Stimulants and cocaine

Question 1

Stimulant abuse in college students

Answer 1

• primary reason = study, stay awake,
• often in conjunction w/ other substance abuse (e.g. marijuana, alcohol, smoking, cocaine, ecstasy)
• felt that doing so was helpful
• higher rates in more competitive schools/regions, frats/sororities, males,
• substance use usually peaks in 3rd year then drops slightly in 4th yr of college
• Actually associated with decline in academic performance
• Source: diverted from ppl w/ prescriptions, “easy” to obtain
• high rate of students fake or exaggerate sx to get meds

Question 2

Stimulant abuse - health risks

Answer 2

• low perceived risk for taking these meds
• cardiovascular,
  
  • arrythmias, heart attack, stroke, hypertension
• psychiatric:
  
  • psychosis, delirium, mania, agitation, mood swings, anxiety, insomnia, depression
• intoxication:
  
  • euphoria, hypervigilance, anxiety, impaired judgement/functioning
• withdrawal:
  
  • fatigue, insomnia, more appetite
• drug-drug intx

Question 3

Cocaine powder vs crack cocaine

Answer 3

• cocaine powder = cocaine hydrochloride
  
  • injected (3 min to peak), snorted (30 min to peak)
  • injection gives rapid onset and high plasma levels
• crack cocaine (freebase) = cocaine w/o the chloride
  
  • turns it into a weak base
  • vaporizes at low temp – can be smoked
  • rapid onset, high plasma levels

Question 4

Cocaine - mechanisms of action

Answer 4

• blocks dopamine transporter by binding to it
• increases amount of dopamine in synapse
  
  • nucleus accumbens
• local anesthetic, vasoconstrictor, CNS stimulant

Question 5

Acute effects of cocaine

Answer 5

• euphoria
  
  • parallels the uptake and displacement of cocaine in striatum
  • as euphoria decreases –> re-dose
• pressured speech
• racing thoughts
• grandiosity
• increased HR and BP
• decreased appetite
• anxiety
• delusions

Question 6

Cocaine + other substance use

Answer 6

• Cocaine & alcohol
  
  • reduces anxiety from coming down from cocaine, psychoactive intermediate prolongs the high
• cocaine & heroin
  
  • enhances positive effects of both drugs
  • reduces unpleasant side effects of cocaine

Question 7

Toxicity of cocaine

Answer 7

• CNS:
  
  • seizures
  • stroke
• Cardiac:
  
  • chest pain, MI, cardiomyopathy, myocarditis
• Other:
  
  • rhabdomyolysis, high fevers, intestinal ischemia, perforated nasal septum, low birthweight, placental abruption, premature labor, (no effect on neurocognitive function)
• decreased blood flow due to vasoconstriction

Question 8

Process of addiction to cocaine

Answer 8

• leads to long-term sensitization –> increasing desire to use cocaine after several administrations (stronger cravings)
  
  • increased activity of AMPA receptors on dopaminergic neurons in the VTA causes increasing release of dopamine into the ncuelus accumbens
• Drug induced brain changes resulting in increased drug salience/increased intensity of cravings + drug induced changes that impair individuals ability to weight risks/benefits and resist impulses

Question 9

Cocaine and changes in brain activity

Answer 9

• drug induced decrease in frontal lobe activity especially w/ chronic use but present earlier on
• may be involved in development of addiction since frontal lobe is involved in impulse control

Question 10

Treatment

Answer 10

• early tx or tx post-relapse must be intensive
• structured therapy for 1+ yrs
  
  • individual drug counseling (w/ contingency management) worked best (esp from former drug users)
  • CBT also works well and has good long-term effects
• long-term, flexible tx needed
• very difficult to treat and maintain abstinence
• vouchers help in short term abstinence
• some meds in trials

Question 11

Meds for cocaine dependence

Answer 11

• Topiramate
  
  • glutamate antagonist – blocks AMPA receptor
  • GABAergic – increases transmission @ GABA A receptor, increases GABA levels
  • ** makes cocaine less appealing, prevents relapse, higher rates of post-trial abstinence, reduces use
• Modafinil
  
  • approved for epilepsy
  • blocks dopamine transporter
  • may reduce high from cocaine
  • ** reduces self-administration, good abstinence rates