Methamphetamine as the most common concomitant substance used with pregabalin misuse.

Background And Aim: Non-medical use of Pregabalin (PGB) is a growing concern in many countries because of the serious consequences associated with their abuse. Judicial cases within the probation system, multiple drug users, and patients in treatment programs administered PGB at higher doses than suggested, commonly without prescription. For this reason, it is important to analyze PGB by adding it to the routine analysis scale in determining whether PGB is used for medical purposes or abuse. In this study, PGB analyzed (single or multiple substance use, concomitant substances) in urine samples of forensic and clinical cases by liquid chromatography-tandem mass spectrometry (LC-MS/MS). In addition to the sociodemographic and clinical characteristics of pregabalin-positive cases, the results were evaluated separately from a clinical and forensic perspective.

Methods: All urine samples which was admitted to Addiction Toxicology Laboratory from 'drug abuse probation system' (forensic cases, n = 640) and from various departments of our hospital (clinical cases, n = 371) between December 2022 and April 2023. Screening analysis were carried out by immunoassay in total 1011 cases. LC-MS/MS method simultaneously analyzed amphetamine, benzoilecgonine, cocaine, codeine, metamphetamine, morphine, 3,4-metilenedioksi-N-metilamfetamin (MDMA), 11-nor-9-karboksi-Δ9-tetrahidrokannabinol and pregabalin in urine samples. PGB was added to the our routine substance screening analysis scale in December 2022 to detect pregabalin use.

Results: PGB was detected in 12.3% of probabition cases and 13.2% of clinical cases. The mean age of PGB positive cases was 26.55 ± 7,52 years old, predominantly males (%85,9). Single PGB was detected in 53.2% of forensic cases (n = 42), and 38.7% of clinical cases (n = 19). The most common substance detected concomitantly with PGB was amphetamine type stimulants (ATSs:amphetamine, methamphetamine, ecstasy/MDMA etc.) (22.8% of forensic cases and 46.9% of clinical cases), followed by concomitant cannabis use (24.1% of forensic cases and 26.5% of clinical cases). Concomitant opioid use was rare (1.3% of forensic cases and 4.1% of clinical cases). Detection of PGB was significantly different across months on which the samples were collected (x = 82.8, df=4, p < 0.001).

Conclusion: Inconsistently with previous studies suggesting opioids as the most prevalant substances concominant with PGB, our results showed that stimulants (especially ATSs) were the most prevelant substances concominant with PGB, followed by cannabis. High proportion of PGB detection in probabition cases, frequently as a single substance abuse takes attention. These results suggest that PGB, may be used to avoid legal consequences. It is important for laboratories to be aware that they need to make changes as addition of newly abused substances in their analysis panels, when necessary, as differences between regions and cultures affect substance use patterns.