Metabolism, Not Mendacity: Rethinking Prolonged Cocaine Positivity

Area of Science:

• Pharmacogenomics
• Addiction Medicine
• Clinical Toxicology

Background:

• Urine toxicology is vital for monitoring substance use disorder treatment.
• Standard detection windows may not reflect individual metabolic variability.
• Misinterpreting prolonged positivity as relapse can harm patient treatment.

Purpose of the Study:

• To highlight how metabolic variability can cause prolonged cocaine metabolite detection.
• To emphasize the importance of considering pharmacokinetic factors in toxicology.
• To advocate for patient-centered interpretation of urine drug screens.

Main Methods:

• Case report of a patient with stimulant use disorder and prolonged cocaine metabolite positivity.
• Laboratory evaluation including hepatic steatosis assessment.
• Pharmacogenomic testing revealing CYP2D6 and CYP3A5 poor metabolizer phenotypes.

Main Results:

• Cocaine metabolites remained positive for 18 days, 12 days after verified abstinence.
• Patient exhibited poor metabolizer phenotypes for CYP2D6 and CYP3A5.
• Monotonic decline in metabolite levels suggested delayed elimination, not recurrent use.

Conclusions:

• Impaired CYP450 enzyme activity, hepatic steatosis, and stimulant use can prolong cocaine metabolite clearance.
• Distinguishing biological variability from relapse is essential for therapeutic rapport.
• Consider pharmacogenomic variation and liver function in cases of unexpected persistent positivity.