Since November 2018, the ketamine analog fluorodeschloroketamine (FDCK) has appeared in Hong Kong forensic cases. A retrospective study of drug seizures and driving-under-the-influence cases up to December 2019 found 74 drug seizure cases (151 items) and 6 drug driving cases. Most seized items contained only FDCK (about 67%) or a mixture with ketamine (about 28%), with purity similar to ketamine seizures. In drug driving cases, blood FDCK concentrations ranged from below 0.002 to 1.1 μg/mL, and other psychoactive substances were also present. The two cases with highest FDCK blood levels (1.1 and 0.87 μg/mL) may have contributed to impairment, though other drugs complicate interpretation.
A roadside testing protocol using field impairment tests (FIT) can detect ketamine-impaired drivers with over 90% accuracy when salivary ketamine concentrations exceed 300 ng/mL. Among 62 volunteers exiting discos in Hong Kong, 39 had ketamine in their oral fluid. Of 21 ketamine-only users, 71% were identified by FIT. Typical signs of ketamine impairment include lack of convergence, horizontal gaze nystagmus, elevated pulse rate, and poor performance on divided attention tests, particularly walk-and-turn and one-leg stand.