13镇痛药Analgesics——山东大学药理学英文课件.ppt

Chapter 21  Analgesics Pain a. Acute pain (sharp pain), superficial pain, quick response of sudden onset, conducted by A nerve fibers b. Chronic pain (dull pain), more lingering and aching, conducted by C nerve fibers Opium Alkaloids Phenanthrenes morphine, codeine Benzylisoquimolines papaverine --has no analgesic effect --dilates the vessel 1803 Serturner isolated a pure active alkaline substance from opium . He proposed the name“morphine”for it after Morpheus. Pharmacological actions 1.CNS effects :principal effects analgesia euphoria sedation respiratory depression tolerance (5) Others ↓release of gonadotropin-releasing hormone (GnRH) ↓ release of corticotropin-releasing hormone(CRF) ↓concentration of luteinizing hormone (LH) ,follicle-stimulating hormone(FSH) ↓adrenocorticotropic hormone(ACTH) ↑prolactin release Pharmacological actions 2. SM Stimulating Gastrointestinal system Biliary tract Urinary Bronchia (4) Artificial hibernation pethidine chlorpromazine promethazine lytic cocktailⅠ 4. Adverse effects CNS excitatory symptoms muscle tremors, twitches, convulsion should be combined with anticonvulsive drugs when treat overdose poisoning (2) some symptoms like atropine Increased CNS depression, particularly respiratory depression Opioid analgesics MAOIs Tricyclic antidepressants chlorpromazine promethazine Sedative- hypnotics Absolute contraindication to pethidine , relative contraindication to other opioid analgesics , because of high incidence of hyperpyretic coma Drug – Drug interactions Methadone Characteristics: 1. analgesia: equal to morphine 2. give reliable effects orally, longer duration of action 3. tolerance and physical dependence more slowly 4. withdrawal signs attenuated but protra