Cocaine and Amphetamines Study Notes

Psychomotor Stimulants: Cocaine and the Amphetamines

Cocaine

  • Introduction to Cocaine

    • Cocaine is categorized under psychomotor stimulants, which are known for their ability to increase alertness, heighten arousal, and cause behavioral excitement.

    • Cocaine is an alkaloid extracted from the leaves of the Erythroxylon coca shrub, native to South America, particularly in the Andes Mountains.

    • Historical context: Chewing coca leaves has been practiced for over 5000 years, prominently in Incan civilization.

    • Initially discouraged by the Catholic Church due to concerns over its influence; however, it was later recognized for its energizing effects on workers in high-altitude mines.

Historical Use and Marketing

  • 19th Century Promotions

    • Various products contained cocaine for its stimulant properties:

    • Cocaine Toothache Drops (1885), marketed as an instant cure for dental pain priced at $0.15.

    • Coca-Cola (introduced in 1886), described as an "intellectual beverage" that combined caffeine and cocaine, marketed as an alternative to alcohol.

    • Sigmund Freud was a prominent advocate for cocaine use, recommending it for various ailments and claiming it was non-addictive.

Mechanism of Action

  • Cocaine has three primary pharmacological actions:

    • Acts as a local anesthetic by blocking voltage-gated sodium channels.

    • Functions as a vasoconstrictor by increasing endothelin production and decreasing nitric oxide production.

    • Acts as a psychostimulant that stimulates the central nervous system by interfering with dopamine pathways in the brain.

Pharmacokinetics

  • Absorption and Distribution:

    • Cocaine is rapidly absorbed across mucous membranes and rapidly penetrates the brain after administration, resulting in higher concentrations in the brain than in plasma.

  • Metabolism and Excretion:

    • The biological half-life is approximately 50 minutes, primarily metabolized by the enzyme butyrylcholinesterase in the liver.

    • Cocaine metabolites include:

    • Benzoylecgonine: A key metabolite utilized for drug testing, detectable in urine for up to 48 hours.

    • Cocaethylene: Formed when cocaine is used concurrently with alcohol; exhibits similar effects to cocaine but has a longer half-life.

Psychological and Physical Effects

  • Cocaine's effects include increased heart rate, blood pressure, and energy levels, with a peak euphoria lasting about 10-20 minutes, often followed by a "comedown" characterized by mild depression and fatigue.

  • High doses can lead to severe cardiovascular issues, paranoia, and psychotic behaviors indistinguishable from paranoid schizophrenia.

  • Cocaine addiction presents with tolerance and withdrawal symptoms, including severe depression and drug cravings.

Cocaine Addiction and Neurobiology

  • Dopamine Depletion Hypothesis:

    • Chronic cocaine use leads to depletion of dopamine (DA), resulting from overstimulation and leading to dysphoria during abstinence periods.

  • WHO Report Findings:

    • Cocaine use is widespread across demographics, with limited treatment access for recreational users.

    • Concerns include the risk of escalated use patterns and long-term negative consequences.

Manufacturing Process

  • Cocaine Extraction:

    • Coca leaves are mashed with sulfuric acid and processed through several chemical steps involving kerosene and lithium to produce cocaine base.

  • Final Production:

    • The resulting cocaine base is again processed into cocaine hydrochloride, the final product sold illicitly.

Variants of Cocaine

  • Crack Cocaine:

    • Derived from cocaine hydrochloride through chemical modifications allowing it to be smoked.

    • Produces a quicker euphoric rush, which fades rapidly contributing to a cycle of use and withdrawal.

Cocaine-Induced Risks

  • Health Risks:

    • Regular use can lead to significant cardiac damage and acute mental health crises. Effects during pregnancy can lead to congenital abnormalities and developmental difficulties in offspring.

  • Social Implications:

    • Cocaine use raises broader societal issues, such as unpredictability in behavior, potential violence, and associated economic costs.

Amphetamine

  • Classification:

    • Amphetamines are also psychomotor stimulants with sympathomimetic effects on the CNS and autonomic nervous system.

  • Structure and Types:

    • Amphetamines include dextroamphetamine and levoamphetamine, with some combinations like Adderall used for ADHD treatment.

Pharmacokinetics and Mechanism of Action

  • Pharmacokinetics:

    • Amphetamines have a longer duration of action compared to cocaine, with a half-life measured in hours,

    • Mechanism involves increased release and reuptake inhibition of dopamine, similar to cocaine but with different metabolic pathways.

Physiological Effects

  • Low doses increase cardiovascular activity and CNS stimulation, while higher doses may lead to anxiety disorders, compulsive behaviors, and deterioration of social functioning.

Tolerance and Dependence

  • Tolerance develops rapidly, requiring increasingly higher doses for effects, with a cycle of dependence characterized by compulsive use and withdrawal effects, including potential psychosis.

Non-Amphetamine Stimulants

  • Examples:

    • Synthetic cathinones (bath salts) and methamphetamine exhibit similar CNS stimulant properties with severe potential for addiction and psychosis.

Future Directions

  • Pharmacotherapy:

    • No approved medications specifically for stimulant dependencies; strategies focus on enhancing dopamine systems or blocking the effects of stimulants.

  • Experimental Approaches:

    • Drugs targeting reuptake systems and metabolism, as well as innovative vaccines aimed at preventing cocaine from reaching the brain, are under study.

This comprehensive overview captures essential details about cocaine and amphetamines, their pharmacological profiles, historical context, neurobiological impacts, and implications for treatment and prevention of stimulant dependency.