The duration of ketamine detection in hair after treatment cessation: Case study and review of the literature in forensic and clinical casework.

The disappearance of drug from hair does not occur immediately after abstinence because dormant hair may contribute to the positivity of freshly grown hair. The aim of this study was to assess ketamine disappearance from hair after treatment cessation and to review the literature data. A 22-year-old female received three intravenous doses of ketamine (171 mg) for major depression treatment. Seventeen weeks later, a 26 cm lock of hair was sampled, and ketamine was determined by liquid chromatography tandem mass spectrometry (LC-MS/MS) on seven segments: A (proximal, 0-2 cm), B (2-4 cm), C (4-6 cm, period of ketamine therapy), and D to G (4 × 5 cm). Ketamine concentration was 58 pg/mg in Segment C and remained detectable over 4 months after treatment cessation at 67 pg/mg in Segment B and 2 pg/mg in Segment A, representing a 97% drop from the initial concentration. Ketamine elimination half-life in hair was estimated at 0.88 month, implying that indetectable concentration should be expected 7 months after cessation. Axial diffusion was excluded as ketamine was not detected in Segments D-G. Given the low ketamine concentrations, norketamine was not detected. While no data on ketamine disappearance from hair have been published to date, previous studies have shown that discontinuation resulted in negative hair results after 3 months for heroin, 3-4 months for cocaine and tramadol, 6 months for amphetamine and methamphetamine, and 6-7 months for THC-COOH. This study provides useful findings for ketamine hair concentration interpretation, which should be validated by more consistent and comprehensive investigations.

Prevalence of New Psychoactive Substances (NPS) and conventional drugs of abuse (DOA) in high risk populations from Paris (France) and its suburbs: A cross sectional study by hair testing (2012-2017).

BACKGROUND: The aim of the present study is to describe the prevalence of NPS and conventional DOA in Paris and its suburbs over a six-year period using hair testing approach. METHOD: Hair was sampled in patients admitted to different departments of Paris hospitals between 2012 and 2017. Two high-risk populations were mainly considered: 1) drug-dependent and 2) acutely intoxicated patients. Segmental hair analysis was performed by validated LC-MS/MS method to screen for DOA and 83 NPS. RESULTS: 480 patients (280 M/200 F, 15-70 years) were included. 141 patients tested positive for NPS (99 M/42 F; median age: 33). NPS prevalence was 29%, that of amphetamines, cocaine and opioids were 32%, 38.5% and 52%, respectively. 27 NPS were identified, 4-MEC and mephedrone (number of cases n = 24 each) were the most detected cathinones. JWH-122 (n = 1) was the only detected synthetic cannabinoid while ketamine (n = 104) was present in numerous NPS users (67%). 3-fluorofentanyl (n = 1), furanylfentanyl (n = 1), N-ethylpentylone (n = 2), pentedrone (n = 2), mexedrone (n = 1), methcathinone (n = 3), 6-APDB (n = 2), TFMPP (n = 2), 2-CE (n = 1), 3,4-MD-αPHP (n = 1) and dextromethorphan (n = 27) were identified for the first time in hair. Users were found to have more than one NPS in 53% of cases, mostly in combination with conventional DOA. The number of detected NPS rose from 5 in 2012 to 42 in 2017. A broad range of hair concentrations (0.001-318 ng/mg) was found, but the low median concentrations seem to show an occasional exposure more than chronic use. CONCLUSION: NPS screening should be assessed in routine clinical practice, especially in high-risk populations.