What is the half-life of cocaine?

Cocaine Half-Life

The half-life of cocaine in the body is approximately 1-1.5 hours in plasma, but its metabolite benzoylecgonine has a much longer urinary half-life of 6-8 hours, allowing detection in urine for 24-48 hours after use. 1

Pharmacokinetic Profile of Cocaine

Cocaine's pharmacokinetics vary based on several factors:

Plasma Half-Life

• Intravenous administration: 1-1.5 hours 1, 2
• Intranasal administration: 0.7-1.25 hours 3, 4
• Dose-dependent effects: Higher doses can extend the half-life, with the terminal plasma half-life increasing by approximately 24.5 minutes per mg/kg dose 2

Metabolite Detection

• Benzoylecgonine (primary metabolite):
  • Urinary half-life: 6-8 hours 1
  • Detection window: 24-48 hours in typical users 1
  • In chronic, heavy users (up to 10g/day): Can be detected up to 22 days after last use 1

Route of Administration Effects

• Intranasal absorption half-life: Approximately 8 minutes 2
• Bioavailability:
  • Intranasal: Approximately 60% 2
  • Higher doses may have better relative bioavailability 4

Factors Affecting Cocaine Elimination

Several factors can significantly alter cocaine's half-life and detection window:

• Chronic use: Creates a biphasic elimination pattern with an initial phase similar to acute use, followed by a prolonged terminal elimination phase (mean 19 hours) due to drug accumulation 5

• Co-ingestion with alcohol: Forms cocaethylene, which has:

  • Longer half-life (~2 hours vs ~1 hour for cocaine) 6
  • Greater toxicity to heart and liver 6
  • Similar dopaminergic effects to cocaine 6

• Individual metabolic variations: Significant person-to-person variability in cocaine metabolism and excretion 1

Clinical Implications

The relatively short half-life of cocaine explains several important clinical phenomena:

• Rapid onset and short duration of euphoria: Consistent with the drug's short plasma half-life
• Binge patterns of use: Users often take repeated doses to maintain effects
• Detection challenges: The short half-life of the parent compound makes detection difficult after 24 hours in casual users
• Extended detection in chronic users: Due to accumulation and the longer terminal elimination phase 5

Detection Methods

• Urine testing: Most common method, detects benzoylecgonine above 300 ng/mL 1
• Blood testing: Limited window due to cocaine's short half-life
• Hair testing: Can detect use over longer periods 1

For clinical evaluation, self-reporting remains the primary method for establishing cocaine use, with urine testing recommended only in specific cases such as when patients cannot communicate or have unclear history 1.