Chapter 11 THC

1
Chapter 11THC

• Presented by Kristal Jenkins, Sherri Notestine,
  Heather Risk

2
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.

3
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.

4
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.

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Side-effects of THC

• Sedation
• altered motor coordination
• impaired cognition
• reduced short-term memory
• Smoking during pregnancy can cause damage to the
  fetus.

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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.

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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.

8
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.

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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.

10
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.

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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.

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Institute of Medicines 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.

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Institute of Medicines 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.

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Institute of Medicines 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.