1 / 18

Opiates

Opiates. Lesson 17. Opiates. Alkaloids from opium poppy Opium extract 0.5% codiene 20% morphine alter structure  heroin Opioids: synthetic analogs (texts) Major effects: Analgesia & Euphoria ~. Opiate Family. Large family of drugs neuropeptides morphine is prototype

Download Presentation

Opiates

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Opiates Lesson 17

  2. Opiates • Alkaloids • from opium poppy • Opium extract • 0.5% codiene • 20% morphine • alter structure  heroin • Opioids: synthetic analogs (texts) • Major effects: Analgesia & Euphoria ~

  3. Opiate Family • Large family of drugs • neuropeptides • morphine is prototype • Difference is potency • compare to morphine = 1 ~

  4. Relative Potency Opiate Potency Morphine 1 Methadone 1 Propoxyphene (Darvon) .05 Codeine .1 Meperidine (Demerol) .1 Oxycodone (Oxycontin, Percodan) .75 Heroin 3-4 Fentanyl 80 ~

  5. Pharmacokinetics • Route: sc, im, iv • p.o. not as effective • ion trapping • 1st pass metabolism • Significant brain levels: 30-60 min • immediate euphoria? • Conditioned effects ~

  6. Pharmacokinetics • Half-life: about 3 hrs • Duration of effects: 4-5 hrs • then withdrawal begins • Heroin: crosses BBB more easily • diacetylmorphine • biotransformed into morphine • Codiene: • 10% transformed to morphine ~

  7. Opiate Effects • Analgesia • Euphoria • Respiratory Depression • Narcosis • drowsiness ~

  8. Opiate Effects • Antitussive • inhibits coughing • Constipation • Impotence & reduced libido • Reduced aggression & social interaction • opioid role in social bonds • Alters food intake, BT, etc. ~

  9. Opioid Receptors • Areas Mapped (1970s) • Pain Pathways: • Periaqueductal Gray (PAG), • Dorsal Horn Spinal Cord • Also: • Hypothalamus • G. I. Tract, • Limbic System (VTA, Nucleus Accumbens) • Medulla ~

  10. Opioid Receptors • 2d messenger systems • Open K+ channels • hyperpolarization • Close Ca++ channels • decreased NT release • Inhibits adenylyl cyclase •  cAMP ~

  11. Opioid Receptors: Subtypes • m(mu) • m1 –  supraspinal & spinal analgesia • m2 –  respiration,  HR, euphoria • d (delta) • Modulates m analgesia, positive RFT • k (kappa) • spinal analgesia, pain perception • sedation, dysphoria, hallucinations • gut motility, body temperature ~

  12. Endorphins • Peptide Family: • Hormones, Neuromodulators & NTs • b -Endorphin • Met- & Leu-Enkephalin • Dynorphin ~

  13. Euphoria & Reward • Ventral Tegmental Area (VTA) • opioid neurons • dopamine neurons • GABA neurons? • hypothesized • GABA inhibits DA neurons • Opioids inhibit GABA neurons ~

  14. Opioid - GABA - VTA Nucleus Accumbens DA

  15. Other Opioid-Mediated Behaviors • Social Bond Formation • Various abnormal behaviors • Schizophrenia • Infantile Autism • Self-Mutilation ~

  16. Opiate Problems • High Dependence Liability • Positive & Negative Reinforcer • Withdrawal Symptoms • Tolerance & Cross Tolerance • Different rates for various effects • Euphoria: fast • Respiratory depression: slow ~

  17. Opiate Dependence: Treatment • 2007 National Survey on Drug Use and Health: heroin use / oxycodone • past year: 366, 000 / 1.4 million • past month 153,000 / 369,000 • Methadone Treatment • taken p.o. • half-life about 36 hrs •  euphoria & blocks withdrawal • develop methadone dependence ~

  18. Opiate Dependence: Treatment • LAAM: L-alpha-acetylmethadol • (Orlaam) • half-life 2-6 days • slightly more treatment dropouts • not recommended for women of child-bearing age • *Buprenorphine (Subutex) •  craving • *Buprenorphine + naloxone (Suboxone) •  craving & rewarding effects ~

More Related