Suvorexant (Belsomra®) is a novel sedative hypnotic drug that is prescribed to 
promote sleep in patients with insomnia. It is the first of a new class of drugs 
classified as dual orexin receptor antagonists (DORAs). Sedative hypnotics with 
central nervous system depressant effects feature prominently in forensic 
toxicology investigations. For this reason, a new analytical method was 
developed to identify suvorexant in urine using liquid-liquid extraction (LLE) 
and gas chromatography/mass spectrometry (GC/MS). Due to the absence of a 
commercially available isotopically labeled internal standard, estazolam-D5 was 
used due to its azepine, triazole and chlorinated functionality. The limit of 
detection and limit of quantitation was 10ng/mL and the linear range of the 
assay was 10-1000ng/mL. Accuracy and precision (%CV) were 98-101% and <11% at 
30, 250 and 800ng/mL. Interferences from matrix and fifty common drugs were not 
present and processed samples were stable for 24h at room temperature. 
Suvorexant is a new drug of significant forensic interest due to its hypnotic 
and central nervous system depressant effects. The absence of commercially 
available metabolites and its chromatographic properties present some challenges 
in terms of identification. Nevertheless, a robust, reliable and sensitive assay 
was developed to identify suvorexant using GC/MS analysis.