THC Sedative by liaoqinmei

VIEWS: 12 PAGES: 14

									        Chapter 11
           THC

 Presented by Kristal Jenkins,
Sherri Notestine, & Heather Risk
    THC Compared to Non-
     selective Depressants
   Until about 1990, marijuana was classified according
    to its behavioral effects, usually as a mild sedative-
    hypnotic agent, with effects similar to low doses of
    alcohol and the benzodiazepines. Unlike sedatives,
    however, higher doses of THC do not depress
    respiration and are not lethal. Little cross-tolerance
    occurs between THC and the sedative-hypnotics.
    THC also produces a unique spectrum of
    pharmacologic effects, including disruption in
    attention mechanisms, impairment of short-term
    memory, altered sensory awareness, analgesia,
    altered control of motor movements and postural
    control, and a possible immunosuppressive action.
THC Compared to Psychedelic
         Drugs
  THC does not have a similar chemical
   structure to that of psychedelic drugs.
   Also, much less sensory disorientation
   than psychedelic drugs.
  However, although infrequent, high
   doses do produce hallucinations and
   illusions in some users.
        The Half-life of THC
   The metabolism of THC itself is quite slow: an
    elimination half-life of about 30 hrs. is generally
    accepted, although some researchers report longer
    half-life. Therefore, THC can persist in the body for
    several days to about 2 weeks. Such a delay tends to
    prolong and intensify the activity of subsequently
    smoked marijuana, forming a type of “reverse
    tolerance” to the drug, where the persistent low
    levels are potentiated by subsequently smoked THC
    cigarettes.
    Side-effects of THC
 Sedation
 altered motor coordination
 impaired cognition
 reduced short-term memory
 Smoking during pregnancy can cause
  damage to the fetus.
Societal Concerns for Young
           Users
   Beginning use during early adolescence may lead to enduring
    effects on specific attentional functions in adulthood.
   Impaired ability to drive long after effects are not felt by user.
   Increased high-school drop out rate
   Increase in other problem behaviors
   Correlated with other educational, job, and psychosocial
    problems, but no causal inferences can be drawn.
   Increased likelihood of some form of substance abuse or
    dependence of other drugs.
        Dependence Issues
   Some researchers have found withdrawal symptoms
    of restlessness, irritability, agitation, anxiety,
    depression, reduced food intake, insomnia, nausea,
    and cramping, beginning 48 hrs. after cessation of
    marijuana use. However, people rarely meet the
    criteria for being dependent:
   1. Preoccupation with the acquisition of the drug.
   2. Compulsive use of the drug.
   3. Relapse to or recurrent use of the drug.
     Cannabinoid Receptors
   The cannabinoid receptor is a chain of 473
    amino acids with seven hydrophobic domains
    that extend through the cell membrane; each
    region is composed of one hydrophobic
    domain. When THC binds to its receptors, it
    activates G-proteins that act on various
    effectors including the second-messenger
    enzyme adenylate cyclase and both
    potassium and calcium ion channels.
     Cannabinoid Receptor
          Locations
   The hippocampus, cerebral cortex,
    cerebral cortex, cerebellum, and basal
    ganglia appear to be major loci of
    action of THC because these structures
    are involved in cognition, learning,
    memory, mood, and other higher
    intellectual functions, as well as motor
    functions.
              Treatment
   Marijuana, used alone, rarely results in
    dependence. Treatments such as
    psychotherapy can be appropriate for
    frequent users of marijuana, but this is not
    therapy for marijuana abuse; it is therapy for
    an underlying psychopathology (such as
    depression), one symptom of which is the use
    of cannabis.
          Therapeutic Uses
   THC and various derivatives such as Dronabinal
    (Marinol) have been used to treat nausea and
    vomiting associated with chemotherapy in cancer
    patients. Other potential uses of Dronabinal are to
    reduce the muscle spasms and pain of multiple
    sclerosis and reduce the intraocular pressure of
    glaucoma. Both marijuana and non-psychoactive
    synthetic cannabinoids effectively protect the brain
    from permanent injury following head trauma or
    stroke.
     Institute of Medicine’s
       Recommendations
   The Institute of Medicine concluded
    that cannabinoids have potential
    applicability for some human
    symptoms. They suggest that these
    components should be delivered by a
    mechanism other than inhaling smoke.
     Institute of Medicine’s
       Recommendations
   They also recommend:
   Research should continue into the
    physiological effects of synthetic and plant-
    derived cannabinoids and the natural function
    of cannabinoids found in the body.
   Clinical trials for symptom management
    should be conducted.
   Psychological effects of cannabinoids should
    be evaluated in clinical trials.
      Institute of Medicine’s
        Recommendations
   Studies to define the individual health risks of
    smoking marijuana should be conducted.
   Clinical trial of marijuana use should involve only
    short-term marijuana use and be conducted where
    there is reasonable expectations of efficacy and be
    approved by review boards.
   Short-term use of smoked marijuana should be used
    when all other medications have been proven to fail,
    symptoms can reasonably be expected to be relieved.

								
To top