The Need to Include Pregabalin in Routine Substance Screening Panels to Detect Non Therapeutic Use and Abuse

Pregabalin, prescribed for various neurological and psychiatric conditions, has demonstrated increasing potential for abuse. Despite its psychoactive effects and growing misuse, pregabalin remains absent from standard urine drug screening panels in Türkiye. To assess the prevalence of pregabalin abuse through comprehensive biochemistry laboratory data and to underscore the necessity of including pregabalin in routine toxicological screening protocols.

This retrospective study analyzed urine drug screening results from 2019 to 2024 obtained in a tertiary hospital's biochemistry laboratory. Analysis was performed using a validated liquid chromatography system coupled with a tandem mass spectrometry method, which included pregabalin, gabapentin, and over 140 other substances. Data were stratified by year, clinical department, and co-detected substances. Urine pregabalin concentrations were statistically compared between single-use and polydrug use groups using the Mann-Whitney U-test.

Pregabalin was detected in 15%-18% of analyzed urine samples annually, sometimes exceeding methamphetamine detection rates. The majority of positive cases originated from probation services and the Alcohol and Substance Use Disorder Treatment Center outpatient clinics. Notably, urine samples with co-detected substances exhibited significantly higher pregabalin concentrations (P < .05). The most frequently co-used drugs were cannabis and methamphetamines. However, a significant subgroup used pregabalin as the sole psychoactive substance. These individuals would be misclassified as "negative" in routine screening panels that exclude pregabalin. To describe this diagnostic blind spot, the term "incomplete negativity" is proposed, referring to toxicology reports that falsely appear negative due to limited panel scope, not true drug abstinence.

Pregabalin abuse remains under-recognized due to current technical and regulatory limitations. Inclusion of pregabalin in routine drug panels is both feasible and urgently needed. The concept of incomplete negativity, introduced in this study, underscores the need to revise national toxicology practices and expand screening panels to include pregabalin. A multidisciplinary approach involving clinical psychiatry, medical biochemistry, and public health authorities is crucial. Recognizing this diagnostic gap is essential for effective clinical and legal responses to substance use disorders.