RT Journal Article T1 Disappearance of codeine, morphine and 6-MAM in hair after cessation of abuse A1 Suárez-García, A. A1 Álvarez Freire, Iván A1 Bermejo Barrera, Ana María A1 Cabarcos Fernández, Pamela A1 Tabernero Duque, María Jesús K1 Abstinence time K1 Opioids K1 Cessation drug use K1 Hair analysis AB Research on the determination of drugs of abuse in hair has established that drugs can be detected in hair even long after cessation of use. The purpose of this study was to analyze hair samples from chronic opioid users who were beginning a controlled drug cessation program. The study population (n = 15) is involved in a drug rehabilitation program in Santiago de Compostela, Spain. Over a 6-month period, subjects provided hair samples at 2-month intervals, with the first sample collected on the day they began the program. Codeine, morphine, and 6-MAM were analyzed by GC/MS (LOQ = 0.2 ng/mg). Hair tresses were divided into 1 cm segments and analyzed for all analytes 0–1 cm corresponding to the proximal portion to the scalp Following cessation of opioid use, traces of codeine, morphine, and 6-MAM still remained in the newly growing hair segments for a specified period. After 2 months, still 27 % of the users tested positive, and at 4 months, 20 % were positive but only for 6-MAM. However, after 6 months of abstinence, the results were negative for all analytes. PB Elsevier SN 0379-0738 YR 2023 FD 2023 LK http://hdl.handle.net/10347/33004 UL http://hdl.handle.net/10347/33004 LA eng NO Forensic Science International Volume 352, November 2023, 111855 DS Minerva RD 24 abr 2026