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

Abstract

The retrospective calendar of an individual s drug use requires a multisectional analysis in which the length of hair, corresponding to the full temporal window available, is cut into shorter sections to measure drug use during shorter periods of time (generally 1 cm corresponds to ~1 month). Segmental hair analysis is used to verify both previous drug history and recent enforced abstinence. However, after drug discontinuation, the fresh new hair growth segment cannot be immediately negative, due to the contribution of dormant hair. The objective of the study was to test hair samples from chronic tramadol and cannabis users after the discontinuation of both drugs and to evaluate the delay to wait until the hair will become negative. Hair specimens were obtained from eight subjects with a known history of tramadol abuse. Hair was collected 3-6 months after tramadol discontinuation. Tramadol was tested by liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS) with a LOQ at 5 pg/mg. A second set of hair specimens were obtained from 15 subjects with a known history of cannabis abuse. Hair was collected 6-9 months after cannabis discontinuation. THC-COOH was tested by LC-MS-MS with a LOQ at 0.2 pg/mg. The hair stands were cut into L × 1 cm segments, according to their length (L), and tested for the respective drug. It was asked to each subject to clearly indicate the date of drug discontinuation. Assuming a rate of hair growth of 1 cm/month, the segment corresponding to the time of last drug use was calculated. The older segment just before this one was considered as the 100% of the response. THC-COOH and tramadol concentrations in this segment ranged from 2.3 to 8.9 and 895 to 21,010 pg/mg, respectively. After cessation of drug consumption, the presence of both drugs in new growing hair segments continued for a certain period with a more or less broad transition zone. Negative hair results were obtained ~3-4 and 6-7 months after cessation of tramadol and cannabis abuse.