10.Cerebral stimulants

Cocaine

• Source: Extracted from the leaves of Erythroxylum coca

  • Grown in South America (e.g., Colombia, Bolivia, Java)

• Chemical Composition: Cocaine hydrochloride

  • Colorless, odorless, crystalline substance with a bitter taste

Uses

• Local Anesthetic:

  • Applied to glans penis and vaginal mucosa

  • Produces local anesthesia to prolong sexual activity and enhance pleasure

Street Names of Cocaine

• Coke

• Crack

• Snow

• Cadillac

• White Lady

• Charlie

• Big-C

• Pasta

• Bazooko

• Paco

Active Principle

• Cocaine Hydrochloride (Benzoyl methyl ecgonine)

  • An alkaloid deliriant concentrated in coca leaves

Mechanism of Action

• Increases concentrations of neurotransmitters:

  • Dopamine

  • Nor-epinephrine

  • Serotonin

• Action Mechanism:

  • Binds to monoamine transporters in pre-synaptic neurons

  • Blocks reuptake of neurotransmitters in synapses

  • Initially stimulates cerebral cortex, then depresses it

  • Similar action on spinal cord, but less marked

Locally Anesthetic Properties

• Desensitizes terminal nerves

• Causes vasoconstriction at the application site

Absorption and Routes of Administration

• Rapid absorption from mucous membranes

• Common Routes:

  • Nasal mucosa (snorting)

  • Intravenous (IV)

  • Smoking (crack cocaine: cocaine mixed with baking soda)

• Speedball: Combination of cocaine and heroin taken by injection

Effects of Overdose

• Large doses may induce panic or paranoia

Metabolism and Excretion

• 30-50% hydrolyzed to ecgonine methyl ester by plasma and hepatic esterases

• Remaining undergoes spontaneous non-enzymatic hydrolysis to form benzoyl ecgonine

• Unaltered cocaine (15%) and metabolites are excreted in urine within 24 hours.

Signs and Symptoms of Cocaine Use

Onset of Symptoms

• Rapid onset when cocaine is snorted, injected (i.v.), or smoked

• Symptoms appear within half an hour when ingested

I. Stage of Excitement

• Local effects: Numbness or tingling at the application site

• Facial effects: Flushed skin, muscle twitching

• Gastrointestinal effects: Bitter taste, dryness, difficulty swallowing (dysphagia), vomiting, diarrhea, increased bowel sounds

• Central Nervous System (CNS): Euphoria, well-being, loss of fatigue; symptoms include:

  • Excitement, restlessness, talkativeness

  • Delirium, maniacal hallucinations, tremors, tonic-clonic seizures

  • Exaggerated reflexes

• Cardiovascular System (CVS): Increased heart rate, hypertension, ventricular arrhythmias

• Respiratory System (RS): Tachypnea, dyspnea, cyanosis

• Temperature: Hyperthermia

• Ocular: Dilated pupils, blurring of vision

II. Stage of Depression

• Gradual reduction in feelings of well-being, followed by periods of depression usually after 1 hour

• CNS effects: Headache, hypotension, excessive sweating (profuse perspiration), apathy, depression, tremors, pupil dilation, potential convulsions, suicidal tendencies

• Overdose risks: Coma, ventricular dysrhythmias, irregular pulse, circulatory failure, cardiac arrest

• Respiratory concerns: Cheyne-Stokes respiration, apnea, cyanosis, pulmonary edema, respiratory failure

• Fatal risks: Death may result from respiratory failure, cardiac failure, vascular collapse;

• Sudden death may occur following i.v. injection, snorting, or smoking due to cardiac arrhythmias from coronary spasms

Fatal Dosage

• Oral: 500 mg

• I.V.: 20 mg

• Fatal period: Few minutes to few hours

Treatment for Cocaine Overdose

1. Stomach wash and activated charcoal if ingested

2. Control convulsions with barbiturates or diazepam

3. Maintain airway

4. Administer amyl nitrite by inhalation as antidote

5. Administer thiamine 100 mg i.v.

6. Provide symptomatic management

Postmortem Appearances

• Internal organs will be congested

• Congested and edematous lungs, brain

• Preserve blood for chemical analysis

Chronic Cocaine Use

• Known as Cocainism/Cocainomania

• Tolerance develops; chronic users may tolerate up to 10 g per day

• Physical effects: Pale face, sunken eyes, emaciation, tooth discoloration, and bruxism (involuntary tooth grinding)

• Withdrawal from social activities: Loss of interest in friends, family, food, sexual activity

• Health risks include persistent rhinitis, nasal erosion with perforation, bronchitis due to chronic sniffing

• Male-specific effects: Loss of libido, impotence, infertility

• Female-specific effects: Galactorrhea, amenorrhea, infertility

• Psychological Symptoms:

  • Paranoid or depressive psychosis

  • Hallucinations, delusions, convulsions, and delirium

  • Magnan's symptom (UQ): Tactile hallucinations where users feel insects crawling under the skin (also called "Cocaine bugs" or "Formication").

• Physiological Symptoms:

  • Crack lung:

    • Hyper-sensitivity resulting in bronchospasm, dyspnea, and pneumonia due to cocaine smoking.

  • Crack dancing (Charley dance):

    • Characterized by extra-pyramidal signs and symptoms after cocaine intake.

Medicolegal Considerations

• Use in Crime:

  • Rarely used for suicidal or homicidal purposes.

  • Popular drug of abuse, second to cannabis.

  • Street names include crack, pasta, bazooko, speedball, etc.

• Risks of Use:

  • Accidental death may occur from cardiac arrest during cocaine injections due to coronary spasm.

  • Believed to have aphrodisiac effects, used to prolong sexual intercourse by numbing the nerves in glans penis and vaginal mucosa.