Disappearance of Tramadol and THC-COOH in Hair After Discontinuation of Abuse. Two Different Profiles.
Level 4 - case-series / case-control
Small observational case series evaluating segmental hair drug clearance profiles without a control group.
PubMed 30715334 · doi:10.1093/jat/bkz004
What was done
Segmental hair analysis using liquid chromatography-tandem mass spectrometry (LC-MS-MS) was performed on hair from 8 chronic tramadol abusers (collected 3–6 months post-cessation; limit of quantitation 5 pg/mg) and 15 chronic cannabis abusers (collected 6–9 months post-cessation; limit of quantitation 0.2 pg/mg for THC-COOH). Hair was cut into 1-cm segments (assuming a growth rate of 1 cm/month) relative to self-reported dates of cessation to assess the lag time until hair segments tested negative.
What was found
Baseline concentrations in the segment immediately preceding cessation ranged from 895 to 21,010 pg/mg for tramadol and 2.3 to 8.9 pg/mg for THC-COOH. Both drugs persisted across a transition zone in subsequent growing hair segments. Negative hair results were achieved ~3–4 months after tramadol cessation and ~6–7 months after cannabis cessation.
Why it matters
Because of telogen (dormant) hair and incorporation dynamics, newly grown hair does not immediately become drug-free after quitting. Interpreting segmental hair testing to confirm abstinence requires accounting for clearance delays of several months depending on the drug.
Limits
Small sample size (n = 8 for tramadol, n = 15 for cannabis). Drug discontinuation dates relied entirely on subject self-report. A uniform 1 cm/month growth rate was assumed rather than individually measured.