours Contraindicated in neonates b/c they have low conjugation capacity |
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What are some of the S & S of acute opiod toxicity?
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Pin-point pupils
Respiratory depression Stupor & coma Urinary retention Body temperature decrease Increased intracranial tension |
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Are opioids tolerated?
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Most actions of opioids are tolerated EXCEPT in the Eye & GIT
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Is there any dependence to opioids?
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Withdrawal syndromes:
Rhinorrhea, sweating, yawning & diarrhea |
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What are the acute actions to opioids?
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Analgesia
Respiratory depression Euphoria Relaxation & sleep Tranquilization Decreased BP Constipation Pupillary constriction Hypothermia Drying of secretions Reduced libido Flushed and warm skin |
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What are the withdrawal signs of opioids?
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Pain & irritability
Hyperventilation Dysphoria & depression Restlessness & insomnia Fearfulness & hostility Increased BP Diarrhea Pupillary dilation Hyperthermia Lacrimation, runny nose Spontaneous ejaculation Chilliness & "goosebumps" |
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What are the precautions & contraindications?
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Infants & Elderly
Bronchial asthma Head injury Undiagnosed abdominal pain Pregnancy |
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Name the morphine congeners
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Hydromorphone (Dilaudid)
Oxymorphone (Numorphan) Codeine, Hydrocodone, Oxycodone Tramadol Heroin |
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What is codeine?
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Codeine is a morphine congener, a methyl morphine
Less potent & less efficacious than morphine as an analgesic More selective cough suppressant in low doses Good oral bioavailability Abuse liability is low Used w/APAP or ASA |
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What is Tramadol (Ultram)?
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Tramadol is a morphine congener
Centrally acting analgesic Inhibits reuptake of NA & 5-HT Analgesic action partially reversed by naloxone Less respiratory depression, constipation & sedation Seizures are most common side effect 100 mg Tramadol = 10 mg Morphine |
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what is heroin?
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Heroin is a morphine congener
Three times more potent than morphine, more lipid soluble More euphoria & HIGHLY addicting (Think "Transpotting") |
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What is oxycodone?
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Morphine congener
Orally active Used in combination w/APAP (Percocet) or ASA (Percodan) Abuse liability present |
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What is meperidine (Demerol)?
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Morphine congener
Atropine like Analgesic efficacy & respiratory depression equals morphine Does not suppress cough Does not produce miosis & GIT spasm or biliary colic Can be used in obstetrics, short acting, doesn't prolong labor May increase HR (anti-cholinergic action) Shorter duration of action than morphine Not used w/MAOIs - convulsions & coma Potential to cause dependence Used for diarrhea: Diphenoxylate Loperamide - doesn't cross BBB |
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What is fentanyl (Duragesic)?
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Morphine congener
100xs more potent than morphine - analgesic & respiratory depression Rapid onset, short duration Transdermal patches, lozenges available Fentanyl-Droperidol used for neuroleptanalgesia Muscle rigidity occurs as adverse effect Fentanyl congeners: Alfentanil - less potent, rapid acting Sufentanil - 5xs more potent than fentanyl Remifentanil - ultra short acting, similar potency, no accumulation, context-sensitive half-life at 4 minutes after 4 hour infusion |
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What is methadone (Dolophine)?
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Morphine congener
Mu agonist Analgesic & respiratory depression similar to morphine High oral bioavailability Half life is ~24 hours Tolerance and dependence develops slowly Used in substitution therapy for opioid withdrawal syndrome Levo-alpha acetyl methadol (LAAM) - useful in treatment of withdrawal syndrome of opioids Administered 3xs/week, preferred b/c of stabilizing effect & smooth action |
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The endogenous opioid system has what roles?
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Sensory role - pain
Modulatory role - GIT & endocrine Emotional role - rewarding & addicting properties Cognitive role - learning & memory |
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What is propoxyphene (Darvon)?
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Methadone congener
Weak mu agonist Dextro-propoxyphene is an analgesic Used w/APAP (Darvocet N) Cardiotoxic in high doses |
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So, what are the therapeutic uses of opioids?
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Analgesic
Balance anesthesia & neuroleptanalgesia Dyspnea due to acute LVF Cough - dextromethorphan/codeine Diarrhea - loperamide |
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What are mixed agonist-antagonist effects?
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Effects depend on previous exposure to opioids
Naive individuals, relieve pain Opioids dependence, precipitate withdrawal syndrome Cause less respiratory depression than morphine Less dependence & abuse liability |
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What is pentazocine (Talwin)?
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Opioid mixed agonist-antagonist
Mu partial agonist & kappa agonist Analgesia is mainly spinal (kappa) Tachycardia & rise in BP - sympathetic stimulation More likely to cause hallucinations Tolerance & dependence develops on repeated use |
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What is butorphanol (Stadol)?
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Mu partial agonist & kappa agonist
20xs more potent analgesic than pentazocine Hemodynamic changes similar to pentazocine Nasal prep available for migraine Parenterally for moderate to severe pain management, supplement for anesthesia, labor pains More effective in reducing pain in women > men Analgesia 5xs more than morphine Kappa agonist activity of butorphanol increases pulmonary arterial pressure and cardiac work |
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What is nalbuphine (Nubain)?
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Mu antagonist & kappa agonist
Doesn't cause cardiac stimulation Used for post-op pain & labor |
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What is buprenorphine (Temgesic/Buprenex)?
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Mu partial agonist & kappa antagonist
Long acting - tight binding to receptors Naloxone partially reverses effects & doesn't precipitate withdrawal rxn b/c of tight binding to receptors Long acting w/half life ~37 hrs SL/TD available Used in post-op pain & opioids dependence (even if morphine is given, there will be no effects of morphine) |
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What are opioid antagonists used primarily for?
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For physiological addiction or OD?
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What is naloxone (Narcan)?
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Opioid antagonist, competitive antagonist of all opioid receptors
Half life 1-3 hours Inactive orally - high first pass metabolism Actions of buprenorphine & tramadol not fully reversed by naloxone Blocks endogenous opioid peptides Used in the treatment of opioid OD & dependence |
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What is naltrexone (ReVia)?
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Pure antagonist
More potent than Naloxone Orally active Long duration of action (1-2 days) Used to treat opioid dependence Half life ~10hours |
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What is opioids detoxification?
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Rapid opiate detox is a procedure which remove active opiates from teh body through administration of naltrexone, while a patient is under general anesthesia
Lasts ~4-6 hours, produces relatively little withdrawal symptoms allowing for a more comfortable & shorter recovery time For many, only way to endure painful withdrawal symptoms |
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Rapid detox treatment beneficial for whom?
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Beneficial for:
Opioid dependent individuals looking for aternatives to methadone treatment Methadone patients not able to kick the habit Pts who attempted detox on own or in clinical setting, but was unsuccessful |
