Methamphetamine use in Hanoi, Vietnam, declined significantly from a peak of 359.2 to 125.6 mg/day/1000 people between 2018 and 2023, while ketamine use rose from 149.7 to 465.9 mg/day/1000 people, becoming the most commonly used illicit drug. Cocaine and heroin remained low, and MDMA was stable. After COVID-19 restrictions eased, cocaine and codeine consumption showed statistically significant declines, whereas ketamine and heroin increased slightly but not significantly. Wastewater analysis of a canal serving over 430,000 people reveals a dynamic drug market shifting toward synthetic substances, with ketamine overtaking methamphetamine as the most used drug by end of 2022.
A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously quantify four 4-substituted tryptamine drugs (psilocin, psilocybin, 4-AcO-DMT, 4-OH-DiPT) and the metabolite 4-HIAA in human plasma. Separation used a C18 column with a water-acetonitrile gradient containing 0.1% formic acid over 10 minutes. Plasma samples were stabilized with ascorbic acid, protein-precipitated with acetonitrile, dried under nitrogen, and reconstituted. The method showed high selectivity and strong linearity (R²≥0.990) across ranges such as psilocin 0.050–20 ng/mL. Detection limits reached trace levels from 0.10 to 67 pg/mL. Recovery for 4-AcO-DMT was about 70%; other substances ranged from 80% to 120% with accuracy and precision (RSD <15%) meeting US-FDA (2018) criteria. The procedure provides a sensitive, stable tool for forensic drug analysis of these tryptamines in biological samples.