Disappearance of Tramadol and THC-COOH in Hair After Discontinuation of Abuse. Two Different Profiles

Tacrolimus monitoring in hair samples of kidney transplant recipients

Background

Calcineurin inhibitors, including tacrolimus, remain a cornerstone of immunosuppressive therapy after kidney transplantation. However, the therapeutic window is narrow, and nephrotoxic side effects occur with overdose, while the risk of alloimmunization and graft rejection increases with underdose. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) allows quantification of tacrolimus in biological samples from patients. This study investigates the feasibility of quantifying tacrolimus in scalp hair from kidney transplant (KT) recipients and correlates hair tacrolimus concentrations with tacrolimus dosage and blood trough levels. The aim was to provide proof-of-principle for hair tacrolimus drug monitoring in KT recipients.

Method

Single-center prospective study between September 9, 2021 and December 4, 2021, including KT recipients under tacrolimus. Minors, patients with active skin or hair diseases, and patients with scalp hair shorter than 4 cm were excluded from participation. Scalp hair was collected from the posterior vertex of patients, cut into segments, and analyzed for tacrolimus by LC-MS/MS. Patients filled out a questionnaire on hair treatments and washing habits. In parallel, tacrolimus trough levels were measured in whole blood and correlated with hair tacrolimus concentrations.

Results

In total, 39 consenting KT recipients were included, and hair samples were collected at 53 visits. Tacrolimus was detected in 98% of hair samples from patients exposed to the drug. Tacrolimus hair levels and whole blood trough levels were correlated with a beta coefficient of 0.42 (95% CI: -0.22-1.1, p = n.s.). Age and dark hair affected hair tacrolimus measurements, while different tacrolimus formulations (immediate release vs. extended release), hair washes, and permanent coloring did not. Longitudinal measurements in a subgroup of patients indicate that long-term measurement of hair tacrolimus levels is feasible.

Conclusion

Measuring tacrolimus in hair is a potentially reliable method to monitor drug exposure in KT patients. Rapid wash-in effects and consistent concentrations over time indicate that tacrolimus is incorporated into the hair matrix, allowing temporal resolution in the analysis of recent exposure and exposure history. This method provides a simple and low-risk alternative to regular blood sampling, sparing patients from frequent hospital visits through the self-collection of hair samples.

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.