Cocaine


  • Cocaine is an ester-linked local anaesthetic derived from Erythroxylon coca
  • It is used for topical anaesthesia and local vasoconstriction, but also as a drug of abuse
Cocaine chemical structure
  • Paste (1-4%)
  • As a part of Moffatt's solution:
    • 2ml 8% cocaine
    • 2ml 1% sodium bicarbonate
    • 1ml 1:1,000 adrenaline

  • Blocks Uptake 1 and MAO
  • This stimulates the sympathetic nervous system, leading to hypertension, tachycardia and hyperthermia
  • Side-effects include:
    • Tachyarrhythmia
    • Coronary artery vasospasm, increasing risk of myocardial infarction
    • Confusion
    • Seizures
    • Hallucinations

Absorption

  • pKa 8.6
  • 5% unionised at physiological pH
  • Well absorbed from mucous membranes

Distribution

  • 95% protein bound
  • Is the archetypal LA off which all other LA potencies and lipid solubilites are based

Metabolism

  • Exclusively hepatic by hydrolysis to inactive metabolites that are excreted in the urine

Excretion

  • Elimination half-life 80mins