Stimulants

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Chapter 8

• Stimulants

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From your perspective, how would you deal with
the following situations? a. Your best friend
has developed a fondness for cocaine. She
frequently asks to borrow money from you to buy
cocaine.
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You notice that a friend is doing poorly in
school, associates with people who sell drugs,
and is becoming less sociable.
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c. Because you can no longer lend your best
friend money to buy cocaine, he is engaging in
illegal activities, that is, stealing and selling
drugs.
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d. Your girlfriend has been reading magazine
stories about cocaine. She becomes curious about
the effects of cocaine and would like to try it.
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e. Your boyfriend is 30 pounds overweight. He
has tried diets and aerobics but nothing seems to
help. He has decided to try amphetamines as his
next alternative.
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History of Cocaine

• Coca (5,000 B.C.)
• Cocaine was isolated to produce local anesthesia
  (1860s)
• Sigmund Freud experimented for psychiatric uses
  (1880s)
• http//www.cocaineaddiction.com/cocaine_timeline.h
  tml. A history of cocaine.
• Legal regulations - 1857-1914
• Crack -smokeable form (1970s)

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Drugs in the Media

• www.cnn.com/HEALTH/9706/02/nfm.supplement/, CNN
  Interactive FDA Wants Warning Labels for Some
  Herbal Supplements
• http//my.webmd.com/content/article/1728.60787,
  WebMD Shedding Light on Herbal Supplements.

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Pharmacology of Cocaine

• Coca paste (coca leaves mixed with organic
  solvent)
• Cocaine hydrochloride (paste salt mixes easily
  with water)
• Freebase (volatile organic solvent , vapors are
  inhaled)

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Mechanism of Action

• Cocaine blocks the reuptake of dopamine,
  norepinephrine, and serotonin and GABA
• Causes prolonged effect on neurotransmitters
• Behavioral effects based upon the interaction of
  multiple neurotransmitters

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Absorption and Elimination

• Chewing/sucking leaves absorbed into mucous
  membranes (slower)
• Snorting into nasal mucosa (quicker)
• IV bloodstream (rapid and brief)
• Smoking crack is less invasive and produces
  faster effects than IV
• Metabolized by enzymes in blood and liver
  (half-life 1 hour)

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Beneficial Uses

• Local anesthesia - Procaine is as effective as
  cocaine but lacks the potential for misuse.
• Increases energy
• Increases well-being (short and brief)
• http//www.druglibrary.org/schaffer/hemp/medical/m
  eduse.htmMedical uses of illicit drugs.

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Causes for Concern

• Acute toxicity - varies greatly among
  individuals.
• Chronic toxicity - binge can lead to a paranoid
  psychosis

• Dependence potential - Laboratory animals will
  self-administer to the point of death.
• Reproductive effects - Cocaine use increases risk
  of miscarriage and torn placenta.

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Cocaine Treatment

• Beta-adrenergic blocking drugs for irregular
  heart rate and blood pressure
• Haldol controls psychotic symptoms
• Anti-depressant drug desipramine helps promote
  abstinence

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Cocaine Treatment, contd

• Behavioral approaches
• Contingency contracting
• Relapse prevention
• Group support

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Early Uses of Amphetamines

• Ma huang (ephedra) used for centuries - Chinese
  Tea
• Amphetamines patented in 1932 to treat Asthma
• Narcolepsy treatment and appetite depressant
  (late 1930s)
• WWII elimination of drowsiness and repletion of
  the spirit concept

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Early Uses of Amphetamines, contd

• Speed term used (1960s) to IV users combining
  with heroin (San Francisco)
• Look-a-likes (1980s) OTC versions
• Crystal meth, ice methamphetamine
  hydrochloride crystals (late 1980s) - home labs

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Chemical Structure

• The amphetamine molecule is similar to that of
  dopamine and norepinephrine.
• Figure 8-2 shows similarities between
  amphetamines and related drugs
• Methyl group allows molecule to pass through
  blood-brain barrier more easily increasing
  potency
• PPAs in Cold Meds decongestant, cannot pass
  through blood-brain barrier decreasing CNS effect

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Mechanism of Action

• Stimulant has two effect on catecholamine
  synapses
• Leakage of catecholamines into the synapse.
• Occupies the reuptake mechanism causing a longer
  duration
• Stimulation of norepinephrine alert effects

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Mechanism of Action, contd

• Stimulation of dopamine pathways create euphoria
  and increased motor activity
• Increased doses produce repetitive movements that
  could lead to psychotic reactions

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Absorption and Elimination

• Orally
• IV injection
• Half-life for amphetamines is 10-12 hours vs. 4-5
  hours for methamphetamines
• Elimination occurs within two days of last dose

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Beneficial Uses

• Depression treatment (1950s and 60s)
• Weight control-supreses appetite
• Fatigue

• Narcolepsy - day sleeping
• Hyperactive children - attention deficit
• Smart pills - increase arousal
• Athletics - slight improvement in reaction time,
  speed
• www.prn2.usm.my/mainsite/bulletin/sun/1996/sun27.h
  tml. The history of drug abuse in sports.

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Causes for Concern

• Acute toxicity - Violence and aggression
• Chronic toxicity - can develop a paranoid
  psychosis.
• Dependence potential - powerful withdrawal
  symptoms
• Nearly 5 percent of high school seniors have
  reported amphetamine use.

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Chapter 8

• Stimulants