Phencyclidine analog use in Sweden-intoxication cases involving 3-MeO-PCP and 4-MeO-PCP from the STRIDA project

Background. 3-Methoxy-phencyclidine (3-MeO-PCP) and 4-methoxy-phencyclidine (4-MeO-PCP) are analogs of and drug substitutes for the dissociative substance PCP (Angel dust), a recreational drug that was most popular in the 1970s. In Sweden, use of methoxylated PCP analogs was noted starting in mid-2013, according to statistics from the Poisons Information Centre. The objective of this case series was to present clinical and bioanalytical data from analytically confirmed non-fatal intoxications associated with 3-MeO-PCP and/or 4-MeO-PCP within the STRIDA project. Study design. Observational case series of consecutive patients with self-reported or suspected exposure to new psychoactive substances (NPS) and who require hospital care. Patients and methods. Blood and urine samples were collected from intoxicated patients presenting at emergency departments (ED) or intensive care units (ICU) all over Sweden. NPS analysis was performed by multicomponent liquid chromatographic-tandem mass spectrometric (LC-MS/MS) and LC-high-resolution MS (LC-HRMS) methods. Data on clinical features were collected during Poisons Information Centre consultations and retrieved from medical records. Results. The Poisons Information Centre registered its first call related to methoxylated PCP analogs in July 2013, while analytically confirmed cases first appeared in October 2013. From July 2013 to March 2015, 1243 cases of suspected NPS intoxication originating from ED or ICU were enrolled in the STRIDA project. During the 21-month period, 56 (4.5%) patients tested positive for 3-MeO-PCP and 11 (0.9%) for 4-MeO-PCP; 8 of these cases involved both substances. The 59 patients were aged 14-55 (median: 26) years and 51 (86%) were men. Co-exposure to other NPSs and/or classical drugs of abuse was common with only 7 cases (12%) indicated to be 3-MeO-PCP single-substance intoxications; prominent clinical signs seen in the latter cases were hypertension (systolic blood pressure 140 mmHg; 7 cases), tachycardia ( 100/min; 5 cases), and altered mental status (4 cases) including confusion, disorientation, dissociation, and/or hallucinations. Mixed-drug users displayed not only the same clinical features, but also more sympathomimetic effects including agitation (38%) and dilated pupils (33%). Patients testing positive for 3-/4-MeO-PCP were typically under medical care for 1-2 days (85%), and 37% of all cases were graded as severe intoxications (Poisoning Severity Score 3). Besides standard supportive therapy, 49% of the patients were treated with benzodiazepines and/or propofol. Conclusion. Laboratory analysis constitutes an important basis for the assessment of NPS hazard and availability. The adverse effects noted in cases of acute intoxications involving 3- and/or 4-MeO-PCP resembled those of other dissociatives such as PCP, ketamine, and methoxetamine. However, similar to intoxications involving other NPS, poly-substance use was found to be common.