Plant Poisons: Cocaine Overview

Plant Poisons: Cocaine

• Cocaine is a bitter, white crystalline alkaloid
• Found in the leaves of the Erythroxylon coca plant
• Cocaine content in the plant is 0.5-1%
• Used by South American natives for 1200 years
• Commonly abused drug
• Used medically as a local anesthetic (Marcaine) and antiarrhythmic (Xylocaine)
• Also used for sports doping and as an appetite suppressant (anorexigenic)

Cocaine Poisoning

• Accidental Poisoning:
  • Overdose in addicts
  • Medical overdose (anesthetic)

Routes of Administration

• Sniffing (often adulterated with less expensive substances like theophylline, quinine, or talc)
• Smoking (freebase/crack)
• Injection (often with heroin)

Mechanism of Action

• CNS stimulant:
  • Interferes with the reuptake of epinephrine and norepinephrine
  • Blocks the reuptake of dopamine
  • Interferes with serotonin activity
• Local anesthetic:
  • Blocks fast inward sodium channels

Causes of Death

• Hyperthermia
• Central asphyxia and/or circulatory collapse

Clinical Presentations (CNS Manifestations)

• Euphoria, agitation, insomnia, talkativeness
• Headache, mental confusion, hallucinations
• Exaggerated reflexes, convulsions, status epilepticus
• Hyperthermia (major cause of death)
• Increased respiratory depth and rate
• Loss of reflexes, irregular respiration, cyanosis, coma, death

Clinical Presentations (CVS Manifestations)

• Elevated blood pressure (potential for hemorrhagic stroke)
• Arrhythmias (sinus tachycardia, ventricular tachycardia/fibrillation)
• Coronary artery spasm or thrombosis (leading to myocardial infarction)
• Circulatory collapse

Clinical Presentations (Other Manifestations)

• Renal failure (from shock and decreased renal perfusion, or rhabdomyolysis/myoglobinuria)
• Perforation of nasal septum (from chronic sniffing)
• Accidental subcutaneous injection can cause localized necrotic ulcers ("coke burns")

Investigations

• Routine lab work (CBC, ABGs, kidney function tests, electrolytes)
• Serum enzymes (CPK, AST, ALT, etc.)
• Urine testing for benzoylecgonine (principle cocaine metabolite) via thin layer chromatography, high performance liquid chromatography (HPLC), or gas chromatography (GC) (detection up to 2-3 days post-use)

Treatment

• Supportive (ABCs):
  • Treat CNS stimulation with chlorpromazine
  • Treat convulsions with diazepam
  • Treat hypertension with alpha blockers (e.g., Sodium nitroprusside)
  • Treat hyperthermia with chlorpromazine and salicylates
• GIT decontamination (only if no seizures):
  • Emesis and gastric lavage
• Enhanced elimination:
  • Forced acid diuresis (increases urine excretion of the drug, but carries the risk of metabolic acidosis)
• Symptomatic:
  • Cool, quite environment
  • Lithium for cocaine psychosis
  • Propranolol for hypertension and tachycardia

Cocaine Dependence ("Cocainism")

• Street name: Crack
• Prepared from cocaine hydrochloride
• Crystalline form that makes popping/cracking sounds when heated
• Smoked, heated on water bath, or inhaled
• Euphoriant, decreases fatigue, increases sexual activity
• Rapid development of tolerance and physical dependence

Clinical Picture (Cocaine Dependence)

• Mental change: Lack of concentration, dementia
• Physical effects:
  • Anorexia, progressive weight loss
  • Pallor of the face (vasoconstriction)
  • Dilated reactive pupils, tremors, insomnia, hypertension
  • Lost sense of smell
  • Perforated nasal septum
• Moral changes: Patient becomes aggressive and dangerous
• Psychological changes: Hallucinations (chronic effects on sensory nerves), Magnan's symptoms (feeling of sand or insects under skin, severe itching)
• Withdrawal symptoms: Irritability, neurological pain in arms/legs, tendency to violence (less severe than opiate withdrawal)

Treatment (Cocaine Dependence)

• Abrupt withdrawal in an institute
• Psychological care, tranquilizers
• Symptomatic treatment
• Hypertension and arrhythmias treated with beta blockers

Explore the intricacies of cocaine, a potent plant-derived alkaloid. This quiz covers its historical use, methods of administration, mechanisms of action, and the risks associated with its abuse and poisoning. Delve into the dual nature of cocaine as both a medical anesthetic and a potentially lethal drug.