How long do cocaine and its metabolites, particularly benzoylecgonine, remain detectable in urine after a single use?

Detection Window for Cocaine Metabolites After Single Use

After a single use of cocaine, benzoylecgonine (the primary metabolite) remains detectable in urine for approximately 24-48 hours in most individuals, with the mean time to first negative urine specimen being 43.6 ± 17.1 hours. 1, 2

Standard Detection Timeline

The detection window follows a predictable pattern after single use:

• Peak detection occurs in the first urine specimen collected, with cocaine itself rapidly metabolized and typically undetectable within 24 hours 3
• Benzoylecgonine concentrations decrease to approximately 33% at 24 hours, 8% at 48 hours, and 4% at 72 hours compared to initial levels 4
• The urinary half-life of benzoylecgonine is 6-8 hours 1
• Standard cutoff for positive testing is benzoylecgonine >300 ng/mL using qualitative immunoassay, which is the most commonly used laboratory method 1

Route of Administration Considerations

The route of administration affects metabolite excretion patterns:

• Intravenous administration produces the highest urinary benzoylecgonine recovery (approximately 39% of administered dose) 3
• Intranasal administration yields approximately 30% recovery 3
• Smoked cocaine produces the lowest recovery at approximately 16% 3

Important Clinical Caveats

Significant fluctuation in metabolite concentrations occurs across successive urine specimens, which creates potential testing pitfalls:

• 69% of chronic users tested positive at least once after initially testing negative, demonstrating the unreliability of single negative tests 4
• The mean time to last positive specimen was 57.5 ± 31.6 hours (range 11-147 hours) after admission in chronic users, though this extends detection beyond what occurs with single use 4
• Creatinine normalization (cutoff 300 ng/mg creatinine) increases detection time but does not reduce fluctuation between specimens 4

Testing Methodology

Qualitative immunoassay screening followed by confirmatory testing is the standard approach:

• Screening sensitivity is 96% at 4-6 hours and 90% at 24 hours after use 5
• Quantitative methods are more expensive and potentially misleading due to individual variability in cocaine metabolism and excretion 1
• Gas chromatography-mass spectrometry provides highly specific confirmation when needed 5

Factors Affecting Detection

Individual variability influences detection windows:

• Body mass index negatively correlates with urine benzoylecgonine concentration (higher BMI = lower concentrations) 5
• Urine creatinine concentration positively correlates with benzoylecgonine levels 5
• Urine pH and concentration affect detection times 6

For single-use scenarios, expect reliable detection for 24-48 hours, with most individuals testing negative by 48-72 hours. 1, 2, 4